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gerrit-public.fairphone.software / toolchain / llvm-project / 80d73c7ee796d6570405e1fc871b2cde1f7c16a4 / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
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>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]52 </ol>
53 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]58 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 </ol>
65 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]68 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]73 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]74 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]78 </ol>
79 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]80 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]81 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]88 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]89 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]116 </ol>
117 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]132 </ol>
133 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]142 </ol>
143 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]149 </ol>
150 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]158 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]159 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
160 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]165 </ol>
166 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]167 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]181 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]191 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]192 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]193 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]194 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]195 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]196 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]202 </ol>
203 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]209 </ol>
210 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]220 </ol>
221 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]232 </ol>
233 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]235 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <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]249 <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]250 </ol>
251 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]276 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]277 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]278 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]279 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]280 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]281 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]282 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]283 '<tt>llvm.trap</tt>' Intrinsic</a></li>
284 <li><a href="#int_stackprotector">
285 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]286 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]287 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]288 </ol>
289 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]290</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]291
292<div class="doc_author">
293 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
294 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]295</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]296
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]297<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]298<div class="doc_section"> <a name="abstract">Abstract </a></div>
299<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]300
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]301<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]302
303<p>This document is a reference manual for the LLVM assembly language. LLVM is
304 a Static Single Assignment (SSA) based representation that provides type
305 safety, low-level operations, flexibility, and the capability of representing
306 'all' high-level languages cleanly. It is the common code representation
307 used throughout all phases of the LLVM compilation strategy.</p>
308
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]309</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]310
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]311<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]312<div class="doc_section"> <a name="introduction">Introduction</a> </div>
313<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]314
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]315<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]316
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]317<p>The LLVM code representation is designed to be used in three different forms:
318 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
319 for fast loading by a Just-In-Time compiler), and as a human readable
320 assembly language representation. This allows LLVM to provide a powerful
321 intermediate representation for efficient compiler transformations and
322 analysis, while providing a natural means to debug and visualize the
323 transformations. The three different forms of LLVM are all equivalent. This
324 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]325
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]326<p>The LLVM representation aims to be light-weight and low-level while being
327 expressive, typed, and extensible at the same time. It aims to be a
328 "universal IR" of sorts, by being at a low enough level that high-level ideas
329 may be cleanly mapped to it (similar to how microprocessors are "universal
330 IR's", allowing many source languages to be mapped to them). By providing
331 type information, LLVM can be used as the target of optimizations: for
332 example, through pointer analysis, it can be proven that a C automatic
333 variable is never accessed outside of the current function... allowing it to
334 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]335
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]336</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]337
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]338<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]339<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]341<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]343<p>It is important to note that this document describes 'well formed' LLVM
344 assembly language. There is a difference between what the parser accepts and
345 what is considered 'well formed'. For example, the following instruction is
346 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]347
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]348<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]349<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]350%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]351</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]352</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]354<p>...because the definition of <tt>%x</tt> does not dominate all of its
355 uses. The LLVM infrastructure provides a verification pass that may be used
356 to verify that an LLVM module is well formed. This pass is automatically run
357 by the parser after parsing input assembly and by the optimizer before it
358 outputs bitcode. The violations pointed out by the verifier pass indicate
359 bugs in transformation passes or input to the parser.</p>
360
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]361</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]362
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]363<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]364
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]365<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]366<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]367<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]368
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]369<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]371<p>LLVM identifiers come in two basic types: global and local. Global
372 identifiers (functions, global variables) begin with the <tt>'@'</tt>
373 character. Local identifiers (register names, types) begin with
374 the <tt>'%'</tt> character. Additionally, there are three different formats
375 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]376
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]377<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]378 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]379 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
380 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
381 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
382 other characters in their names can be surrounded with quotes. Special
383 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
384 ASCII code for the character in hexadecimal. In this way, any character
385 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]387 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]388 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]389
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]390 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]391 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]392</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]393
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]394<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]395 don't need to worry about name clashes with reserved words, and the set of
396 reserved words may be expanded in the future without penalty. Additionally,
397 unnamed identifiers allow a compiler to quickly come up with a temporary
398 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]399
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]400<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]401 languages. There are keywords for different opcodes
402 ('<tt><a href="#i_add">add</a></tt>',
403 '<tt><a href="#i_bitcast">bitcast</a></tt>',
404 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
405 ('<tt><a href="#t_void">void</a></tt>',
406 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
407 reserved words cannot conflict with variable names, because none of them
408 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]409
410<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]411 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]412
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]413<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]415<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]416<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]417%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]418</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]419</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]420
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]421<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]423<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]424<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]425%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]426</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]427</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]428
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]429<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]431<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]433<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
434<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
435%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]437</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]438
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]439<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
440 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]442<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]443 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]444 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]445
446 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]447 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]449 <li>Unnamed temporaries are numbered sequentially</li>
450</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]452<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]453 demonstrating instructions, we will follow an instruction with a comment that
454 defines the type and name of value produced. Comments are shown in italic
455 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]457</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]458
459<!-- *********************************************************************** -->
460<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
461<!-- *********************************************************************** -->
462
463<!-- ======================================================================= -->
464<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
465</div>
466
467<div class="doc_text">
468
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]469<p>LLVM programs are composed of "Module"s, each of which is a translation unit
470 of the input programs. Each module consists of functions, global variables,
471 and symbol table entries. Modules may be combined together with the LLVM
472 linker, which merges function (and global variable) definitions, resolves
473 forward declarations, and merges symbol table entries. Here is an example of
474 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]475
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]476<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]477<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]478<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
479 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]480
481<i>; External declaration of the puts function</i>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]482<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]483
484<i>; Definition of main function</i>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]485define i32 @main() { <i>; i32()* </i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]486 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]487 %cast210 = <a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]488 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]489
490 <i>; Call puts function to write out the string to stdout...</i>
491 <a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]492 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]494 href="#i_ret">ret</a> i32 0<br>}<br>
495</pre>
496</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]498<p>This example is made up of a <a href="#globalvars">global variable</a> named
499 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
500 a <a href="#functionstructure">function definition</a> for
501 "<tt>main</tt>".</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]502
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]503<p>In general, a module is made up of a list of global values, where both
504 functions and global variables are global values. Global values are
505 represented by a pointer to a memory location (in this case, a pointer to an
506 array of char, and a pointer to a function), and have one of the
507 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]508
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
513 <a name="linkage">Linkage Types</a>
514</div>
515
516<div class="doc_text">
517
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]518<p>All Global Variables and Functions have one of the following types of
519 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]520
521<dl>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]522 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]523 <dd>Global values with private linkage are only directly accessible by objects
524 in the current module. In particular, linking code into a module with an
525 private global value may cause the private to be renamed as necessary to
526 avoid collisions. Because the symbol is private to the module, all
527 references can be updated. This doesn't show up in any symbol table in the
528 object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]529
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]531 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattnere7f064e2009-08-24 04:32:16 +0000[diff] [blame]532 removed by the linker after evaluation. Note that (unlike private
533 symbols) linker_private symbols are subject to coalescing by the linker:
534 weak symbols get merged and redefinitions are rejected. However, unlike
535 normal strong symbols, they are removed by the linker from the final
536 linked image (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]537
Dale Johannesen4188aad2008-05-23 23:13:41 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]539 <dd>Similar to private, but the value shows as a local symbol
540 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
541 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]542
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]544 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]545 into the object file corresponding to the LLVM module. They exist to
546 allow inlining and other optimizations to take place given knowledge of
547 the definition of the global, which is known to be somewhere outside the
548 module. Globals with <tt>available_externally</tt> linkage are allowed to
549 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
550 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]551
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]552 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]553 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]554 the same name when linkage occurs. This is typically used to implement
555 inline functions, templates, or other code which must be generated in each
556 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
557 allowed to be discarded.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]558
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]560 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
561 <tt>linkonce</tt> linkage, except that unreferenced globals with
562 <tt>weak</tt> linkage may not be discarded. This is used for globals that
563 are declared "weak" in C source code.</dd>
564
565 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
566 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
567 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
568 global scope.
569 Symbols with "<tt>common</tt>" linkage are merged in the same way as
570 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]571 <tt>common</tt> symbols may not have an explicit section,
572 must have a zero initializer, and may not be marked '<a
573 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
574 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]575
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]576
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]578 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]579 pointer to array type. When two global variables with appending linkage
580 are linked together, the two global arrays are appended together. This is
581 the LLVM, typesafe, equivalent of having the system linker append together
582 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]583
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]585 <dd>The semantics of this linkage follow the ELF object file model: the symbol
586 is weak until linked, if not linked, the symbol becomes null instead of
587 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]588
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame^]589 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
590 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]591 <dd>Some languages allow differing globals to be merged, such as two functions
592 with different semantics. Other languages, such as <tt>C++</tt>, ensure
593 that only equivalent globals are ever merged (the "one definition rule" -
594 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
595 and <tt>weak_odr</tt> linkage types to indicate that the global will only
596 be merged with equivalent globals. These linkage types are otherwise the
597 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]598
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]600 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]601 visible, meaning that it participates in linkage and can be used to
602 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]603</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]604
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]605<p>The next two types of linkage are targeted for Microsoft Windows platform
606 only. They are designed to support importing (exporting) symbols from (to)
607 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]608
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]609<dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]611 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]612 or variable via a global pointer to a pointer that is set up by the DLL
613 exporting the symbol. On Microsoft Windows targets, the pointer name is
614 formed by combining <code>__imp_</code> and the function or variable
615 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]616
617 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]618 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]619 pointer to a pointer in a DLL, so that it can be referenced with the
620 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
621 name is formed by combining <code>__imp_</code> and the function or
622 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]623</dl>
624
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]625<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
626 another module defined a "<tt>.LC0</tt>" variable and was linked with this
627 one, one of the two would be renamed, preventing a collision. Since
628 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
629 declarations), they are accessible outside of the current module.</p>
630
631<p>It is illegal for a function <i>declaration</i> to have any linkage type
632 other than "externally visible", <tt>dllimport</tt>
633 or <tt>extern_weak</tt>.</p>
634
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]635<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]636 or <tt>weak_odr</tt> linkages.</p>
637
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]642 <a name="callingconv">Calling Conventions</a>
643</div>
644
645<div class="doc_text">
646
647<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]648 and <a href="#i_invoke">invokes</a> can all have an optional calling
649 convention specified for the call. The calling convention of any pair of
650 dynamic caller/callee must match, or the behavior of the program is
651 undefined. The following calling conventions are supported by LLVM, and more
652 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]653
654<dl>
655 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]656 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]657 specified) matches the target C calling conventions. This calling
658 convention supports varargs function calls and tolerates some mismatch in
659 the declared prototype and implemented declaration of the function (as
660 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]661
662 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]663 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]664 (e.g. by passing things in registers). This calling convention allows the
665 target to use whatever tricks it wants to produce fast code for the
666 target, without having to conform to an externally specified ABI
667 (Application Binary Interface). Implementations of this convention should
668 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
669 optimization</a> to be supported. This calling convention does not
670 support varargs and requires the prototype of all callees to exactly match
671 the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]672
673 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]674 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]675 as possible under the assumption that the call is not commonly executed.
676 As such, these calls often preserve all registers so that the call does
677 not break any live ranges in the caller side. This calling convention
678 does not support varargs and requires the prototype of all callees to
679 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]680
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]681 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]682 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]683 target-specific calling conventions to be used. Target specific calling
684 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]685</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686
687<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]688 support Pascal conventions or any other well-known target-independent
689 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]690
691</div>
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]695 <a name="visibility">Visibility Styles</a>
696</div>
697
698<div class="doc_text">
699
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]700<p>All Global Variables and Functions have one of the following visibility
701 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]702
703<dl>
704 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]705 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]706 that the declaration is visible to other modules and, in shared libraries,
707 means that the declared entity may be overridden. On Darwin, default
708 visibility means that the declaration is visible to other modules. Default
709 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]710
711 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]712 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol
715 table, so no other module (executable or shared library) can reference it
716 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]717
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]718 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]719 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]720 the dynamic symbol table, but that references within the defining module
721 will bind to the local symbol. That is, the symbol cannot be overridden by
722 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<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]735 it easier to read the IR and make the IR more condensed (particularly when
736 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]744<p>You may give a name to any <a href="#typesystem">type</a> except
745 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
746 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]747
748<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]749 and that you can therefore specify multiple names for the same type. This
750 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
751 uses structural typing, the name is not part of the type. When printing out
752 LLVM IR, the printer will pick <em>one name</em> to render all types of a
753 particular shape. This means that if you have code where two different
754 source types end up having the same LLVM type, that the dumper will sometimes
755 print the "wrong" or unexpected type. This is an important design point and
756 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]757
758</div>
759
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]767<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]768 instead of run-time. Global variables may optionally be initialized, may
769 have an explicit section to be placed in, and may have an optional explicit
770 alignment specified. A variable may be defined as "thread_local", which
771 means that it will not be shared by threads (each thread will have a
772 separated copy of the variable). A variable may be defined as a global
773 "constant," which indicates that the contents of the variable
774 will <b>never</b> be modified (enabling better optimization, allowing the
775 global data to be placed in the read-only section of an executable, etc).
776 Note that variables that need runtime initialization cannot be marked
777 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]778
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]779<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
780 constant, even if the final definition of the global is not. This capability
781 can be used to enable slightly better optimization of the program, but
782 requires the language definition to guarantee that optimizations based on the
783 'constantness' are valid for the translation units that do not include the
784 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]785
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]786<p>As SSA values, global variables define pointer values that are in scope
787 (i.e. they dominate) all basic blocks in the program. Global variables
788 always define a pointer to their "content" type because they describe a
789 region of memory, and all memory objects in LLVM are accessed through
790 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]791
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]792<p>A global variable may be declared to reside in a target-specific numbered
793 address space. For targets that support them, address spaces may affect how
794 optimizations are performed and/or what target instructions are used to
795 access the variable. The default address space is zero. The address space
796 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]797
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]798<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]799 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]800
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]801<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]802 the alignment is set to zero, the alignment of the global is set by the
803 target to whatever it feels convenient. If an explicit alignment is
804 specified, the global is forced to have at least that much alignment. All
805 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]806
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]807<p>For example, the following defines a global in a numbered address space with
808 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]809
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]810<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]811<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]812@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]813</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]814</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]815
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]816</div>
817
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="functionstructure">Functions</a>
822</div>
823
824<div class="doc_text">
825
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
827 optional <a href="#linkage">linkage type</a>, an optional
828 <a href="#visibility">visibility style</a>, an optional
829 <a href="#callingconv">calling convention</a>, a return type, an optional
830 <a href="#paramattrs">parameter attribute</a> for the return type, a function
831 name, a (possibly empty) argument list (each with optional
832 <a href="#paramattrs">parameter attributes</a>), optional
833 <a href="#fnattrs">function attributes</a>, an optional section, an optional
834 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
835 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]836
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
838 optional <a href="#linkage">linkage type</a>, an optional
839 <a href="#visibility">visibility style</a>, an optional
840 <a href="#callingconv">calling convention</a>, a return type, an optional
841 <a href="#paramattrs">parameter attribute</a> for the return type, a function
842 name, a possibly empty list of arguments, an optional alignment, and an
843 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]844
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]845<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]846 (Control Flow Graph) for the function. Each basic block may optionally start
847 with a label (giving the basic block a symbol table entry), contains a list
848 of instructions, and ends with a <a href="#terminators">terminator</a>
849 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]850
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]851<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]852 executed on entrance to the function, and it is not allowed to have
853 predecessor basic blocks (i.e. there can not be any branches to the entry
854 block of a function). Because the block can have no predecessors, it also
855 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]856
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]857<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]859
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]860<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]861 the alignment is set to zero, the alignment of the function is set by the
862 target to whatever it feels convenient. If an explicit alignment is
863 specified, the function is forced to have at least that much alignment. All
864 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]865
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]866<h5>Syntax:</h5>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]867<div class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]869define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]870 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
871 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
872 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
873 [<a href="#gc">gc</a>] { ... }
874</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]875</div>
876
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]877</div>
878
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]879<!-- ======================================================================= -->
880<div class="doc_subsection">
881 <a name="aliasstructure">Aliases</a>
882</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]883
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]884<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]885
886<p>Aliases act as "second name" for the aliasee value (which can be either
887 function, global variable, another alias or bitcast of global value). Aliases
888 may have an optional <a href="#linkage">linkage type</a>, and an
889 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]890
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]892<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]893<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]894@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]895</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]896</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]897
898</div>
899
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]900<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]901<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]902
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]903<div class="doc_text">
904
905<p>The return type and each parameter of a function type may have a set of
906 <i>parameter attributes</i> associated with them. Parameter attributes are
907 used to communicate additional information about the result or parameters of
908 a function. Parameter attributes are considered to be part of the function,
909 not of the function type, so functions with different parameter attributes
910 can have the same function type.</p>
911
912<p>Parameter attributes are simple keywords that follow the type specified. If
913 multiple parameter attributes are needed, they are space separated. For
914 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]915
916<div class="doc_code">
917<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]918declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]919declare i32 @atoi(i8 zeroext)
920declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]921</pre>
922</div>
923
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]924<p>Note that any attributes for the function result (<tt>nounwind</tt>,
925 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]926
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]927<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]928
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]929<dl>
930 <dt><tt>zeroext</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]931 <dd>This indicates to the code generator that the parameter or return value
932 should be zero-extended to a 32-bit value by the caller (for a parameter)
933 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]935 <dt><tt>signext</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be sign-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]940 <dt><tt>inreg</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates that this parameter or return value should be treated in a
942 special target-dependent fashion during while emitting code for a function
943 call or return (usually, by putting it in a register as opposed to memory,
944 though some targets use it to distinguish between two different kinds of
945 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]947 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that the pointer parameter should really be passed by value
949 to the function. The attribute implies that a hidden copy of the pointee
950 is made between the caller and the callee, so the callee is unable to
951 modify the value in the callee. This attribute is only valid on LLVM
952 pointer arguments. It is generally used to pass structs and arrays by
953 value, but is also valid on pointers to scalars. The copy is considered
954 to belong to the caller not the callee (for example,
955 <tt><a href="#readonly">readonly</a></tt> functions should not write to
956 <tt>byval</tt> parameters). This is not a valid attribute for return
957 values. The byval attribute also supports specifying an alignment with
958 the align attribute. This has a target-specific effect on the code
959 generator that usually indicates a desired alignment for the synthesized
960 stack slot.</dd>
961
962 <dt><tt>sret</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter specifies the address of a
964 structure that is the return value of the function in the source program.
965 This pointer must be guaranteed by the caller to be valid: loads and
966 stores to the structure may be assumed by the callee to not to trap. This
967 may only be applied to the first parameter. This is not a valid attribute
968 for return values. </dd>
969
970 <dt><tt>noalias</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer does not alias any global or any other
972 parameter. The caller is responsible for ensuring that this is the
973 case. On a function return value, <tt>noalias</tt> additionally indicates
974 that the pointer does not alias any other pointers visible to the
975 caller. For further details, please see the discussion of the NoAlias
976 response in
977 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
978 analysis</a>.</dd>
979
980 <dt><tt>nocapture</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the callee does not make any copies of the pointer
982 that outlive the callee itself. This is not a valid attribute for return
983 values.</dd>
984
985 <dt><tt>nest</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the pointer parameter can be excised using the
987 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
988 attribute for return values.</dd>
989</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]990
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]991</div>
992
993<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]994<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]995 <a name="gc">Garbage Collector Names</a>
996</div>
997
998<div class="doc_text">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1000<p>Each function may specify a garbage collector name, which is simply a
1001 string:</p>
1002
1003<div class="doc_code">
1004<pre>
1005define void @f() gc "name" { ...
1006</pre>
1007</div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1008
1009<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1010 collector which will cause the compiler to alter its output in order to
1011 support the named garbage collection algorithm.</p>
1012
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1017 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1018</div>
1019
1020<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1021
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1022<p>Function attributes are set to communicate additional information about a
1023 function. Function attributes are considered to be part of the function, not
1024 of the function type, so functions with different parameter attributes can
1025 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are simple keywords that follow the type specified. If
1028 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1029
1030<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1031<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1032define void @f() noinline { ... }
1033define void @f() alwaysinline { ... }
1034define void @f() alwaysinline optsize { ... }
1035define void @f() optsize
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1036</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1037</div>
1038
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1039<dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should attempt to inline this
1042 function into callers whenever possible, ignoring any active inlining size
1043 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1044
Dale Johannesen2aaf5392009-08-26 01:08:21 +0000[diff] [blame]1045 <dt><tt>inlinehint</tt></dt>
1046 <dd>This attribute indicates that the source code contained a hint that inlining
1047 this function is desirable (such as the "inline" keyword in C/C++). It
1048 is just a hint; it imposes no requirements on the inliner.</dd>
1049
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noinline</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This attribute indicates that the inliner should never inline this
1052 function in any situation. This attribute may not be used together with
1053 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1054
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>optsize</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute suggests that optimization passes and code generator passes
1057 make choices that keep the code size of this function low, and otherwise
1058 do optimizations specifically to reduce code size.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>noreturn</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This function attribute indicates that the function never returns
1062 normally. This produces undefined behavior at runtime if the function
1063 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1064
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1065 <dt><tt>nounwind</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns with an
1067 unwind or exceptional control flow. If the function does unwind, its
1068 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1069
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1070 <dt><tt>readnone</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This attribute indicates that the function computes its result (or decides
1072 to unwind an exception) based strictly on its arguments, without
1073 dereferencing any pointer arguments or otherwise accessing any mutable
1074 state (e.g. memory, control registers, etc) visible to caller functions.
1075 It does not write through any pointer arguments
1076 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1077 changes any state visible to callers. This means that it cannot unwind
1078 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1079 could use the <tt>unwind</tt> instruction.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1080
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1081 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the function does not write through any
1083 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1084 arguments) or otherwise modify any state (e.g. memory, control registers,
1085 etc) visible to caller functions. It may dereference pointer arguments
1086 and read state that may be set in the caller. A readonly function always
1087 returns the same value (or unwinds an exception identically) when called
1088 with the same set of arguments and global state. It cannot unwind an
1089 exception by calling the <tt>C++</tt> exception throwing methods, but may
1090 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1091
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This attribute indicates that the function should emit a stack smashing
1094 protector. It is in the form of a "canary"&mdash;a random value placed on
1095 the stack before the local variables that's checked upon return from the
1096 function to see if it has been overwritten. A heuristic is used to
1097 determine if a function needs stack protectors or not.<br>
1098<br>
1099 If a function that has an <tt>ssp</tt> attribute is inlined into a
1100 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1101 function will have an <tt>ssp</tt> attribute.</dd>
1102
1103 <dt><tt>sspreq</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the function should <em>always</em> emit a
1105 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1106 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1107<br>
1108 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1109 function that doesn't have an <tt>sspreq</tt> attribute or which has
1110 an <tt>ssp</tt> attribute, then the resulting function will have
1111 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1112
1113 <dt><tt>noredzone</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1114 <dd>This attribute indicates that the code generator should not use a red
1115 zone, even if the target-specific ABI normally permits it.</dd>
1116
1117 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attributes disables implicit floating point instructions.</dd>
1119
1120 <dt><tt>naked</tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute disables prologue / epilogue emission for the function.
1122 This can have very system-specific consequences.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1123</dl>
1124
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1129 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1130</div>
1131
1132<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133
1134<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1135 the GCC "file scope inline asm" blocks. These blocks are internally
1136 concatenated by LLVM and treated as a single unit, but may be separated in
1137 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1138
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1139<div class="doc_code">
1140<pre>
1141module asm "inline asm code goes here"
1142module asm "more can go here"
1143</pre>
1144</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1145
1146<p>The strings can contain any character by escaping non-printable characters.
1147 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]1148 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1149
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1150<p>The inline asm code is simply printed to the machine code .s file when
1151 assembly code is generated.</p>
1152
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1153</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1154
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="datalayout">Data Layout</a>
1158</div>
1159
1160<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1161
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1162<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1163 data is to be laid out in memory. The syntax for the data layout is
1164 simply:</p>
1165
1166<div class="doc_code">
1167<pre>
1168target datalayout = "<i>layout specification</i>"
1169</pre>
1170</div>
1171
1172<p>The <i>layout specification</i> consists of a list of specifications
1173 separated by the minus sign character ('-'). Each specification starts with
1174 a letter and may include other information after the letter to define some
1175 aspect of the data layout. The specifications accepted are as follows:</p>
1176
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1177<dl>
1178 <dt><tt>E</tt></dt>
1179 <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]1180 bits with the most significance have the lowest address location.</dd>
1181
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1182 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1183 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1184 the bits with the least significance have the lowest address
1185 location.</dd>
1186
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1187 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <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]1189 <i>preferred</i> alignments. All sizes are in bits. Specifying
1190 the <i>pref</i> alignment is optional. If omitted, the
1191 preceding <tt>:</tt> should be omitted too.</dd>
1192
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1193 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1195 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1196
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1197 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1198 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1199 <i>size</i>.</dd>
1200
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1201 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1204 (double).</dd>
1205
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1206 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>.</dd>
1209
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1210 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1211 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1212 <i>size</i>.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1213</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1214
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1215<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1216 default set of specifications which are then (possibly) overriden by the
1217 specifications in the <tt>datalayout</tt> keyword. The default specifications
1218 are given in this list:</p>
1219
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1220<ul>
1221 <li><tt>E</tt> - big endian</li>
1222 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1223 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1224 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1225 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1226 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1227 <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]1228 alignment of 64-bits</li>
1229 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1230 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1231 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1232 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1233 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1234 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1235</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1236
1237<p>When LLVM is determining the alignment for a given type, it uses the
1238 following rules:</p>
1239
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1240<ol>
1241 <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]1242 specification is used.</li>
1243
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1244 <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]1245 smallest integer type that is larger than the bitwidth of the sought type
1246 is used. If none of the specifications are larger than the bitwidth then
1247 the the largest integer type is used. For example, given the default
1248 specifications above, the i7 type will use the alignment of i8 (next
1249 largest) while both i65 and i256 will use the alignment of i64 (largest
1250 specified).</li>
1251
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1252 <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]1253 largest vector type that is smaller than the sought vector type will be
1254 used as a fall back. This happens because &lt;128 x double&gt; can be
1255 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1256</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1257
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1258</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1259
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1260<!-- ======================================================================= -->
1261<div class="doc_subsection">
1262 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1263</div>
1264
1265<div class="doc_text">
1266
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1267<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1268with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1269is undefined. Pointer values are associated with address ranges
1270according to the following rules:</p>
1271
1272<ul>
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1273 <li>A pointer value formed from a
1274 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1275 is associated with the addresses associated with the first operand
1276 of the <tt>getelementptr</tt>.</li>
1277 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1278 range of the variable's storage.</li>
1279 <li>The result value of an allocation instruction is associated with
1280 the address range of the allocated storage.</li>
1281 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1282 no address.</li>
1283 <li>A pointer value formed by an
1284 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1285 address ranges of all pointer values that contribute (directly or
1286 indirectly) to the computation of the pointer's value.</li>
1287 <li>The result value of a
1288 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1289 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1290 <li>An integer constant other than zero or a pointer value returned
1291 from a function not defined within LLVM may be associated with address
1292 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1293 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1294 allocated by mechanisms provided by LLVM.</li>
1295 </ul>
1296
1297<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1298<tt><a href="#i_load">load</a></tt> merely indicates the size and
1299alignment of the memory from which to load, as well as the
1300interpretation of the value. The first operand of a
1301<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1302and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1303
1304<p>Consequently, type-based alias analysis, aka TBAA, aka
1305<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1306LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1307additional information which specialized optimization passes may use
1308to implement type-based alias analysis.</p>
1309
1310</div>
1311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1312<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1313<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1314<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1315
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1316<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1317
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1318<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1319 intermediate representation. Being typed enables a number of optimizations
1320 to be performed on the intermediate representation directly, without having
1321 to do extra analyses on the side before the transformation. A strong type
1322 system makes it easier to read the generated code and enables novel analyses
1323 and transformations that are not feasible to perform on normal three address
1324 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1325
1326</div>
1327
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1328<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1329<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1330Classifications</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1331
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1332<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1335
1336<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1337 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1338 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1339 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1340 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1341 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1342 </tr>
1343 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1344 <td><a href="#t_floating">floating point</a></td>
1345 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1346 </tr>
1347 <tr>
1348 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_integer">integer</a>,
1350 <a href="#t_floating">floating point</a>,
1351 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1352 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1353 <a href="#t_struct">structure</a>,
1354 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1355 <a href="#t_label">label</a>,
1356 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1357 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1358 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1359 <tr>
1360 <td><a href="#t_primitive">primitive</a></td>
1361 <td><a href="#t_label">label</a>,
1362 <a href="#t_void">void</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_floating">floating point</a>,
1364 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1365 </tr>
1366 <tr>
1367 <td><a href="#t_derived">derived</a></td>
1368 <td><a href="#t_integer">integer</a>,
1369 <a href="#t_array">array</a>,
1370 <a href="#t_function">function</a>,
1371 <a href="#t_pointer">pointer</a>,
1372 <a href="#t_struct">structure</a>,
1373 <a href="#t_pstruct">packed structure</a>,
1374 <a href="#t_vector">vector</a>,
1375 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1376 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1378 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1379</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1380
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1381<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1382 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1383 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1384
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1385</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1387<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1388<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1389
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1392<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1393 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1394
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1395</div>
1396
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1398<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1399
1400<div class="doc_text">
1401
1402<h5>Overview:</h5>
1403<p>The integer type is a very simple type that simply specifies an arbitrary
1404 bit width for the integer type desired. Any bit width from 1 bit to
1405 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1406
1407<h5>Syntax:</h5>
1408<pre>
1409 iN
1410</pre>
1411
1412<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1413 value.</p>
1414
1415<h5>Examples:</h5>
1416<table class="layout">
1417 <tr class="layout">
1418 <td class="left"><tt>i1</tt></td>
1419 <td class="left">a single-bit integer.</td>
1420 </tr>
1421 <tr class="layout">
1422 <td class="left"><tt>i32</tt></td>
1423 <td class="left">a 32-bit integer.</td>
1424 </tr>
1425 <tr class="layout">
1426 <td class="left"><tt>i1942652</tt></td>
1427 <td class="left">a really big integer of over 1 million bits.</td>
1428 </tr>
1429</table>
1430
1431<p>Note that the code generator does not yet support large integer types to be
1432 used as function return types. The specific limit on how large a return type
1433 the code generator can currently handle is target-dependent; currently it's
1434 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1435
1436</div>
1437
1438<!-- _______________________________________________________________________ -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1439<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1440
1441<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1442
1443<table>
1444 <tbody>
1445 <tr><th>Type</th><th>Description</th></tr>
1446 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1447 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1448 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1449 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1450 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1451 </tbody>
1452</table>
1453
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1454</div>
1455
1456<!-- _______________________________________________________________________ -->
1457<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1458
1459<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1460
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1461<h5>Overview:</h5>
1462<p>The void type does not represent any value and has no size.</p>
1463
1464<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1465<pre>
1466 void
1467</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1468
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1469</div>
1470
1471<!-- _______________________________________________________________________ -->
1472<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1473
1474<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1475
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1476<h5>Overview:</h5>
1477<p>The label type represents code labels.</p>
1478
1479<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1480<pre>
1481 label
1482</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1483
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1484</div>
1485
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1486<!-- _______________________________________________________________________ -->
1487<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1488
1489<div class="doc_text">
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1490
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1491<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1492<p>The metadata type represents embedded metadata. No derived types may be
1493 created from metadata except for <a href="#t_function">function</a>
1494 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1495
1496<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1497<pre>
1498 metadata
1499</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1500
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1501</div>
1502
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1503
1504<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1505<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1506
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1507<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1508
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1509<p>The real power in LLVM comes from the derived types in the system. This is
1510 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1511 useful types. Each of these types contain one or more element types which
1512 may be a primitive type, or another derived type. For example, it is
1513 possible to have a two dimensional array, using an array as the element type
1514 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1515
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1516</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1517
1518<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1519<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1520
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1521<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1522
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1523<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1524<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1525 sequentially in memory. The array type requires a size (number of elements)
1526 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1527
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1528<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1529<pre>
1530 [&lt;# elements&gt; x &lt;elementtype&gt;]
1531</pre>
1532
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1533<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1534 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1535
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1536<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1537<table class="layout">
1538 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1539 <td class="left"><tt>[40 x i32]</tt></td>
1540 <td class="left">Array of 40 32-bit integer values.</td>
1541 </tr>
1542 <tr class="layout">
1543 <td class="left"><tt>[41 x i32]</tt></td>
1544 <td class="left">Array of 41 32-bit integer values.</td>
1545 </tr>
1546 <tr class="layout">
1547 <td class="left"><tt>[4 x i8]</tt></td>
1548 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1549 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1550</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1551<p>Here are some examples of multidimensional arrays:</p>
1552<table class="layout">
1553 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1554 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1555 <td class="left">3x4 array of 32-bit integer values.</td>
1556 </tr>
1557 <tr class="layout">
1558 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1559 <td class="left">12x10 array of single precision floating point values.</td>
1560 </tr>
1561 <tr class="layout">
1562 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1563 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1564 </tr>
1565</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1566
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1567<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1568 length array. Normally, accesses past the end of an array are undefined in
1569 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1570 a special case, however, zero length arrays are recognized to be variable
1571 length. This allows implementation of 'pascal style arrays' with the LLVM
1572 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1573
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1574<p>Note that the code generator does not yet support large aggregate types to be
1575 used as function return types. The specific limit on how large an aggregate
1576 return type the code generator can currently handle is target-dependent, and
1577 also dependent on the aggregate element types.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1578
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1579</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1580
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1581<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1582<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1583
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1584<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1585
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1586<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1587<p>The function type can be thought of as a function signature. It consists of
1588 a return type and a list of formal parameter types. The return type of a
1589 function type is a scalar type, a void type, or a struct type. If the return
1590 type is a struct type then all struct elements must be of first class types,
1591 and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1592
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1593<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1594<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1595 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1596</pre>
1597
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1598<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]1599 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1600 which indicates that the function takes a variable number of arguments.
1601 Variable argument functions can access their arguments with
1602 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1603 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1604 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1605
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1606<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1607<table class="layout">
1608 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1609 <td class="left"><tt>i32 (i32)</tt></td>
1610 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1611 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1612 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1613 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1614 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1615 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1616 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1617 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1618 <tt>float</tt>.
1619 </td>
1620 </tr><tr class="layout">
1621 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1622 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1623 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1624 which returns an integer. This is the signature for <tt>printf</tt> in
1625 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1626 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1627 </tr><tr class="layout">
1628 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]1629 <td class="left">A function taking an <tt>i32</tt>, returning a
1630 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1631 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1632 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1633</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1634
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1635</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1636
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1637<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1638<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1639
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1640<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1641
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1642<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1643<p>The structure type is used to represent a collection of data members together
1644 in memory. The packing of the field types is defined to match the ABI of the
1645 underlying processor. The elements of a structure may be any type that has a
1646 size.</p>
1647
1648<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1649 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1650 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1651
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1652<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1653<pre>
1654 { &lt;type list&gt; }
1655</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1656
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1657<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1658<table class="layout">
1659 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1660 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1661 <td class="left">A triple of three <tt>i32</tt> values</td>
1662 </tr><tr class="layout">
1663 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1664 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1665 second element is a <a href="#t_pointer">pointer</a> to a
1666 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1667 an <tt>i32</tt>.</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>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1670
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1671<p>Note that the code generator does not yet support large aggregate types to be
1672 used as function return types. The specific limit on how large an aggregate
1673 return type the code generator can currently handle is target-dependent, and
1674 also dependent on the aggregate element types.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1675
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1676</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1677
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1678<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1679<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1680</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1681
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1682<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1683
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1684<h5>Overview:</h5>
1685<p>The packed structure type is used to represent a collection of data members
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1686 together in memory. There is no padding between fields. Further, the
1687 alignment of a packed structure is 1 byte. The elements of a packed
1688 structure may be any type that has a size.</p>
1689
1690<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1691 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1692 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1693
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1694<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1695<pre>
1696 &lt; { &lt;type list&gt; } &gt;
1697</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1698
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1699<h5>Examples:</h5>
1700<table class="layout">
1701 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1702 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1703 <td class="left">A triple of three <tt>i32</tt> values</td>
1704 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1705 <td class="left">
1706<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1707 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1708 second element is a <a href="#t_pointer">pointer</a> to a
1709 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1710 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1711 </tr>
1712</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1713
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1714</div>
1715
1716<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1717<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1718
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1719<div class="doc_text">
1720
1721<h5>Overview:</h5>
1722<p>As in many languages, the pointer type represents a pointer or reference to
1723 another object, which must live in memory. Pointer types may have an optional
1724 address space attribute defining the target-specific numbered address space
1725 where the pointed-to object resides. The default address space is zero.</p>
1726
1727<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1728 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]1729
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1730<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1731<pre>
1732 &lt;type&gt; *
1733</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1734
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1735<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1736<table class="layout">
1737 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]1738 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1739 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1740 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1741 </tr>
1742 <tr class="layout">
1743 <td class="left"><tt>i32 (i32 *) *</tt></td>
1744 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1745 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1746 <tt>i32</tt>.</td>
1747 </tr>
1748 <tr class="layout">
1749 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1750 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1751 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1752 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1754
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1755</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1756
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1757<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1758<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1759
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1760<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1761
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1762<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1763<p>A vector type is a simple derived type that represents a vector of elements.
1764 Vector types are used when multiple primitive data are operated in parallel
1765 using a single instruction (SIMD). A vector type requires a size (number of
1766 elements) and an underlying primitive data type. Vectors must have a power
1767 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1768 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1769
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1770<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1771<pre>
1772 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1773</pre>
1774
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1775<p>The number of elements is a constant integer value; elementtype may be any
1776 integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1777
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1778<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1779<table class="layout">
1780 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1781 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1782 <td class="left">Vector of 4 32-bit integer values.</td>
1783 </tr>
1784 <tr class="layout">
1785 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1786 <td class="left">Vector of 8 32-bit floating-point values.</td>
1787 </tr>
1788 <tr class="layout">
1789 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1790 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1791 </tr>
1792</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1793
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1794<p>Note that the code generator does not yet support large vector types to be
1795 used as function return types. The specific limit on how large a vector
1796 return type codegen can currently handle is target-dependent; currently it's
1797 often a few times longer than a hardware vector register.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1798
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1799</div>
1800
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
1802<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1803<div class="doc_text">
1804
1805<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1806<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1807 corresponds (for example) to the C notion of a forward declared structure
1808 type. In LLVM, opaque types can eventually be resolved to any type (not just
1809 a structure type).</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1810
1811<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1812<pre>
1813 opaque
1814</pre>
1815
1816<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1817<table class="layout">
1818 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1819 <td class="left"><tt>opaque</tt></td>
1820 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1821 </tr>
1822</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1823
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1824</div>
1825
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1826<!-- ======================================================================= -->
1827<div class="doc_subsection">
1828 <a name="t_uprefs">Type Up-references</a>
1829</div>
1830
1831<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1832
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1833<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1834<p>An "up reference" allows you to refer to a lexically enclosing type without
1835 requiring it to have a name. For instance, a structure declaration may
1836 contain a pointer to any of the types it is lexically a member of. Example
1837 of up references (with their equivalent as named type declarations)
1838 include:</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1839
1840<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +0000[diff] [blame]1841 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1842 { \2 }* %y = type { %y }*
1843 \1* %z = type %z*
1844</pre>
1845
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1846<p>An up reference is needed by the asmprinter for printing out cyclic types
1847 when there is no declared name for a type in the cycle. Because the
1848 asmprinter does not want to print out an infinite type string, it needs a
1849 syntax to handle recursive types that have no names (all names are optional
1850 in llvm IR).</p>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1851
1852<h5>Syntax:</h5>
1853<pre>
1854 \&lt;level&gt;
1855</pre>
1856
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1857<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]1858
1859<h5>Examples:</h5>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1860<table class="layout">
1861 <tr class="layout">
1862 <td class="left"><tt>\1*</tt></td>
1863 <td class="left">Self-referential pointer.</td>
1864 </tr>
1865 <tr class="layout">
1866 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1867 <td class="left">Recursive structure where the upref refers to the out-most
1868 structure.</td>
1869 </tr>
1870</table>
Chris Lattnercf7a5842009-02-02 07:32:36 +0000[diff] [blame]1871
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1872</div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1873
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1874<!-- *********************************************************************** -->
1875<div class="doc_section"> <a name="constants">Constants</a> </div>
1876<!-- *********************************************************************** -->
1877
1878<div class="doc_text">
1879
1880<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1881 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1882
1883</div>
1884
1885<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1886<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1887
1888<div class="doc_text">
1889
1890<dl>
1891 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1892 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1893 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1894
1895 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1896 <dd>Standard integers (such as '4') are constants of
1897 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1898 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1899
1900 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1901 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1902 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1903 notation (see below). The assembler requires the exact decimal value of a
1904 floating-point constant. For example, the assembler accepts 1.25 but
1905 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1906 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1907
1908 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1909 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1910 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1911</dl>
1912
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1913<p>The one non-intuitive notation for constants is the hexadecimal form of
1914 floating point constants. For example, the form '<tt>double
1915 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1916 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1917 constants are required (and the only time that they are generated by the
1918 disassembler) is when a floating point constant must be emitted but it cannot
1919 be represented as a decimal floating point number in a reasonable number of
1920 digits. For example, NaN's, infinities, and other special values are
1921 represented in their IEEE hexadecimal format so that assembly and disassembly
1922 do not cause any bits to change in the constants.</p>
1923
Dale Johannesencd4a3012009-02-11 22:14:51 +0000[diff] [blame]1924<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1925 represented using the 16-digit form shown above (which matches the IEEE754
1926 representation for double); float values must, however, be exactly
1927 representable as IEE754 single precision. Hexadecimal format is always used
1928 for long double, and there are three forms of long double. The 80-bit format
1929 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1930 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1931 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1932 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1933 currently supported target uses this format. Long doubles will only work if
1934 they match the long double format on your target. All hexadecimal formats
1935 are big-endian (sign bit at the left).</p>
1936
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1937</div>
1938
1939<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]1940<div class="doc_subsection">
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]1941<a name="aggregateconstants"></a> <!-- old anchor -->
1942<a name="complexconstants">Complex Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1943</div>
1944
1945<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1946
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]1947<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1948 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1949
1950<dl>
1951 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1952 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1953 type definitions (a comma separated list of elements, surrounded by braces
1954 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1955 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1956 Structure constants must have <a href="#t_struct">structure type</a>, and
1957 the number and types of elements must match those specified by the
1958 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1959
1960 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1961 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1962 definitions (a comma separated list of elements, surrounded by square
1963 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1964 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1967
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1968 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1969 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by
1971 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1972 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1973 have <a href="#t_vector">vector type</a>, and the number and types of
1974 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1975
1976 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1977 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1978 value to zero of <em>any</em> type, including scalar and aggregate types.
1979 This is often used to avoid having to print large zero initializers
1980 (e.g. for large arrays) and is always exactly equivalent to using explicit
1981 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]1982
1983 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]1984 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1985 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1986 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1987 be interpreted as part of the instruction stream, metadata is a place to
1988 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1989</dl>
1990
1991</div>
1992
1993<!-- ======================================================================= -->
1994<div class="doc_subsection">
1995 <a name="globalconstants">Global Variable and Function Addresses</a>
1996</div>
1997
1998<div class="doc_text">
1999
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2000<p>The addresses of <a href="#globalvars">global variables</a>
2001 and <a href="#functionstructure">functions</a> are always implicitly valid
2002 (link-time) constants. These constants are explicitly referenced when
2003 the <a href="#identifiers">identifier for the global</a> is used and always
2004 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2005 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2006
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2007<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2008<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2009@X = global i32 17
2010@Y = global i32 42
2011@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2012</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2013</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2014
2015</div>
2016
2017<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]2018<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2019<div class="doc_text">
2020
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2021<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
2022 indicates that the user of the value may recieve an unspecified bit-pattern.
2023 Undefined values may be of any type (other than label or void) and be used
2024 anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2025
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2026<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2027 program is well defined no matter what value is used. This gives the
2028 compiler more freedom to optimize. Here are some examples of (potentially
2029 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2030
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2031
2032<div class="doc_code">
2033<pre>
2034 %A = add %X, undef
2035 %B = sub %X, undef
2036 %C = xor %X, undef
2037Safe:
2038 %A = undef
2039 %B = undef
2040 %C = undef
2041</pre>
2042</div>
2043
2044<p>This is safe because all of the output bits are affected by the undef bits.
2045Any output bit can have a zero or one depending on the input bits.</p>
2046
2047<div class="doc_code">
2048<pre>
2049 %A = or %X, undef
2050 %B = and %X, undef
2051Safe:
2052 %A = -1
2053 %B = 0
2054Unsafe:
2055 %A = undef
2056 %B = undef
2057</pre>
2058</div>
2059
2060<p>These logical operations have bits that are not always affected by the input.
2061For example, if "%X" has a zero bit, then the output of the 'and' operation will
2062always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2063such, it is unsafe to optimize or assume that the result of the and is undef.
2064However, it is safe to assume that all bits of the undef could be 0, and
2065optimize the and to 0. Likewise, it is safe to assume that all the bits of
2066the undef operand to the or could be set, allowing the or to be folded to
2067-1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2068
2069<div class="doc_code">
2070<pre>
2071 %A = select undef, %X, %Y
2072 %B = select undef, 42, %Y
2073 %C = select %X, %Y, undef
2074Safe:
2075 %A = %X (or %Y)
2076 %B = 42 (or %Y)
2077 %C = %Y
2078Unsafe:
2079 %A = undef
2080 %B = undef
2081 %C = undef
2082</pre>
2083</div>
2084
2085<p>This set of examples show that undefined select (and conditional branch)
2086conditions can go "either way" but they have to come from one of the two
2087operands. In the %A example, if %X and %Y were both known to have a clear low
2088bit, then %A would have to have a cleared low bit. However, in the %C example,
2089the optimizer is allowed to assume that the undef operand could be the same as
2090%Y, allowing the whole select to be eliminated.</p>
2091
2092
2093<div class="doc_code">
2094<pre>
2095 %A = xor undef, undef
2096
2097 %B = undef
2098 %C = xor %B, %B
2099
2100 %D = undef
2101 %E = icmp lt %D, 4
2102 %F = icmp gte %D, 4
2103
2104Safe:
2105 %A = undef
2106 %B = undef
2107 %C = undef
2108 %D = undef
2109 %E = undef
2110 %F = undef
2111</pre>
2112</div>
2113
2114<p>This example points out that two undef operands are not necessarily the same.
2115This can be surprising to people (and also matches C semantics) where they
2116assume that "X^X" is always zero, even if X is undef. This isn't true for a
2117number of reasons, but the short answer is that an undef "variable" can
2118arbitrarily change its value over its "live range". This is true because the
2119"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2120logically read from arbitrary registers that happen to be around when needed,
2121so the value is not neccesarily consistent over time. In fact, %A and %C need
Chris Lattner6760e542009-09-08 15:13:16 +0000[diff] [blame]2122to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2123would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2124
2125<div class="doc_code">
2126<pre>
2127 %A = fdiv undef, %X
2128 %B = fdiv %X, undef
2129Safe:
2130 %A = undef
2131b: unreachable
2132</pre>
2133</div>
2134
2135<p>These examples show the crucial difference between an <em>undefined
2136value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2137allowed to have an arbitrary bit-pattern. This means that the %A operation
2138can be constant folded to undef because the undef could be an SNaN, and fdiv is
2139not (currently) defined on SNaN's. However, in the second example, we can make
2140a more aggressive assumption: because the undef is allowed to be an arbitrary
2141value, 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]2142has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2143does not execute at all. This allows us to delete the divide and all code after
2144it: since the undefined operation "can't happen", the optimizer can assume that
2145it occurs in dead code.
2146</p>
2147
2148<div class="doc_code">
2149<pre>
2150a: store undef -> %X
2151b: store %X -> undef
2152Safe:
2153a: &lt;deleted&gt;
2154b: unreachable
2155</pre>
2156</div>
2157
2158<p>These examples reiterate the fdiv example: a store "of" an undefined value
2159can be assumed to not have any effect: we can assume that the value is
2160overwritten with bits that happen to match what was already there. However, a
2161store "to" an undefined location could clobber arbitrary memory, therefore, it
2162has undefined behavior.</p>
2163
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2164</div>
2165
2166<!-- ======================================================================= -->
2167<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2168</div>
2169
2170<div class="doc_text">
2171
2172<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2173 to be used as constants. Constant expressions may be of
2174 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2175 operation that does not have side effects (e.g. load and call are not
2176 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2177
2178<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2179 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2180 <dd>Truncate a constant to another type. The bit size of CST must be larger
2181 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2182
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2183 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2184 <dd>Zero extend a constant to another type. The bit size of CST must be
2185 smaller or equal to the bit size of TYPE. Both types must be
2186 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2187
2188 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2189 <dd>Sign extend a constant to another type. The bit size of CST must be
2190 smaller or equal to the bit size of TYPE. Both types must be
2191 integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2192
2193 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2194 <dd>Truncate a floating point constant to another floating point type. The
2195 size of CST must be larger than the size of TYPE. Both types must be
2196 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2197
2198 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2199 <dd>Floating point extend a constant to another type. The size of CST must be
2200 smaller or equal to the size of TYPE. Both types must be floating
2201 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2202
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]2203 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2204 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2205 constant. TYPE must be a scalar or vector integer type. CST must be of
2206 scalar or vector floating point type. Both CST and TYPE must be scalars,
2207 or vectors of the same number of elements. If the value won't fit in the
2208 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2209
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2210 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2211 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2212 constant. TYPE must be a scalar or vector integer type. CST must be of
2213 scalar or vector floating point type. Both CST and TYPE must be scalars,
2214 or vectors of the same number of elements. If the value won't fit in the
2215 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2216
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2217 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2218 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2219 constant. TYPE must be a scalar or vector floating point type. CST must be
2220 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2221 vectors of the same number of elements. If the value won't fit in the
2222 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2223
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2224 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2225 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2226 constant. TYPE must be a scalar or vector floating point type. CST must be
2227 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2228 vectors of the same number of elements. If the value won't fit in the
2229 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2230
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2231 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2232 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2233 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2234 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2235 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2236
2237 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2238 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2239 type. CST must be of integer type. The CST value is zero extended,
2240 truncated, or unchanged to make it fit in a pointer size. This one is
2241 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2242
2243 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2244 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2245 are the same as those for the <a href="#i_bitcast">bitcast
2246 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2247
2248 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]2249 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2250 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2251 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2252 instruction, the index list may have zero or more indexes, which are
2253 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2254
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2255 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2256 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2257
2258 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2259 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2260
2261 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2262 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2263
2264 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2265 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2266 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2267
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]2268 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2269 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2270 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2271
2272 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2273 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2274 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2275
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2276 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2277 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2278 be any of the <a href="#binaryops">binary</a>
2279 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2280 on operands are the same as those for the corresponding instruction
2281 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2282</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2283
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2284</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2285
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2286<!-- ======================================================================= -->
2287<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2288</div>
2289
2290<div class="doc_text">
2291
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2292<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2293 stream without affecting the behaviour of the program. There are two
2294 metadata primitives, strings and nodes. All metadata has the
2295 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2296 point ('<tt>!</tt>').</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2297
2298<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2299 any character by escaping non-printable characters with "\xx" where "xx" is
2300 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2301
2302<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2303 (a comma separated list of elements, surrounded by braces and preceeded by an
2304 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2305 10}</tt>".</p>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2306
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2307<p>A metadata node will attempt to track changes to the values it holds. In the
2308 event that a value is deleted, it will be replaced with a typeless
2309 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewyckyb8f9b7a2009-05-10 20:57:05 +0000[diff] [blame]2310
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2311<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2312 the program that isn't available in the instructions, or that isn't easily
2313 computable. Similarly, the code generator may expect a certain metadata
2314 format to be used to express debugging information.</p>
2315
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2316</div>
2317
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2318<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2319<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2320<!-- *********************************************************************** -->
2321
2322<!-- ======================================================================= -->
2323<div class="doc_subsection">
2324<a name="inlineasm">Inline Assembler Expressions</a>
2325</div>
2326
2327<div class="doc_text">
2328
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2329<p>LLVM supports inline assembler expressions (as opposed
2330 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2331 a special value. This value represents the inline assembler as a string
2332 (containing the instructions to emit), a list of operand constraints (stored
2333 as a string), and a flag that indicates whether or not the inline asm
2334 expression has side effects. An example inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2335
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2336<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2337<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2338i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2339</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2340</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2341
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2342<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2343 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2344 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2345
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2346<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2347<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2348%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]2349</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2350</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2351
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2352<p>Inline asms with side effects not visible in the constraint list must be
2353 marked as having side effects. This is done through the use of the
2354 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2355
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2356<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2357<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2358call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2359</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2360</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2361
2362<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2363 documented here. Constraints on what can be done (e.g. duplication, moving,
2364 etc need to be documented). This is probably best done by reference to
2365 another document that covers inline asm from a holistic perspective.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2366
2367</div>
2368
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2369
2370<!-- *********************************************************************** -->
2371<div class="doc_section">
2372 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2373</div>
2374<!-- *********************************************************************** -->
2375
2376<p>LLVM has a number of "magic" global variables that contain data that affect
2377code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2378of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2379section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2380by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2381
2382<!-- ======================================================================= -->
2383<div class="doc_subsection">
2384<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2385</div>
2386
2387<div class="doc_text">
2388
2389<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2390href="#linkage_appending">appending linkage</a>. This array contains a list of
2391pointers to global variables and functions which may optionally have a pointer
2392cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2393
2394<pre>
2395 @X = global i8 4
2396 @Y = global i32 123
2397
2398 @llvm.used = appending global [2 x i8*] [
2399 i8* @X,
2400 i8* bitcast (i32* @Y to i8*)
2401 ], section "llvm.metadata"
2402</pre>
2403
2404<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2405compiler, assembler, and linker are required to treat the symbol as if there is
2406a reference to the global that it cannot see. For example, if a variable has
2407internal linkage and no references other than that from the <tt>@llvm.used</tt>
2408list, it cannot be deleted. This is commonly used to represent references from
2409inline asms and other things the compiler cannot "see", and corresponds to
2410"attribute((used))" in GNU C.</p>
2411
2412<p>On some targets, the code generator must emit a directive to the assembler or
2413object file to prevent the assembler and linker from molesting the symbol.</p>
2414
2415</div>
2416
2417<!-- ======================================================================= -->
2418<div class="doc_subsection">
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]2419<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2420</div>
2421
2422<div class="doc_text">
2423
2424<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2425<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2426touching the symbol. On targets that support it, this allows an intelligent
2427linker to optimize references to the symbol without being impeded as it would be
2428by <tt>@llvm.used</tt>.</p>
2429
2430<p>This is a rare construct that should only be used in rare circumstances, and
2431should not be exposed to source languages.</p>
2432
2433</div>
2434
2435<!-- ======================================================================= -->
2436<div class="doc_subsection">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]2437<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2438</div>
2439
2440<div class="doc_text">
2441
2442<p>TODO: Describe this.</p>
2443
2444</div>
2445
2446<!-- ======================================================================= -->
2447<div class="doc_subsection">
2448<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2449</div>
2450
2451<div class="doc_text">
2452
2453<p>TODO: Describe this.</p>
2454
2455</div>
2456
2457
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2458<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2459<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2460<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2461
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2462<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2463
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2464<p>The LLVM instruction set consists of several different classifications of
2465 instructions: <a href="#terminators">terminator
2466 instructions</a>, <a href="#binaryops">binary instructions</a>,
2467 <a href="#bitwiseops">bitwise binary instructions</a>,
2468 <a href="#memoryops">memory instructions</a>, and
2469 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2470
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2471</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2472
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2473<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2474<div class="doc_subsection"> <a name="terminators">Terminator
2475Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2476
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2477<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2478
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2479<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2480 in a program ends with a "Terminator" instruction, which indicates which
2481 block should be executed after the current block is finished. These
2482 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2483 control flow, not values (the one exception being the
2484 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2485
2486<p>There are six different terminator instructions: the
2487 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2488 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2489 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2490 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2491 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2492 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2493
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2494</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2495
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2496<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2497<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2498Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2499
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2500<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2501
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2502<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2503<pre>
2504 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]2505 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2506</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2507
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2508<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2509<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2510 a value) from a function back to the caller.</p>
2511
2512<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2513 value and then causes control flow, and one that just causes control flow to
2514 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2515
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2516<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2517<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2518 return value. The type of the return value must be a
2519 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]2520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2521<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2522 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2523 value or a return value with a type that does not match its type, or if it
2524 has a void return type and contains a '<tt>ret</tt>' instruction with a
2525 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2526
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2527<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2528<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2529 the calling function's context. If the caller is a
2530 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2531 instruction after the call. If the caller was an
2532 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2533 the beginning of the "normal" destination block. If the instruction returns
2534 a value, that value shall set the call or invoke instruction's return
2535 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2536
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2537<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2538<pre>
2539 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2540 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]2541 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]2542</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2543
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2544<p>Note that the code generator does not yet fully support large
2545 return values. The specific sizes that are currently supported are
2546 dependent on the target. For integers, on 32-bit targets the limit
2547 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2548 For aggregate types, the current limits are dependent on the element
2549 types; for example targets are often limited to 2 total integer
2550 elements and 2 total floating-point elements.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]2551
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2552</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2553<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2554<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2555
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2556<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2557
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2559<pre>
2560 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]2561</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2562
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2563<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2564<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2565 different basic block in the current function. There are two forms of this
2566 instruction, corresponding to a conditional branch and an unconditional
2567 branch.</p>
2568
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2569<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2570<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2571 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2572 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2573 target.</p>
2574
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2575<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2576<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2577 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2578 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2579 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2580
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2581<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2582<pre>
2583Test:
2584 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2585 br i1 %cond, label %IfEqual, label %IfUnequal
2586IfEqual:
2587 <a href="#i_ret">ret</a> i32 1
2588IfUnequal:
2589 <a href="#i_ret">ret</a> i32 0
2590</pre>
2591
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2592</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2593
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2594<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2595<div class="doc_subsubsection">
2596 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2597</div>
2598
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2599<div class="doc_text">
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2600
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2601<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2602<pre>
2603 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2604</pre>
2605
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2606<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2607<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]2608 several different places. It is a generalization of the '<tt>br</tt>'
2609 instruction, allowing a branch to occur to one of many possible
2610 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2611
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2612<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2613<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2614 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2615 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2616 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2617
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2618<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2619<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2620 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2621 is searched for the given value. If the value is found, control flow is
2622 transfered to the corresponding destination; otherwise, control flow is
2623 transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2624
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2625<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2626<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2627 <tt>switch</tt> instruction, this instruction may be code generated in
2628 different ways. For example, it could be generated as a series of chained
2629 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2630
2631<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2632<pre>
2633 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2634 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2635 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2636
2637 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2638 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]2639
2640 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2641 switch i32 %val, label %otherwise [ i32 0, label %onzero
2642 i32 1, label %onone
2643 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2644</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2645
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2646</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2647
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2648<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2649<div class="doc_subsubsection">
2650 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2651</div>
2652
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2653<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2654
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2655<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2656<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2657 &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]2658 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2659</pre>
2660
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2661<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2662<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2663 function, with the possibility of control flow transfer to either the
2664 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2665 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2666 control flow will return to the "normal" label. If the callee (or any
2667 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2668 instruction, control is interrupted and continued at the dynamically nearest
2669 "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2670
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2671<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2672<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2673
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2674<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2675 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2676 convention</a> the call should use. If none is specified, the call
2677 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2678
2679 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2680 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2681 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]2682
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2683 <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]2684 function value being invoked. In most cases, this is a direct function
2685 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2686 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2687
2688 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2689 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2690
2691 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2692 signature argument types. If the function signature indicates the
2693 function accepts a variable number of arguments, the extra arguments can
2694 be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2695
2696 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2697 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2698
2699 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2700 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2701
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]2702 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2703 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2704 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2705</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2706
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2707<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2708<p>This instruction is designed to operate as a standard
2709 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2710 primary difference is that it establishes an association with a label, which
2711 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2712
2713<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2714 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2715 exception. Additionally, this is important for implementation of
2716 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2717
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2718<p>For the purposes of the SSA form, the definition of the value returned by the
2719 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2720 block to the "normal" label. If the callee unwinds then no return value is
2721 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]2722
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2723<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2724<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2725 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2726 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2727 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2728 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2729</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2730
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2731</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2732
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2733<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2734
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2735<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2736Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2737
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2738<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2739
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2740<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2741<pre>
2742 unwind
2743</pre>
2744
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2745<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2746<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2747 at the first callee in the dynamic call stack which used
2748 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2749 This is primarily used to implement exception handling.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2750
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2751<h5>Semantics:</h5>
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2752<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2753 immediately halt. The dynamic call stack is then searched for the
2754 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2755 Once found, execution continues at the "exceptional" destination block
2756 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2757 instruction in the dynamic call chain, undefined behavior results.</p>
2758
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2759</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2760
2761<!-- _______________________________________________________________________ -->
2762
2763<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2764Instruction</a> </div>
2765
2766<div class="doc_text">
2767
2768<h5>Syntax:</h5>
2769<pre>
2770 unreachable
2771</pre>
2772
2773<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2774<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2775 instruction is used to inform the optimizer that a particular portion of the
2776 code is not reachable. This can be used to indicate that the code after a
2777 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2778
2779<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2780<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2781
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2782</div>
2783
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2784<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2785<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2787<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2788
2789<p>Binary operators are used to do most of the computation in a program. They
2790 require two operands of the same type, execute an operation on them, and
2791 produce a single value. The operands might represent multiple data, as is
2792 the case with the <a href="#t_vector">vector</a> data type. The result value
2793 has the same type as its operands.</p>
2794
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2795<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2796
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2797</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2798
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2799<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2800<div class="doc_subsubsection">
2801 <a name="i_add">'<tt>add</tt>' Instruction</a>
2802</div>
2803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2804<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2806<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2807<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2808 &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]2809 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2810 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2811 &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]2812</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2813
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2815<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2816
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2817<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2818<p>The two arguments to the '<tt>add</tt>' instruction must
2819 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2820 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2822<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2823<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2824
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2825<p>If the sum has unsigned overflow, the result returned is the mathematical
2826 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]2827
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2828<p>Because LLVM integers use a two's complement representation, this instruction
2829 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2830
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2831<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2832 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2833 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2834 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2835
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2837<pre>
2838 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2839</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2840
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2841</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2842
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2843<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2844<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2845 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2846</div>
2847
2848<div class="doc_text">
2849
2850<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2851<pre>
2852 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2853</pre>
2854
2855<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2856<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2857
2858<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2859<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2860 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2861 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2862
2863<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2864<p>The value produced is the floating point sum of the two operands.</p>
2865
2866<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2867<pre>
2868 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2869</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2871</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2872
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2873<!-- _______________________________________________________________________ -->
2874<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2875 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2876</div>
2877
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2878<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2879
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2880<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2881<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2882 &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]2883 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2884 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2885 &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]2886</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2887
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2888<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2889<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2890 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2891
2892<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2893 '<tt>neg</tt>' instruction present in most other intermediate
2894 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2897<p>The two arguments to the '<tt>sub</tt>' instruction must
2898 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2899 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2900
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2901<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2902<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2903
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2904<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2905 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2906 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2907
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2908<p>Because LLVM integers use a two's complement representation, this instruction
2909 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2910
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2911<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2912 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2913 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2914 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]2915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2916<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2917<pre>
2918 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2919 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2920</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2921
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2922</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2923
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2924<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2925<div class="doc_subsubsection">
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2926 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2927</div>
2928
2929<div class="doc_text">
2930
2931<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2932<pre>
2933 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2934</pre>
2935
2936<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2937<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2938 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2939
2940<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2941 '<tt>fneg</tt>' instruction present in most other intermediate
2942 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2943
2944<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2945<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2946 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2947 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2948
2949<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2950<p>The value produced is the floating point difference of the two operands.</p>
2951
2952<h5>Example:</h5>
2953<pre>
2954 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2955 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2956</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2957
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2958</div>
2959
2960<!-- _______________________________________________________________________ -->
2961<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2962 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2963</div>
2964
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2965<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2966
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2967<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2968<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2969 &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]2970 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2971 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2972 &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]2973</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2974
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2975<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2976<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2978<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2979<p>The two arguments to the '<tt>mul</tt>' instruction must
2980 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2981 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2982
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2983<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]2984<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2985
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2986<p>If the result of the multiplication has unsigned overflow, the result
2987 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2988 width of the result.</p>
2989
2990<p>Because LLVM integers use a two's complement representation, and the result
2991 is the same width as the operands, this instruction returns the correct
2992 result for both signed and unsigned integers. If a full product
2993 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2994 be sign-extended or zero-extended as appropriate to the width of the full
2995 product.</p>
2996
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]2997<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2998 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2999 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3000 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3001
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3002<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3003<pre>
3004 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3005</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3006
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3007</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3009<!-- _______________________________________________________________________ -->
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3010<div class="doc_subsubsection">
3011 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3012</div>
3013
3014<div class="doc_text">
3015
3016<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3017<pre>
3018 &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]3019</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3020
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3021<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3022<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3023
3024<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3025<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3026 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3027 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3028
3029<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3030<p>The value produced is the floating point product of the two operands.</p>
3031
3032<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3033<pre>
3034 &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]3035</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3036
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3037</div>
3038
3039<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3040<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3041</a></div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3042
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3043<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3044
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3045<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3046<pre>
3047 &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]3048</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3049
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3050<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3051<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3052
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3053<h5>Arguments:</h5>
3054<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3055 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3056 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3057
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3058<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3059<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3060
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3061<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3062 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3063
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3064<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3065
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3066<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3067<pre>
3068 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3069</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3070
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3071</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3072
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3073<!-- _______________________________________________________________________ -->
3074<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3075</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3076
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3077<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3078
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3079<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3080<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3081 &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]3082 &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]3083</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3084
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3085<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3086<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3087
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3088<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3089<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3090 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3091 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3092
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3093<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3094<p>The value produced is the signed integer quotient of the two operands rounded
3095 towards zero.</p>
3096
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3097<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3098 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3099
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3100<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3101 undefined behavior; this is a rare case, but can occur, for example, by doing
3102 a 32-bit division of -2147483648 by -1.</p>
3103
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3104<p>If the <tt>exact</tt> keyword is present, the result value of the
3105 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3106 would occur.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3107
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3108<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3109<pre>
3110 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3111</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3112
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3113</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3114
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3115<!-- _______________________________________________________________________ -->
3116<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3117Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3118
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3119<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3120
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3121<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3122<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3123 &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]3124</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3125
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3126<h5>Overview:</h5>
3127<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3128
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3129<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3130<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3131 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3132 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3133
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3134<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3135<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3136
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3137<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3138<pre>
3139 &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]3140</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3141
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3142</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3143
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3144<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3145<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3146</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3147
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3148<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3149
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3150<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3151<pre>
3152 &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]3153</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3154
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3155<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3156<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3157 division of its two arguments.</p>
3158
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3159<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3160<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3161 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3162 values. Both arguments must have identical types.</p>
3163
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3164<h5>Semantics:</h5>
3165<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3166 This instruction always performs an unsigned division to get the
3167 remainder.</p>
3168
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3169<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3170 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3171
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3172<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3173
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3174<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3175<pre>
3176 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3177</pre>
3178
3179</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3180
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3181<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3182<div class="doc_subsubsection">
3183 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3184</div>
3185
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3186<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3187
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3188<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3189<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3190 &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]3191</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3192
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3193<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3194<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3195 division of its two operands. This instruction can also take
3196 <a href="#t_vector">vector</a> versions of the values in which case the
3197 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]3198
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3199<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3200<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3201 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3202 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3203
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3204<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3205<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3206 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3207 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3208 a value. For more information about the difference,
3209 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3210 Math Forum</a>. For a table of how this is implemented in various languages,
3211 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3212 Wikipedia: modulo operation</a>.</p>
3213
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3214<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3215 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3216
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3217<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3218 Overflow also leads to undefined behavior; this is a rare case, but can
3219 occur, for example, by taking the remainder of a 32-bit division of
3220 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3221 lets srem be implemented using instructions that return both the result of
3222 the division and the remainder.)</p>
3223
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3224<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3225<pre>
3226 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3227</pre>
3228
3229</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3230
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3231<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3232<div class="doc_subsubsection">
3233 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3234
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3235<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3236
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3237<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3238<pre>
3239 &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]3240</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3241
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3242<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3243<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3244 its two operands.</p>
3245
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3246<h5>Arguments:</h5>
3247<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3248 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3249 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3250
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3251<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3252<p>This instruction returns the <i>remainder</i> of a division. The remainder
3253 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3254
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]3255<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3256<pre>
3257 &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]3258</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3259
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3260</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]3261
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3262<!-- ======================================================================= -->
3263<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3264Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3265
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3266<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3267
3268<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3269 program. They are generally very efficient instructions and can commonly be
3270 strength reduced from other instructions. They require two operands of the
3271 same type, execute an operation on them, and produce a single value. The
3272 resulting value is the same type as its operands.</p>
3273
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3274</div>
3275
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3276<!-- _______________________________________________________________________ -->
3277<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3278Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3279
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3280<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3281
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3282<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3283<pre>
3284 &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]3285</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3286
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3287<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3288<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3289 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3290
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3291<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3292<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3293 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3294 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3295
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3296<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3297<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3298 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3299 is (statically or dynamically) negative or equal to or larger than the number
3300 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3301 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3302 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3303
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3304<h5>Example:</h5>
3305<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3306 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3307 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3308 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3309 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3310 &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]3311</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3312
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3313</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3314
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3315<!-- _______________________________________________________________________ -->
3316<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3317Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3318
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3319<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3320
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3321<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3322<pre>
3323 &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]3324</pre>
3325
3326<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3327<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3328 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3329
3330<h5>Arguments:</h5>
3331<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3332 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3333 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3334
3335<h5>Semantics:</h5>
3336<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3337 significant bits of the result will be filled with zero bits after the shift.
3338 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3339 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3340 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3341 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3342
3343<h5>Example:</h5>
3344<pre>
3345 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3346 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3347 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3348 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3349 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3350 &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]3351</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3352
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3353</div>
3354
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]3355<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3356<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3357Instruction</a> </div>
3358<div class="doc_text">
3359
3360<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3361<pre>
3362 &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]3363</pre>
3364
3365<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3366<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3367 operand shifted to the right a specified number of bits with sign
3368 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3369
3370<h5>Arguments:</h5>
3371<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3372 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3373 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3374
3375<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3376<p>This instruction always performs an arithmetic shift right operation, The
3377 most significant bits of the result will be filled with the sign bit
3378 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3379 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3380 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3381 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3382
3383<h5>Example:</h5>
3384<pre>
3385 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3386 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3387 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3388 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]3389 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]3390 &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]3391</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3392
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]3393</div>
3394
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3395<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3396<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3397Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3398
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3399<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3401<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3402<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]3403 &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]3404</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3405
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3406<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3407<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3408 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3409
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3410<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3411<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3412 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3413 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3414
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3415<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3416<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3418<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3419 <tbody>
3420 <tr>
3421 <td>In0</td>
3422 <td>In1</td>
3423 <td>Out</td>
3424 </tr>
3425 <tr>
3426 <td>0</td>
3427 <td>0</td>
3428 <td>0</td>
3429 </tr>
3430 <tr>
3431 <td>0</td>
3432 <td>1</td>
3433 <td>0</td>
3434 </tr>
3435 <tr>
3436 <td>1</td>
3437 <td>0</td>
3438 <td>0</td>
3439 </tr>
3440 <tr>
3441 <td>1</td>
3442 <td>1</td>
3443 <td>1</td>
3444 </tr>
3445 </tbody>
3446</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3447
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3448<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3449<pre>
3450 &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]3451 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3452 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3453</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3454</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3455<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3456<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3457
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3458<div class="doc_text">
3459
3460<h5>Syntax:</h5>
3461<pre>
3462 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3463</pre>
3464
3465<h5>Overview:</h5>
3466<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3467 two operands.</p>
3468
3469<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3470<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3471 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3472 values. Both arguments must have identical types.</p>
3473
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3474<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3475<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3476
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3477<table border="1" cellspacing="0" cellpadding="4">
3478 <tbody>
3479 <tr>
3480 <td>In0</td>
3481 <td>In1</td>
3482 <td>Out</td>
3483 </tr>
3484 <tr>
3485 <td>0</td>
3486 <td>0</td>
3487 <td>0</td>
3488 </tr>
3489 <tr>
3490 <td>0</td>
3491 <td>1</td>
3492 <td>1</td>
3493 </tr>
3494 <tr>
3495 <td>1</td>
3496 <td>0</td>
3497 <td>1</td>
3498 </tr>
3499 <tr>
3500 <td>1</td>
3501 <td>1</td>
3502 <td>1</td>
3503 </tr>
3504 </tbody>
3505</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3506
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3507<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3508<pre>
3509 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3510 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3511 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3512</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3513
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3514</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3515
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3516<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3517<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3518Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3519
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3520<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3521
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3522<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3523<pre>
3524 &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]3525</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3526
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3527<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3528<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3529 its two operands. The <tt>xor</tt> is used to implement the "one's
3530 complement" operation, which is the "~" operator in C.</p>
3531
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3532<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3533<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3534 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3535 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3536
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3537<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3538<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3539
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3540<table border="1" cellspacing="0" cellpadding="4">
3541 <tbody>
3542 <tr>
3543 <td>In0</td>
3544 <td>In1</td>
3545 <td>Out</td>
3546 </tr>
3547 <tr>
3548 <td>0</td>
3549 <td>0</td>
3550 <td>0</td>
3551 </tr>
3552 <tr>
3553 <td>0</td>
3554 <td>1</td>
3555 <td>1</td>
3556 </tr>
3557 <tr>
3558 <td>1</td>
3559 <td>0</td>
3560 <td>1</td>
3561 </tr>
3562 <tr>
3563 <td>1</td>
3564 <td>1</td>
3565 <td>0</td>
3566 </tr>
3567 </tbody>
3568</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3569
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3570<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3571<pre>
3572 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3573 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3574 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3575 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3576</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3577
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3578</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3579
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3580<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3581<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3582 <a name="vectorops">Vector Operations</a>
3583</div>
3584
3585<div class="doc_text">
3586
3587<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3588 target-independent manner. These instructions cover the element-access and
3589 vector-specific operations needed to process vectors effectively. While LLVM
3590 does directly support these vector operations, many sophisticated algorithms
3591 will want to use target-specific intrinsics to take full advantage of a
3592 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3593
3594</div>
3595
3596<!-- _______________________________________________________________________ -->
3597<div class="doc_subsubsection">
3598 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3599</div>
3600
3601<div class="doc_text">
3602
3603<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3604<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3605 &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]3606</pre>
3607
3608<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3609<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3610 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3611
3612
3613<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3614<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3615 of <a href="#t_vector">vector</a> type. The second operand is an index
3616 indicating the position from which to extract the element. The index may be
3617 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3618
3619<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3620<p>The result is a scalar of the same type as the element type of
3621 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3622 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3623 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3624
3625<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3626<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3627 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3628</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3629
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3630</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3631
3632<!-- _______________________________________________________________________ -->
3633<div class="doc_subsubsection">
3634 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3635</div>
3636
3637<div class="doc_text">
3638
3639<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3640<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]3641 &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]3642</pre>
3643
3644<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3645<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3646 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3647
3648<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3649<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3650 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3651 whose type must equal the element type of the first operand. The third
3652 operand is an index indicating the position at which to insert the value.
3653 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3654
3655<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3656<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3657 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3658 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3659 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3660
3661<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3662<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3663 %result = 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]3664</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3665
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3666</div>
3667
3668<!-- _______________________________________________________________________ -->
3669<div class="doc_subsubsection">
3670 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3671</div>
3672
3673<div class="doc_text">
3674
3675<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3676<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3677 &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]3678</pre>
3679
3680<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3681<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3682 from two input vectors, returning a vector with the same element type as the
3683 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3684
3685<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3686<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3687 with types that match each other. The third argument is a shuffle mask whose
3688 element type is always 'i32'. The result of the instruction is a vector
3689 whose length is the same as the shuffle mask and whose element type is the
3690 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3691
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3692<p>The shuffle mask operand is required to be a constant vector with either
3693 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3694
3695<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3696<p>The elements of the two input vectors are numbered from left to right across
3697 both of the vectors. The shuffle mask operand specifies, for each element of
3698 the result vector, which element of the two input vectors the result element
3699 gets. The element selector may be undef (meaning "don't care") and the
3700 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3701
3702<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3703<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3704 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3705 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3706 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3707 &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.
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]3708 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3709 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3710 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3711 &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]3712</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3713
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3714</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]3715
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]3716<!-- ======================================================================= -->
3717<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3718 <a name="aggregateops">Aggregate Operations</a>
3719</div>
3720
3721<div class="doc_text">
3722
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3724
3725</div>
3726
3727<!-- _______________________________________________________________________ -->
3728<div class="doc_subsubsection">
3729 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3730</div>
3731
3732<div class="doc_text">
3733
3734<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3735<pre>
3736 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3737</pre>
3738
3739<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3740<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3741 or array element from an aggregate value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3742
3743<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3744<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3745 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3746 operands are constant indices to specify which value to extract in a similar
3747 manner as indices in a
3748 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3749
3750<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3751<p>The result is the value at the position in the aggregate specified by the
3752 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3753
3754<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3755<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]3756 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3757</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3758
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3759</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3760
3761<!-- _______________________________________________________________________ -->
3762<div class="doc_subsubsection">
3763 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3764</div>
3765
3766<div class="doc_text">
3767
3768<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3769<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +0000[diff] [blame]3770 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3771</pre>
3772
3773<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3774<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3775 array element in an aggregate.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3776
3777
3778<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3779<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3780 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3781 second operand is a first-class value to insert. The following operands are
3782 constant indices indicating the position at which to insert the value in a
3783 similar manner as indices in a
3784 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3785 value to insert must have the same type as the value identified by the
3786 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3787
3788<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3790 that of <tt>val</tt> except that the value at the position specified by the
3791 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3792
3793<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3794<pre>
Dan Gohman88ce1a52008-06-23 15:26:37 +0000[diff] [blame]3795 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3796</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3797
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]3798</div>
3799
3800
3801<!-- ======================================================================= -->
3802<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3803 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3804</div>
3805
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3806<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3807
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3808<p>A key design point of an SSA-based representation is how it represents
3809 memory. In LLVM, no memory locations are in SSA form, which makes things
3810 very simple. This section describes how to read, write, allocate, and free
3811 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3812
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3813</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3814
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3815<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3816<div class="doc_subsubsection">
3817 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3818</div>
3819
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3820<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3822<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3823<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3824 &lt;result&gt; = malloc &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]3825</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3826
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3827<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3829 returns a pointer to it. The object is always allocated in the generic
3830 address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3831
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3832<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3833<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3834 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3835 system and returns a pointer of the appropriate type to the program. If
3836 "NumElements" is specified, it is the number of elements allocated, otherwise
3837 "NumElements" is defaulted to be one. If a constant alignment is specified,
3838 the value result of the allocation is guaranteed to be aligned to at least
3839 that boundary. If not specified, or if zero, the target can choose to align
3840 the allocation on any convenient boundary compatible with the type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3841
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3842<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3843
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3844<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3845<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3846 pointer is returned. The result of a zero byte allocation is undefined. The
3847 result is null if there is insufficient memory available.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3848
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3849<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3850<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3851 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3852
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3853 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3854 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3855 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3856 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3857 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3858</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3859
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3860<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3861
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3862</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3863
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3864<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3865<div class="doc_subsubsection">
3866 <a name="i_free">'<tt>free</tt>' Instruction</a>
3867</div>
3868
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3869<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3870
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3871<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3872<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3873 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3874</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3875
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3876<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3877<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3878 to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3879
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3880<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3881<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3882 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3884<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3885<p>Access to the memory pointed to by the pointer is no longer defined after
3886 this instruction executes. If the pointer is null, the operation is a
3887 noop.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3888
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3889<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3890<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3891 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3892 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3893</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3894
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3895</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3896
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3897<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3898<div class="doc_subsubsection">
3899 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3900</div>
3901
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3902<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3903
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3904<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3905<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3906 &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]3907</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3909<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3910<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3911 currently executing function, to be automatically released when this function
3912 returns to its caller. The object is always allocated in the generic address
3913 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3914
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3915<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916<p>The '<tt>alloca</tt>' instruction
3917 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3918 runtime stack, returning a pointer of the appropriate type to the program.
3919 If "NumElements" is specified, it is the number of elements allocated,
3920 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3921 specified, the value result of the allocation is guaranteed to be aligned to
3922 at least that boundary. If not specified, or if zero, the target can choose
3923 to align the allocation on any convenient boundary compatible with the
3924 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3925
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3926<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3927
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3928<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]3929<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3930 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3931 memory is automatically released when the function returns. The
3932 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3933 variables that must have an address available. When the function returns
3934 (either with the <tt><a href="#i_ret">ret</a></tt>
3935 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3936 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3937
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3938<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3939<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]3940 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3942 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3943 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3944</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3945
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3946</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3947
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3948<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3949<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3950Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3951
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3952<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3953
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3954<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3955<pre>
3956 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3957 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3958</pre>
3959
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3960<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3961<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3962
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3963<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3964<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3965 from which to load. The pointer must point to
3966 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3967 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3968 number or order of execution of this <tt>load</tt> with other
3969 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3970 instructions. </p>
3971
3972<p>The optional constant "align" argument specifies the alignment of the
3973 operation (that is, the alignment of the memory address). A value of 0 or an
3974 omitted "align" argument means that the operation has the preferential
3975 alignment for the target. It is the responsibility of the code emitter to
3976 ensure that the alignment information is correct. Overestimating the
3977 alignment results in an undefined behavior. Underestimating the alignment may
3978 produce less efficient code. An alignment of 1 is always safe.</p>
3979
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3980<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981<p>The location of memory pointed to is loaded. If the value being loaded is of
3982 scalar type then the number of bytes read does not exceed the minimum number
3983 of bytes needed to hold all bits of the type. For example, loading an
3984 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3985 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3986 is undefined if the value was not originally written using a store of the
3987 same type.</p>
3988
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3989<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3990<pre>
3991 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3992 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3993 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3994</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3995
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3996</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3997
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3998<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3999<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4000Instruction</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4001
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]4002<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4003
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4004<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4005<pre>
4006 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]4007 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4008</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4009
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4010<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4011<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4012
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4013<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4014<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4015 and an address at which to store it. The type of the
4016 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4017 the <a href="#t_firstclass">first class</a> type of the
4018 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4019 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4020 or order of execution of this <tt>store</tt> with other
4021 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4022 instructions.</p>
4023
4024<p>The optional constant "align" argument specifies the alignment of the
4025 operation (that is, the alignment of the memory address). A value of 0 or an
4026 omitted "align" argument means that the operation has the preferential
4027 alignment for the target. It is the responsibility of the code emitter to
4028 ensure that the alignment information is correct. Overestimating the
4029 alignment results in an undefined behavior. Underestimating the alignment may
4030 produce less efficient code. An alignment of 1 is always safe.</p>
4031
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4032<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4033<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4034 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4035 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4036 does not exceed the minimum number of bytes needed to hold all bits of the
4037 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4038 writing a value of a type like <tt>i20</tt> with a size that is not an
4039 integral number of bytes, it is unspecified what happens to the extra bits
4040 that do not belong to the type, but they will typically be overwritten.</p>
4041
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4042<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4043<pre>
4044 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4045 store i32 3, i32* %ptr <i>; yields {void}</i>
4046 %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]4047</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4048
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4049</div>
4050
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4051<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4052<div class="doc_subsubsection">
4053 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4054</div>
4055
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4056<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4057
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4058<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4059<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4060 &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]4061 &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]4062</pre>
4063
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4064<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4065<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4066 subelement of an aggregate data structure. It performs address calculation
4067 only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4068
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4069<h5>Arguments:</h5>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4070<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4071 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4072 elements of the aggregate object are indexed. The interpretation of each
4073 index is dependent on the type being indexed into. The first index always
4074 indexes the pointer value given as the first argument, the second index
4075 indexes a value of the type pointed to (not necessarily the value directly
4076 pointed to, since the first index can be non-zero), etc. The first type
4077 indexed into must be a pointer value, subsequent types can be arrays, vectors
4078 and structs. Note that subsequent types being indexed into can never be
4079 pointers, since that would require loading the pointer before continuing
4080 calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4081
4082<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4083 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4084 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]4085 vector, integers of any width are allowed, and they are not required to be
4086 constant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4087
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4088<p>For example, let's consider a C code fragment and how it gets compiled to
4089 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4090
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4091<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4092<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4093struct RT {
4094 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4095 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4096 char C;
4097};
4098struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4099 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4100 double Y;
4101 struct RT Z;
4102};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4103
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]4104int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4105 return &amp;s[1].Z.B[5][13];
4106}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4107</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4108</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4109
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4110<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4111
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4112<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4113<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]4114%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4115%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4116
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4117define i32* @foo(%ST* %s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4118entry:
4119 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4120 ret i32* %reg
4121}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4122</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4123</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4124
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4125<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4126<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]4127 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4128 }</tt>' type, a structure. The second index indexes into the third element
4129 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4130 i8 }</tt>' type, another structure. The third index indexes into the second
4131 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4132 array. The two dimensions of the array are subscripted into, yielding an
4133 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4134 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4135
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4136<p>Note that it is perfectly legal to index partially through a structure,
4137 returning a pointer to an inner element. Because of this, the LLVM code for
4138 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4139
4140<pre>
Dan Gohman6b867702009-07-25 02:23:48 +0000[diff] [blame]4141 define i32* @foo(%ST* %s) {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4142 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4143 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4144 %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]4145 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4146 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4147 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4148 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4149</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]4150
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4151<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4152 <tt>getelementptr</tt> is undefined if the base pointer is not an
4153 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4154 that would be formed by successive addition of the offsets implied by the
4155 indices to the base address with infinitely precise arithmetic are not an
4156 <i>in bounds</i> address of that allocated object.
Dan Gohman61acaaa2009-07-29 16:00:30 +0000[diff] [blame]4157 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman2de532c2009-08-20 17:08:17 +0000[diff] [blame]4158 that point into the object, plus the address one byte past the end.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]4159
4160<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4161 the base address with silently-wrapping two's complement arithmetic, and
4162 the result value of the <tt>getelementptr</tt> may be outside the object
4163 pointed to by the base pointer. The result value may not necessarily be
4164 used to access memory though, even if it happens to point into allocated
4165 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4166 section for more information.</p>
4167
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4168<p>The getelementptr instruction is often confusing. For some more insight into
4169 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4170
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]4171<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4172<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4173 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]4174 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4175 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4176 %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]4177 <i>; yields i8*:eptr</i>
4178 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]4179 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]4180 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4181</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4182
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]4183</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4184
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4185<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4186<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4187</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4189<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4190
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4191<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4192 which all take a single operand and a type. They perform various bit
4193 conversions on the operand.</p>
4194
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4195</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4196
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4197<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4198<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4199 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4200</div>
4201<div class="doc_text">
4202
4203<h5>Syntax:</h5>
4204<pre>
4205 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4206</pre>
4207
4208<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4209<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4210 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4211
4212<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4213<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4214 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4215 size and type of the result, which must be
4216 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4217 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4218 allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4219
4220<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4221<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4222 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4223 source size must be larger than the destination size, <tt>trunc</tt> cannot
4224 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4225
4226<h5>Example:</h5>
4227<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4228 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4229 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4230 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4231</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4232
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4233</div>
4234
4235<!-- _______________________________________________________________________ -->
4236<div class="doc_subsubsection">
4237 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4238</div>
4239<div class="doc_text">
4240
4241<h5>Syntax:</h5>
4242<pre>
4243 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4244</pre>
4245
4246<h5>Overview:</h5>
4247<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4248 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4249
4250
4251<h5>Arguments:</h5>
4252<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]4253 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4254 also be of <a href="#t_integer">integer</a> type. The bit size of the
4255 <tt>value</tt> must be smaller than the bit size of the destination type,
4256 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4257
4258<h5>Semantics:</h5>
4259<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]4260 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4261
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]4262<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]4263
4264<h5>Example:</h5>
4265<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4266 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4267 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4268</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4269
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4270</div>
4271
4272<!-- _______________________________________________________________________ -->
4273<div class="doc_subsubsection">
4274 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4275</div>
4276<div class="doc_text">
4277
4278<h5>Syntax:</h5>
4279<pre>
4280 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4281</pre>
4282
4283<h5>Overview:</h5>
4284<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4285
4286<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4287<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4288 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4289 also be of <a href="#t_integer">integer</a> type. The bit size of the
4290 <tt>value</tt> must be smaller than the bit size of the destination type,
4291 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4292
4293<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4295 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4296 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4297
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4298<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]4299
4300<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4301<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4302 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4303 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4304</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4305
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4306</div>
4307
4308<!-- _______________________________________________________________________ -->
4309<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4310 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4311</div>
4312
4313<div class="doc_text">
4314
4315<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4316<pre>
4317 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4318</pre>
4319
4320<h5>Overview:</h5>
4321<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4322 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4323
4324<h5>Arguments:</h5>
4325<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4326 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4327 to cast it to. The size of <tt>value</tt> must be larger than the size of
4328 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4329 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4330
4331<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4332<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4333 <a href="#t_floating">floating point</a> type to a smaller
4334 <a href="#t_floating">floating point</a> type. If the value cannot fit
4335 within the destination type, <tt>ty2</tt>, then the results are
4336 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4337
4338<h5>Example:</h5>
4339<pre>
4340 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4341 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4342</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4343
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]4344</div>
4345
4346<!-- _______________________________________________________________________ -->
4347<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4348 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4349</div>
4350<div class="doc_text">
4351
4352<h5>Syntax:</h5>
4353<pre>
4354 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4355</pre>
4356
4357<h5>Overview:</h5>
4358<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]4359 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4360
4361<h5>Arguments:</h5>
4362<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4363 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4364 a <a href="#t_floating">floating point</a> type to cast it to. The source
4365 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4366
4367<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4368<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4369 <a href="#t_floating">floating point</a> type to a larger
4370 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4371 used to make a <i>no-op cast</i> because it always changes bits. Use
4372 <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]4373
4374<h5>Example:</h5>
4375<pre>
4376 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4377 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4378</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4379
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4380</div>
4381
4382<!-- _______________________________________________________________________ -->
4383<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]4384 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4385</div>
4386<div class="doc_text">
4387
4388<h5>Syntax:</h5>
4389<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4390 &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]4391</pre>
4392
4393<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4394<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4395 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4396
4397<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4398<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4399 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4400 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4401 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4402 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4403
4404<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4405<p>The '<tt>fptoui</tt>' instruction converts its
4406 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4407 towards zero) unsigned integer value. If the value cannot fit
4408 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4409
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4410<h5>Example:</h5>
4411<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4412 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4413 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]4414 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4415</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4416
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4417</div>
4418
4419<!-- _______________________________________________________________________ -->
4420<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4421 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4422</div>
4423<div class="doc_text">
4424
4425<h5>Syntax:</h5>
4426<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4427 &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]4428</pre>
4429
4430<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4431<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4432 <a href="#t_floating">floating point</a> <tt>value</tt> to
4433 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4434
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4435<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4437 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4438 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4439 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4440 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4441
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4442<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4443<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4444 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4445 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4446 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4447
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]4448<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4449<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4450 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]4451 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4452 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4453</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4454
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4455</div>
4456
4457<!-- _______________________________________________________________________ -->
4458<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4459 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4460</div>
4461<div class="doc_text">
4462
4463<h5>Syntax:</h5>
4464<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4465 &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]4466</pre>
4467
4468<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4469<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4470 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4471
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4472<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4473<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]4474 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4475 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4476 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4477 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4478
4479<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4480<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4481 integer quantity and converts it to the corresponding floating point
4482 value. If the value cannot fit in the floating point value, the results are
4483 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4484
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4485<h5>Example:</h5>
4486<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4487 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4488 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4489</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4490
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4491</div>
4492
4493<!-- _______________________________________________________________________ -->
4494<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4495 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4496</div>
4497<div class="doc_text">
4498
4499<h5>Syntax:</h5>
4500<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]4501 &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]4502</pre>
4503
4504<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4505<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4506 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4507
4508<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]4509<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]4510 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4511 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4512 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4513 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4514
4515<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4516<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4517 quantity and converts it to the corresponding floating point value. If the
4518 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4519
4520<h5>Example:</h5>
4521<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4522 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4523 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4524</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4525
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4526</div>
4527
4528<!-- _______________________________________________________________________ -->
4529<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4530 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4531</div>
4532<div class="doc_text">
4533
4534<h5>Syntax:</h5>
4535<pre>
4536 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4537</pre>
4538
4539<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4540<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4541 the integer type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4542
4543<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4544<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4545 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4546 <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]4547
4548<h5>Semantics:</h5>
4549<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4550 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4551 truncating or zero extending that value to the size of the integer type. If
4552 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4553 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4554 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4555 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4556
4557<h5>Example:</h5>
4558<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4559 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4560 %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]4561</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4562
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4563</div>
4564
4565<!-- _______________________________________________________________________ -->
4566<div class="doc_subsubsection">
4567 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4568</div>
4569<div class="doc_text">
4570
4571<h5>Syntax:</h5>
4572<pre>
4573 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4574</pre>
4575
4576<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4577<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4578 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4579
4580<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4581<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4582 value to cast, and a type to cast it to, which must be a
4583 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4584
4585<h5>Semantics:</h5>
4586<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4587 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4588 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4589 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4590 than the size of a pointer then a zero extension is done. If they are the
4591 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4592
4593<h5>Example:</h5>
4594<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4595 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4596 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4597 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4598</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4599
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]4600</div>
4601
4602<!-- _______________________________________________________________________ -->
4603<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4604 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4605</div>
4606<div class="doc_text">
4607
4608<h5>Syntax:</h5>
4609<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4610 &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]4611</pre>
4612
4613<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4614<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4615 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4616
4617<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4618<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4619 non-aggregate first class value, and a type to cast it to, which must also be
4620 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4621 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4622 identical. If the source type is a pointer, the destination type must also be
4623 a pointer. This instruction supports bitwise conversion of vectors to
4624 integers and to vectors of other types (as long as they have the same
4625 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4626
4627<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]4628<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4629 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4630 this conversion. The conversion is done as if the <tt>value</tt> had been
4631 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4632 be converted to other pointer types with this instruction. To convert
4633 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4634 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]4635
4636<h5>Example:</h5>
4637<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4638 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4639 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4640 %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]4641</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4643</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4644
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4645<!-- ======================================================================= -->
4646<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4647
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4648<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4649
4650<p>The instructions in this category are the "miscellaneous" instructions, which
4651 defy better classification.</p>
4652
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4653</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4657</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4658
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4659<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4660
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4661<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4662<pre>
4663 &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]4664</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4665
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4666<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4667<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4668 boolean values based on comparison of its two integer, integer vector, or
4669 pointer operands.</p>
4670
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4671<h5>Arguments:</h5>
4672<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4673 the condition code indicating the kind of comparison to perform. It is not a
4674 value, just a keyword. The possible condition code are:</p>
4675
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4676<ol>
4677 <li><tt>eq</tt>: equal</li>
4678 <li><tt>ne</tt>: not equal </li>
4679 <li><tt>ugt</tt>: unsigned greater than</li>
4680 <li><tt>uge</tt>: unsigned greater or equal</li>
4681 <li><tt>ult</tt>: unsigned less than</li>
4682 <li><tt>ule</tt>: unsigned less or equal</li>
4683 <li><tt>sgt</tt>: signed greater than</li>
4684 <li><tt>sge</tt>: signed greater or equal</li>
4685 <li><tt>slt</tt>: signed less than</li>
4686 <li><tt>sle</tt>: signed less or equal</li>
4687</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4688
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]4689<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4690 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4691 typed. They must also be identical types.</p>
4692
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4693<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4694<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4695 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4696 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]4697 result, as follows:</p>
4698
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4699<ol>
4700 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4701 <tt>false</tt> otherwise. No sign interpretation is necessary or
4702 performed.</li>
4703
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4704 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4705 <tt>false</tt> otherwise. No sign interpretation is necessary or
4706 performed.</li>
4707
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4708 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4709 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4710
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4711 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4712 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4713 to <tt>op2</tt>.</li>
4714
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4715 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4716 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4717
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4718 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4719 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4720
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4721 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4722 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4723
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4724 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4725 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4726 to <tt>op2</tt>.</li>
4727
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4728 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4729 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4730
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4731 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4732 <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]4733</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4734
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4735<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4736 values are compared as if they were integers.</p>
4737
4738<p>If the operands are integer vectors, then they are compared element by
4739 element. The result is an <tt>i1</tt> vector with the same number of elements
4740 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4741
4742<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4743<pre>
4744 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4745 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4746 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4747 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4748 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4749 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4750</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4751
4752<p>Note that the code generator does not yet support vector types with
4753 the <tt>icmp</tt> instruction.</p>
4754
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4755</div>
4756
4757<!-- _______________________________________________________________________ -->
4758<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4759</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4760
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4761<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4762
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4763<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4764<pre>
4765 &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]4766</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4767
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4768<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4769<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4770 values based on comparison of its operands.</p>
4771
4772<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]4773(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4774
4775<p>If the operands are floating point vectors, then the result type is a vector
4776 of boolean with the same number of elements as the operands being
4777 compared.</p>
4778
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4779<h5>Arguments:</h5>
4780<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4781 the condition code indicating the kind of comparison to perform. It is not a
4782 value, just a keyword. The possible condition code are:</p>
4783
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4784<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4785 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4786 <li><tt>oeq</tt>: ordered and equal</li>
4787 <li><tt>ogt</tt>: ordered and greater than </li>
4788 <li><tt>oge</tt>: ordered and greater than or equal</li>
4789 <li><tt>olt</tt>: ordered and less than </li>
4790 <li><tt>ole</tt>: ordered and less than or equal</li>
4791 <li><tt>one</tt>: ordered and not equal</li>
4792 <li><tt>ord</tt>: ordered (no nans)</li>
4793 <li><tt>ueq</tt>: unordered or equal</li>
4794 <li><tt>ugt</tt>: unordered or greater than </li>
4795 <li><tt>uge</tt>: unordered or greater than or equal</li>
4796 <li><tt>ult</tt>: unordered or less than </li>
4797 <li><tt>ule</tt>: unordered or less than or equal</li>
4798 <li><tt>une</tt>: unordered or not equal</li>
4799 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4800 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4801</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4802
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4803<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4804 <i>unordered</i> means that either operand may be a QNAN.</p>
4805
4806<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4807 a <a href="#t_floating">floating point</a> type or
4808 a <a href="#t_vector">vector</a> of floating point type. They must have
4809 identical types.</p>
4810
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4811<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4812<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4813 according to the condition code given as <tt>cond</tt>. If the operands are
4814 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]4815 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4816 follows:</p>
4817
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4818<ol>
4819 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4820
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4821 <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]4822 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4823
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4824 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4825 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4826
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4827 <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]4828 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4829
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4830 <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]4831 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4832
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4833 <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]4834 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4835
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4836 <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]4837 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4838
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4839 <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]4840
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4841 <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]4842 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4843
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4844 <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]4845 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4846
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4847 <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]4848 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4849
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4852
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4855
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4856 <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]4857 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4858
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]4859 <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]4860
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4861 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4862</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4863
4864<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4865<pre>
4866 &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]4867 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4868 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4869 &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]4870</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4871
4872<p>Note that the code generator does not yet support vector types with
4873 the <tt>fcmp</tt> instruction.</p>
4874
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]4875</div>
4876
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4877<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]4878<div class="doc_subsubsection">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4879 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4880</div>
4881
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4882<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4883
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4884<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4885<pre>
4886 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4887</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4888
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4889<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4890<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4891 SSA graph representing the function.</p>
4892
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4893<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4894<p>The type of the incoming values is specified with the first type field. After
4895 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4896 one pair for each predecessor basic block of the current block. Only values
4897 of <a href="#t_firstclass">first class</a> type may be used as the value
4898 arguments to the PHI node. Only labels may be used as the label
4899 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4900
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4901<p>There must be no non-phi instructions between the start of a basic block and
4902 the PHI instructions: i.e. PHI instructions must be first in a basic
4903 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4904
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4905<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4906 occur on the edge from the corresponding predecessor block to the current
4907 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4908 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]4909
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4910<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4911<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4912 specified by the pair corresponding to the predecessor basic block that
4913 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4914
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4915<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4916<pre>
4917Loop: ; Infinite loop that counts from 0 on up...
4918 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4919 %nextindvar = add i32 %indvar, 1
4920 br label %Loop
4921</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4922
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4923</div>
4924
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4925<!-- _______________________________________________________________________ -->
4926<div class="doc_subsubsection">
4927 <a name="i_select">'<tt>select</tt>' Instruction</a>
4928</div>
4929
4930<div class="doc_text">
4931
4932<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4933<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]4934 &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>
4935
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]4936 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4937</pre>
4938
4939<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4940<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4941 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4942
4943
4944<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4945<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4946 values indicating the condition, and two values of the
4947 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4948 vectors and the condition is a scalar, then entire vectors are selected, not
4949 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4950
4951<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4952<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4953 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4954
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4955<p>If the condition is a vector of i1, then the value arguments must be vectors
4956 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4957
4958<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4959<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4960 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4961</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]4962
4963<p>Note that the code generator does not yet support conditions
4964 with vector type.</p>
4965
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4966</div>
4967
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]4968<!-- _______________________________________________________________________ -->
4969<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4970 <a name="i_call">'<tt>call</tt>' Instruction</a>
4971</div>
4972
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4973<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4974
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4975<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4976<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]4977 &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]4978</pre>
4979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4980<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4981<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4982
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4983<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4984<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4985
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4986<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4987 <li>The optional "tail" marker indicates whether the callee function accesses
4988 any allocas or varargs in the caller. If the "tail" marker is present,
4989 the function call is eligible for tail call optimization. Note that calls
4990 may be marked "tail" even if they do not occur before
4991 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]4992
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4993 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4994 convention</a> the call should use. If none is specified, the call
4995 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]4996
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4997 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4998 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4999 '<tt>inreg</tt>' attributes are valid here.</li>
5000
5001 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5002 type of the return value. Functions that return no value are marked
5003 <tt><a href="#t_void">void</a></tt>.</li>
5004
5005 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5006 being invoked. The argument types must match the types implied by this
5007 signature. This type can be omitted if the function is not varargs and if
5008 the function type does not return a pointer to a function.</li>
5009
5010 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5011 be invoked. In most cases, this is a direct function invocation, but
5012 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5013 to function value.</li>
5014
5015 <li>'<tt>function args</tt>': argument list whose types match the function
5016 signature argument types. All arguments must be of
5017 <a href="#t_firstclass">first class</a> type. If the function signature
5018 indicates the function accepts a variable number of arguments, the extra
5019 arguments can be specified.</li>
5020
5021 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5022 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5023 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5024</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5025
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5026<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5027<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5028 a specified function, with its incoming arguments bound to the specified
5029 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5030 function, control flow continues with the instruction after the function
5031 call, and the return value of the function is bound to the result
5032 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5033
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5034<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5035<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]5036 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]5037 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5038 %X = tail call i32 @foo() <i>; yields i32</i>
5039 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5040 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]5041
5042 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]5043 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]5044 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5045 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]5046 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]5047 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]5048</pre>
5049
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5050<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]5051standard C99 library as being the C99 library functions, and may perform
5052optimizations or generate code for them under that assumption. This is
5053something we'd like to change in the future to provide better support for
5054freestanding environments and non-C-based langauges.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]5055
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5056</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5057
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5058<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5059<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]5060 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5061</div>
5062
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5063<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5064
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5065<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5066<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5067 &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]5068</pre>
5069
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5070<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5071<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5072 the "variable argument" area of a function call. It is used to implement the
5073 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5074
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5075<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5076<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5077 argument. It returns a value of the specified argument type and increments
5078 the <tt>va_list</tt> to point to the next argument. The actual type
5079 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5080
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5081<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5082<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5083 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5084 to the next argument. For more information, see the variable argument
5085 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5086
5087<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]5088 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5089 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5090
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5091<p><tt>va_arg</tt> is an LLVM instruction instead of
5092 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5093 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5094
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]5095<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]5096<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5097
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5098<p>Note that the code generator does not yet fully support va_arg on many
5099 targets. Also, it does not currently support va_arg with aggregate types on
5100 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]5101
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5102</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5103
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5104<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]5105<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5106<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5107
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5108<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5109
5110<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5111 well known names and semantics and are required to follow certain
5112 restrictions. Overall, these intrinsics represent an extension mechanism for
5113 the LLVM language that does not require changing all of the transformations
5114 in LLVM when adding to the language (or the bitcode reader/writer, the
5115 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5116
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]5117<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5118 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5119 begin with this prefix. Intrinsic functions must always be external
5120 functions: you cannot define the body of intrinsic functions. Intrinsic
5121 functions may only be used in call or invoke instructions: it is illegal to
5122 take the address of an intrinsic function. Additionally, because intrinsic
5123 functions are part of the LLVM language, it is required if any are added that
5124 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5125
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5126<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5127 family of functions that perform the same operation but on different data
5128 types. Because LLVM can represent over 8 million different integer types,
5129 overloading is used commonly to allow an intrinsic function to operate on any
5130 integer type. One or more of the argument types or the result type can be
5131 overloaded to accept any integer type. Argument types may also be defined as
5132 exactly matching a previous argument's type or the result type. This allows
5133 an intrinsic function which accepts multiple arguments, but needs all of them
5134 to be of the same type, to only be overloaded with respect to a single
5135 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5136
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5137<p>Overloaded intrinsics will have the names of its overloaded argument types
5138 encoded into its function name, each preceded by a period. Only those types
5139 which are overloaded result in a name suffix. Arguments whose type is matched
5140 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5141 can take an integer of any width and returns an integer of exactly the same
5142 integer width. This leads to a family of functions such as
5143 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5144 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5145 suffix is required. Because the argument's type is matched against the return
5146 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5147
5148<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5149 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5150
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5151</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5152
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5153<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5154<div class="doc_subsection">
5155 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5156</div>
5157
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5158<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5159
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5160<p>Variable argument support is defined in LLVM with
5161 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5162 intrinsic functions. These functions are related to the similarly named
5163 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5164
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5165<p>All of these functions operate on arguments that use a target-specific value
5166 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5167 not define what this type is, so all transformations should be prepared to
5168 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5169
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]5170<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]5171 instruction and the variable argument handling intrinsic functions are
5172 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5173
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5174<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5175<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5176define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5177 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5178 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5179 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5180 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5181
5182 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5183 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5184
5185 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5186 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5187 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5188 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5189 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5190
5191 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5192 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5193 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5194}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]5195
5196declare void @llvm.va_start(i8*)
5197declare void @llvm.va_copy(i8*, i8*)
5198declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5199</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5200</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5201
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5202</div>
5203
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5204<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5205<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5206 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5207</div>
5208
5209
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5210<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5211
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5212<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5213<pre>
5214 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5215</pre>
5216
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5217<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5218<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5219 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]5220
5221<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5222<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]5223
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5224<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5225<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]5226 macro available in C. In a target-dependent way, it initializes
5227 the <tt>va_list</tt> element to which the argument points, so that the next
5228 call to <tt>va_arg</tt> will produce the first variable argument passed to
5229 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5230 need to know the last argument of the function as the compiler can figure
5231 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5232
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5233</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5234
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5235<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5236<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5237 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5238</div>
5239
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5240<div class="doc_text">
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5241
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5242<h5>Syntax:</h5>
5243<pre>
5244 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5245</pre>
5246
5247<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5248<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249 which has been initialized previously
5250 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5251 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5252
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5253<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5254<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]5255
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5256<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5257<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]5258 macro available in C. In a target-dependent way, it destroys
5259 the <tt>va_list</tt> element to which the argument points. Calls
5260 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5261 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5262 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]5263
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5264</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5265
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5266<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5267<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5268 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5269</div>
5270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5271<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5272
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5273<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5274<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5275 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5276</pre>
5277
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5278<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5279<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5280 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5281
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5282<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]5283<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]5284 The second argument is a pointer to a <tt>va_list</tt> element to copy
5285 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5286
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]5287<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5288<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]5289 macro available in C. In a target-dependent way, it copies the
5290 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5291 element. This intrinsic is necessary because
5292 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5293 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5294
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5295</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5296
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5297<!-- ======================================================================= -->
5298<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5299 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5300</div>
5301
5302<div class="doc_text">
5303
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5304<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]5305Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5306intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5307roots on the stack</a>, as well as garbage collector implementations that
5308require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5309barriers. Front-ends for type-safe garbage collected languages should generate
5310these intrinsics to make use of the LLVM garbage collectors. For more details,
5311see <a href="GarbageCollection.html">Accurate Garbage Collection with
5312LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5313
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5314<p>The garbage collection intrinsics only operate on objects in the generic
5315 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]5316
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5317</div>
5318
5319<!-- _______________________________________________________________________ -->
5320<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5321 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5322</div>
5323
5324<div class="doc_text">
5325
5326<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5327<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5328 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5329</pre>
5330
5331<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]5332<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]5333 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5334
5335<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5336<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5337 root pointer. The second pointer (which must be either a constant or a
5338 global value address) contains the meta-data to be associated with the
5339 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5340
5341<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]5342<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]5343 location. At compile-time, the code generator generates information to allow
5344 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5345 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5346 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5347
5348</div>
5349
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5350<!-- _______________________________________________________________________ -->
5351<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5352 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5353</div>
5354
5355<div class="doc_text">
5356
5357<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5358<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5359 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5360</pre>
5361
5362<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5363<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5364 locations, allowing garbage collector implementations that require read
5365 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5366
5367<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5368<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]5369 allocated from the garbage collector. The first object is a pointer to the
5370 start of the referenced object, if needed by the language runtime (otherwise
5371 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5372
5373<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5374<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5375 instruction, but may be replaced with substantially more complex code by the
5376 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5377 may only be used in a function which <a href="#gc">specifies a GC
5378 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5379
5380</div>
5381
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5382<!-- _______________________________________________________________________ -->
5383<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5384 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5385</div>
5386
5387<div class="doc_text">
5388
5389<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5390<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5391 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5392</pre>
5393
5394<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5395<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5396 locations, allowing garbage collector implementations that require write
5397 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5398
5399<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]5400<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]5401 object to store it to, and the third is the address of the field of Obj to
5402 store to. If the runtime does not require a pointer to the object, Obj may
5403 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5404
5405<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5406<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5407 instruction, but may be replaced with substantially more complex code by the
5408 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5409 may only be used in a function which <a href="#gc">specifies a GC
5410 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5411
5412</div>
5413
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]5414<!-- ======================================================================= -->
5415<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5416 <a name="int_codegen">Code Generator Intrinsics</a>
5417</div>
5418
5419<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5420
5421<p>These intrinsics are provided by LLVM to expose special features that may
5422 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5423
5424</div>
5425
5426<!-- _______________________________________________________________________ -->
5427<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5428 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5429</div>
5430
5431<div class="doc_text">
5432
5433<h5>Syntax:</h5>
5434<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5435 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5436</pre>
5437
5438<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5439<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5440 target-specific value indicating the return address of the current function
5441 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5442
5443<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5444<p>The argument to this intrinsic indicates which function to return the address
5445 for. Zero indicates the calling function, one indicates its caller, etc.
5446 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5447
5448<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5449<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5450 indicating the return address of the specified call frame, or zero if it
5451 cannot be identified. The value returned by this intrinsic is likely to be
5452 incorrect or 0 for arguments other than zero, so it should only be used for
5453 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5454
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5455<p>Note that calling this intrinsic does not prevent function inlining or other
5456 aggressive transformations, so the value returned may not be that of the
5457 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5458
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5459</div>
5460
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5461<!-- _______________________________________________________________________ -->
5462<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5463 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5464</div>
5465
5466<div class="doc_text">
5467
5468<h5>Syntax:</h5>
5469<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5470 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5471</pre>
5472
5473<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5474<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5475 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5476
5477<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5478<p>The argument to this intrinsic indicates which function to return the frame
5479 pointer for. Zero indicates the calling function, one indicates its caller,
5480 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5481
5482<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5483<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5484 indicating the frame address of the specified call frame, or zero if it
5485 cannot be identified. The value returned by this intrinsic is likely to be
5486 incorrect or 0 for arguments other than zero, so it should only be used for
5487 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5488
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5489<p>Note that calling this intrinsic does not prevent function inlining or other
5490 aggressive transformations, so the value returned may not be that of the
5491 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5492
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5493</div>
5494
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5495<!-- _______________________________________________________________________ -->
5496<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5497 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5498</div>
5499
5500<div class="doc_text">
5501
5502<h5>Syntax:</h5>
5503<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5504 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5505</pre>
5506
5507<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5508<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5509 of the function stack, for use
5510 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5511 useful for implementing language features like scoped automatic variable
5512 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5513
5514<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5515<p>This intrinsic returns a opaque pointer value that can be passed
5516 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5517 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5518 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5519 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5520 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5521 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5522
5523</div>
5524
5525<!-- _______________________________________________________________________ -->
5526<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5527 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5528</div>
5529
5530<div class="doc_text">
5531
5532<h5>Syntax:</h5>
5533<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5534 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5535</pre>
5536
5537<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5538<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5539 the function stack to the state it was in when the
5540 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5541 executed. This is useful for implementing language features like scoped
5542 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5543
5544<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5545<p>See the description
5546 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5547
5548</div>
5549
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]5550<!-- _______________________________________________________________________ -->
5551<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5552 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5553</div>
5554
5555<div class="doc_text">
5556
5557<h5>Syntax:</h5>
5558<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5559 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]5560</pre>
5561
5562<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5563<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5564 insert a prefetch instruction if supported; otherwise, it is a noop.
5565 Prefetches have no effect on the behavior of the program but can change its
5566 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5567
5568<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5569<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5570 specifier determining if the fetch should be for a read (0) or write (1),
5571 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5572 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5573 and <tt>locality</tt> arguments must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5574
5575<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5576<p>This intrinsic does not modify the behavior of the program. In particular,
5577 prefetches cannot trap and do not produce a value. On targets that support
5578 this intrinsic, the prefetch can provide hints to the processor cache for
5579 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]5580
5581</div>
5582
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5583<!-- _______________________________________________________________________ -->
5584<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5585 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5586</div>
5587
5588<div class="doc_text">
5589
5590<h5>Syntax:</h5>
5591<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]5592 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5593</pre>
5594
5595<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5596<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5597 Counter (PC) in a region of code to simulators and other tools. The method
5598 is target specific, but it is expected that the marker will use exported
5599 symbols to transmit the PC of the marker. The marker makes no guarantees
5600 that it will remain with any specific instruction after optimizations. It is
5601 possible that the presence of a marker will inhibit optimizations. The
5602 intended use is to be inserted after optimizations to allow correlations of
5603 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5604
5605<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5606<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5607
5608<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5609<p>This intrinsic does not modify the behavior of the program. Backends that do
5610 not support this intrinisic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]5611
5612</div>
5613
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5614<!-- _______________________________________________________________________ -->
5615<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5616 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5617</div>
5618
5619<div class="doc_text">
5620
5621<h5>Syntax:</h5>
5622<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5623 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5624</pre>
5625
5626<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5627<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5628 counter register (or similar low latency, high accuracy clocks) on those
5629 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5630 should map to RPCC. As the backing counters overflow quickly (on the order
5631 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5632
5633<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5634<p>When directly supported, reading the cycle counter should not modify any
5635 memory. Implementations are allowed to either return a application specific
5636 value or a system wide value. On backends without support, this is lowered
5637 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]5638
5639</div>
5640
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5641<!-- ======================================================================= -->
5642<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5643 <a name="int_libc">Standard C Library Intrinsics</a>
5644</div>
5645
5646<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5647
5648<p>LLVM provides intrinsics for a few important standard C library functions.
5649 These intrinsics allow source-language front-ends to pass information about
5650 the alignment of the pointer arguments to the code generator, providing
5651 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5652
5653</div>
5654
5655<!-- _______________________________________________________________________ -->
5656<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5657 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5658</div>
5659
5660<div class="doc_text">
5661
5662<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5663<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5664 integer bit width. Not all targets support all bit widths however.</p>
5665
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5666<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5667 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5668 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5669 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5670 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5671 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5672 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5673 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5674 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5675</pre>
5676
5677<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5678<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5679 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5680
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5681<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5682 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5683
5684<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5685<p>The first argument is a pointer to the destination, the second is a pointer
5686 to the source. The third argument is an integer argument specifying the
5687 number of bytes to copy, and the fourth argument is the alignment of the
5688 source and destination locations.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5689
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5690<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5691 then the caller guarantees that both the source and destination pointers are
5692 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5693
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5694<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5695<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5696 source location to the destination location, which are not allowed to
5697 overlap. It copies "len" bytes of memory over. If the argument is known to
5698 be aligned to some boundary, this can be specified as the fourth argument,
5699 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5700
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]5701</div>
5702
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5703<!-- _______________________________________________________________________ -->
5704<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5705 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5706</div>
5707
5708<div class="doc_text">
5709
5710<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5711<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5712 width. Not all targets support all bit widths however.</p>
5713
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5714<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5715 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5716 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5717 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5718 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5719 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5720 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5721 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5722 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5723</pre>
5724
5725<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5726<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5727 source location to the destination location. It is similar to the
5728 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5729 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5730
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5731<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5732 intrinsics do not return a value, and takes an extra alignment argument.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5733
5734<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5735<p>The first argument is a pointer to the destination, the second is a pointer
5736 to the source. The third argument is an integer argument specifying the
5737 number of bytes to copy, and the fourth argument is the alignment of the
5738 source and destination locations.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5739
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5740<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5741 then the caller guarantees that the source and destination pointers are
5742 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5743
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5744<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5745<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5746 source location to the destination location, which may overlap. It copies
5747 "len" bytes of memory over. If the argument is known to be aligned to some
5748 boundary, this can be specified as the fourth argument, otherwise it should
5749 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5750
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5751</div>
5752
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5753<!-- _______________________________________________________________________ -->
5754<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5755 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5756</div>
5757
5758<div class="doc_text">
5759
5760<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5761<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5762 width. Not all targets support all bit widths however.</p>
5763
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5764<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5765 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5766 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]5767 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5768 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5769 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5770 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5771 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5772 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5773</pre>
5774
5775<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5776<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5777 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5778
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5779<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5780 intrinsic does not return a value, and takes an extra alignment argument.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5781
5782<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5783<p>The first argument is a pointer to the destination to fill, the second is the
5784 byte value to fill it with, the third argument is an integer argument
5785 specifying the number of bytes to fill, and the fourth argument is the known
5786 alignment of destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5787
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5788<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5789 then the caller guarantees that the destination pointer is aligned to that
5790 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5791
5792<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5793<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5794 at the destination location. If the argument is known to be aligned to some
5795 boundary, this can be specified as the fourth argument, otherwise it should
5796 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5797
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5798</div>
5799
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5800<!-- _______________________________________________________________________ -->
5801<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5802 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5803</div>
5804
5805<div class="doc_text">
5806
5807<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5808<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5809 floating point or vector of floating point type. Not all targets support all
5810 types however.</p>
5811
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5812<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5813 declare float @llvm.sqrt.f32(float %Val)
5814 declare double @llvm.sqrt.f64(double %Val)
5815 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5816 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5817 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5818</pre>
5819
5820<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5821<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5822 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5823 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5824 behavior for negative numbers other than -0.0 (which allows for better
5825 optimization, because there is no need to worry about errno being
5826 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]5827
5828<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5829<p>The argument and return value are floating point numbers of the same
5830 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5831
5832<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5833<p>This function returns the sqrt of the specified operand if it is a
5834 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5835
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5836</div>
5837
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5838<!-- _______________________________________________________________________ -->
5839<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5840 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5841</div>
5842
5843<div class="doc_text">
5844
5845<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5846<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5847 floating point or vector of floating point type. Not all targets support all
5848 types however.</p>
5849
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5850<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5851 declare float @llvm.powi.f32(float %Val, i32 %power)
5852 declare double @llvm.powi.f64(double %Val, i32 %power)
5853 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5854 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5855 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5856</pre>
5857
5858<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5859<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5860 specified (positive or negative) power. The order of evaluation of
5861 multiplications is not defined. When a vector of floating point type is
5862 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5863
5864<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5865<p>The second argument is an integer power, and the first is a value to raise to
5866 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5867
5868<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5869<p>This function returns the first value raised to the second power with an
5870 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5871
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5872</div>
5873
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5874<!-- _______________________________________________________________________ -->
5875<div class="doc_subsubsection">
5876 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5877</div>
5878
5879<div class="doc_text">
5880
5881<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5882<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5883 floating point or vector of floating point type. Not all targets support all
5884 types however.</p>
5885
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5886<pre>
5887 declare float @llvm.sin.f32(float %Val)
5888 declare double @llvm.sin.f64(double %Val)
5889 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5890 declare fp128 @llvm.sin.f128(fp128 %Val)
5891 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5892</pre>
5893
5894<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5896
5897<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5898<p>The argument and return value are floating point numbers of the same
5899 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5900
5901<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5902<p>This function returns the sine of the specified operand, returning the same
5903 values as the libm <tt>sin</tt> functions would, and handles error conditions
5904 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5905
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5906</div>
5907
5908<!-- _______________________________________________________________________ -->
5909<div class="doc_subsubsection">
5910 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5911</div>
5912
5913<div class="doc_text">
5914
5915<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5916<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5917 floating point or vector of floating point type. Not all targets support all
5918 types however.</p>
5919
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5920<pre>
5921 declare float @llvm.cos.f32(float %Val)
5922 declare double @llvm.cos.f64(double %Val)
5923 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5924 declare fp128 @llvm.cos.f128(fp128 %Val)
5925 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5926</pre>
5927
5928<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5929<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5930
5931<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5932<p>The argument and return value are floating point numbers of the same
5933 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5934
5935<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5936<p>This function returns the cosine of the specified operand, returning the same
5937 values as the libm <tt>cos</tt> functions would, and handles error conditions
5938 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5939
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5940</div>
5941
5942<!-- _______________________________________________________________________ -->
5943<div class="doc_subsubsection">
5944 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5945</div>
5946
5947<div class="doc_text">
5948
5949<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5950<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5951 floating point or vector of floating point type. Not all targets support all
5952 types however.</p>
5953
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5954<pre>
5955 declare float @llvm.pow.f32(float %Val, float %Power)
5956 declare double @llvm.pow.f64(double %Val, double %Power)
5957 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5958 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5959 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5960</pre>
5961
5962<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5963<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5964 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5965
5966<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5967<p>The second argument is a floating point power, and the first is a value to
5968 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5969
5970<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5971<p>This function returns the first value raised to the second power, returning
5972 the same values as the libm <tt>pow</tt> functions would, and handles error
5973 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5974
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5975</div>
5976
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5977<!-- ======================================================================= -->
5978<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5979 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5980</div>
5981
5982<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5983
5984<p>LLVM provides intrinsics for a few important bit manipulation operations.
5985 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5986
5987</div>
5988
5989<!-- _______________________________________________________________________ -->
5990<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5991 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5992</div>
5993
5994<div class="doc_text">
5995
5996<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5997<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5998 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5999
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6000<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6001 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6002 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6003 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6004</pre>
6005
6006<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6007<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6008 values with an even number of bytes (positive multiple of 16 bits). These
6009 are useful for performing operations on data that is not in the target's
6010 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6011
6012<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6013<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6014 and low byte of the input i16 swapped. Similarly,
6015 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6016 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6017 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6018 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6019 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6020 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]6021
6022</div>
6023
6024<!-- _______________________________________________________________________ -->
6025<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]6026 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6027</div>
6028
6029<div class="doc_text">
6030
6031<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6032<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]6033 width. Not all targets support all bit widths however.</p>
6034
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6035<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6036 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6037 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6038 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6039 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6040 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6041</pre>
6042
6043<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6044<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6045 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6046
6047<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6048<p>The only argument is the value to be counted. The argument may be of any
6049 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6050
6051<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6052<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]6053
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6054</div>
6055
6056<!-- _______________________________________________________________________ -->
6057<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6058 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6059</div>
6060
6061<div class="doc_text">
6062
6063<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6064<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6065 integer bit width. Not all targets support all bit widths however.</p>
6066
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6067<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6068 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6069 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6070 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6071 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6072 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6073</pre>
6074
6075<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6076<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6077 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6078
6079<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6080<p>The only argument is the value to be counted. The argument may be of any
6081 integer type. The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6082
6083<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6084<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6085 zeros in a variable. If the src == 0 then the result is the size in bits of
6086 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6087
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]6088</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]6089
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6090<!-- _______________________________________________________________________ -->
6091<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]6092 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6093</div>
6094
6095<div class="doc_text">
6096
6097<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6098<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6099 integer bit width. Not all targets support all bit widths however.</p>
6100
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6101<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6102 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6103 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6104 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]6105 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6106 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6107</pre>
6108
6109<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6111 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6112
6113<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6114<p>The only argument is the value to be counted. The argument may be of any
6115 integer type. The return type must match the argument type.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6116
6117<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6118<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6119 zeros in a variable. If the src == 0 then the result is the size in bits of
6120 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6121
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]6122</div>
6123
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6124<!-- ======================================================================= -->
6125<div class="doc_subsection">
6126 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6127</div>
6128
6129<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6130
6131<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6132
6133</div>
6134
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6135<!-- _______________________________________________________________________ -->
6136<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6137 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6138</div>
6139
6140<div class="doc_text">
6141
6142<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6143<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]6144 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6145
6146<pre>
6147 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6148 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6149 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6150</pre>
6151
6152<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6153<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6154 a signed addition of the two arguments, and indicate whether an overflow
6155 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6156
6157<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6158<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]6159 be of integer types of any bit width, but they must have the same bit
6160 width. The second element of the result structure must be of
6161 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6162 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6163
6164<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6165<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6166 a signed addition of the two variables. They return a structure &mdash; the
6167 first element of which is the signed summation, and the second element of
6168 which is a bit specifying if the signed summation resulted in an
6169 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6170
6171<h5>Examples:</h5>
6172<pre>
6173 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6174 %sum = extractvalue {i32, i1} %res, 0
6175 %obit = extractvalue {i32, i1} %res, 1
6176 br i1 %obit, label %overflow, label %normal
6177</pre>
6178
6179</div>
6180
6181<!-- _______________________________________________________________________ -->
6182<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6183 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6184</div>
6185
6186<div class="doc_text">
6187
6188<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6189<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]6190 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6191
6192<pre>
6193 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6194 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6195 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6196</pre>
6197
6198<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6199<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6200 an unsigned addition of the two arguments, and indicate whether a carry
6201 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6202
6203<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6204<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]6205 be of integer types of any bit width, but they must have the same bit
6206 width. The second element of the result structure must be of
6207 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6208 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6209
6210<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6211<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6212 an unsigned addition of the two arguments. They return a structure &mdash;
6213 the first element of which is the sum, and the second element of which is a
6214 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6215
6216<h5>Examples:</h5>
6217<pre>
6218 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6219 %sum = extractvalue {i32, i1} %res, 0
6220 %obit = extractvalue {i32, i1} %res, 1
6221 br i1 %obit, label %carry, label %normal
6222</pre>
6223
6224</div>
6225
6226<!-- _______________________________________________________________________ -->
6227<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6228 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6229</div>
6230
6231<div class="doc_text">
6232
6233<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6234<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]6235 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6236
6237<pre>
6238 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6239 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6240 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6241</pre>
6242
6243<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6244<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6245 a signed subtraction of the two arguments, and indicate whether an overflow
6246 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6247
6248<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6249<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]6250 be of integer types of any bit width, but they must have the same bit
6251 width. The second element of the result structure must be of
6252 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6253 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6254
6255<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6256<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6257 a signed subtraction of the two arguments. They return a structure &mdash;
6258 the first element of which is the subtraction, and the second element of
6259 which is a bit specifying if the signed subtraction resulted in an
6260 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6261
6262<h5>Examples:</h5>
6263<pre>
6264 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6265 %sum = extractvalue {i32, i1} %res, 0
6266 %obit = extractvalue {i32, i1} %res, 1
6267 br i1 %obit, label %overflow, label %normal
6268</pre>
6269
6270</div>
6271
6272<!-- _______________________________________________________________________ -->
6273<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6274 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6275</div>
6276
6277<div class="doc_text">
6278
6279<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6280<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]6281 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6282
6283<pre>
6284 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6285 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6286 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6287</pre>
6288
6289<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6290<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6291 an unsigned subtraction of the two arguments, and indicate whether an
6292 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6293
6294<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6295<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]6296 be of integer types of any bit width, but they must have the same bit
6297 width. The second element of the result structure must be of
6298 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6299 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6300
6301<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6302<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6303 an unsigned subtraction of the two arguments. They return a structure &mdash;
6304 the first element of which is the subtraction, and the second element of
6305 which is a bit specifying if the unsigned subtraction resulted in an
6306 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6307
6308<h5>Examples:</h5>
6309<pre>
6310 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6311 %sum = extractvalue {i32, i1} %res, 0
6312 %obit = extractvalue {i32, i1} %res, 1
6313 br i1 %obit, label %overflow, label %normal
6314</pre>
6315
6316</div>
6317
6318<!-- _______________________________________________________________________ -->
6319<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]6320 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6321</div>
6322
6323<div class="doc_text">
6324
6325<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6326<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]6327 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6328
6329<pre>
6330 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6331 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6332 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6333</pre>
6334
6335<h5>Overview:</h5>
6336
6337<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6338 a signed multiplication of the two arguments, and indicate whether an
6339 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6340
6341<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6342<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]6343 be of integer types of any bit width, but they must have the same bit
6344 width. The second element of the result structure must be of
6345 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6346 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6347
6348<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6349<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6350 a signed multiplication of the two arguments. They return a structure &mdash;
6351 the first element of which is the multiplication, and the second element of
6352 which is a bit specifying if the signed multiplication resulted in an
6353 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]6354
6355<h5>Examples:</h5>
6356<pre>
6357 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6358 %sum = extractvalue {i32, i1} %res, 0
6359 %obit = extractvalue {i32, i1} %res, 1
6360 br i1 %obit, label %overflow, label %normal
6361</pre>
6362
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]6363</div>
6364
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6365<!-- _______________________________________________________________________ -->
6366<div class="doc_subsubsection">
6367 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6368</div>
6369
6370<div class="doc_text">
6371
6372<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6373<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]6374 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6375
6376<pre>
6377 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6378 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6379 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6380</pre>
6381
6382<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6383<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6384 a unsigned multiplication of the two arguments, and indicate whether an
6385 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6386
6387<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6388<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]6389 be of integer types of any bit width, but they must have the same bit
6390 width. The second element of the result structure must be of
6391 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6392 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6393
6394<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6395<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6396 an unsigned multiplication of the two arguments. They return a structure
6397 &mdash; the first element of which is the multiplication, and the second
6398 element of which is a bit specifying if the unsigned multiplication resulted
6399 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]6400
6401<h5>Examples:</h5>
6402<pre>
6403 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6404 %sum = extractvalue {i32, i1} %res, 0
6405 %obit = extractvalue {i32, i1} %res, 1
6406 br i1 %obit, label %overflow, label %normal
6407</pre>
6408
6409</div>
6410
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6411<!-- ======================================================================= -->
6412<div class="doc_subsection">
6413 <a name="int_debugger">Debugger Intrinsics</a>
6414</div>
6415
6416<div class="doc_text">
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6417
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6418<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6419 prefix), are described in
6420 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6421 Level Debugging</a> document.</p>
6422
6423</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6424
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6425<!-- ======================================================================= -->
6426<div class="doc_subsection">
6427 <a name="int_eh">Exception Handling Intrinsics</a>
6428</div>
6429
6430<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6431
6432<p>The LLVM exception handling intrinsics (which all start with
6433 <tt>llvm.eh.</tt> prefix), are described in
6434 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6435 Handling</a> document.</p>
6436
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6437</div>
6438
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6439<!-- ======================================================================= -->
6440<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6441 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6442</div>
6443
6444<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6445
6446<p>This intrinsic makes it possible to excise one parameter, marked with
6447 the <tt>nest</tt> attribute, from a function. The result is a callable
6448 function pointer lacking the nest parameter - the caller does not need to
6449 provide a value for it. Instead, the value to use is stored in advance in a
6450 "trampoline", a block of memory usually allocated on the stack, which also
6451 contains code to splice the nest value into the argument list. This is used
6452 to implement the GCC nested function address extension.</p>
6453
6454<p>For example, if the function is
6455 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6456 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6457 follows:</p>
6458
6459<div class="doc_code">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6460<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]6461 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6462 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6463 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6464 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6465</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6466</div>
6467
6468<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6469 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6470
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6471</div>
6472
6473<!-- _______________________________________________________________________ -->
6474<div class="doc_subsubsection">
6475 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6476</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6477
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6478<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6479
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6480<h5>Syntax:</h5>
6481<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6482 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]6483</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6484
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6485<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6486<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6487 function pointer suitable for executing it.</p>
6488
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6489<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6490<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6491 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6492 sufficiently aligned block of memory; this memory is written to by the
6493 intrinsic. Note that the size and the alignment are target-specific - LLVM
6494 currently provides no portable way of determining them, so a front-end that
6495 generates this intrinsic needs to have some target-specific knowledge.
6496 The <tt>func</tt> argument must hold a function bitcast to
6497 an <tt>i8*</tt>.</p>
6498
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6499<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6500<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6501 dependent code, turning it into a function. A pointer to this function is
6502 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6503 function pointer type</a> before being called. The new function's signature
6504 is the same as that of <tt>func</tt> with any arguments marked with
6505 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6506 is allowed, and it must be of pointer type. Calling the new function is
6507 equivalent to calling <tt>func</tt> with the same argument list, but
6508 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6509 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6510 by <tt>tramp</tt> is modified, then the effect of any later call to the
6511 returned function pointer is undefined.</p>
6512
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]6513</div>
6514
6515<!-- ======================================================================= -->
6516<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6517 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6518</div>
6519
6520<div class="doc_text">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6521
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6522<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6523 hardware constructs for atomic operations and memory synchronization. This
6524 provides an interface to the hardware, not an interface to the programmer. It
6525 is aimed at a low enough level to allow any programming models or APIs
6526 (Application Programming Interfaces) which need atomic behaviors to map
6527 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6528 hardware provides a "universal IR" for source languages, it also provides a
6529 starting point for developing a "universal" atomic operation and
6530 synchronization IR.</p>
6531
6532<p>These do <em>not</em> form an API such as high-level threading libraries,
6533 software transaction memory systems, atomic primitives, and intrinsic
6534 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6535 application libraries. The hardware interface provided by LLVM should allow
6536 a clean implementation of all of these APIs and parallel programming models.
6537 No one model or paradigm should be selected above others unless the hardware
6538 itself ubiquitously does so.</p>
6539
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6540</div>
6541
6542<!-- _______________________________________________________________________ -->
6543<div class="doc_subsubsection">
6544 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6545</div>
6546<div class="doc_text">
6547<h5>Syntax:</h5>
6548<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6549 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]6550</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6551
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6552<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6553<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6554 specific pairs of memory access types.</p>
6555
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6556<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6557<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6558 The first four arguments enables a specific barrier as listed below. The
6559 fith argument specifies that the barrier applies to io or device or uncached
6560 memory.</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6561
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6562<ul>
6563 <li><tt>ll</tt>: load-load barrier</li>
6564 <li><tt>ls</tt>: load-store barrier</li>
6565 <li><tt>sl</tt>: store-load barrier</li>
6566 <li><tt>ss</tt>: store-store barrier</li>
6567 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6568</ul>
6569
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6570<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6571<p>This intrinsic causes the system to enforce some ordering constraints upon
6572 the loads and stores of the program. This barrier does not
6573 indicate <em>when</em> any events will occur, it only enforces
6574 an <em>order</em> in which they occur. For any of the specified pairs of load
6575 and store operations (f.ex. load-load, or store-load), all of the first
6576 operations preceding the barrier will complete before any of the second
6577 operations succeeding the barrier begin. Specifically the semantics for each
6578 pairing is as follows:</p>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6579
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6580<ul>
6581 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6582 after the barrier begins.</li>
6583 <li><tt>ls</tt>: All loads before the barrier must complete before any
6584 store after the barrier begins.</li>
6585 <li><tt>ss</tt>: All stores before the barrier must complete before any
6586 store after the barrier begins.</li>
6587 <li><tt>sl</tt>: All stores before the barrier must complete before any
6588 load after the barrier begins.</li>
6589</ul>
6590
6591<p>These semantics are applied with a logical "and" behavior when more than one
6592 is enabled in a single memory barrier intrinsic.</p>
6593
6594<p>Backends may implement stronger barriers than those requested when they do
6595 not support as fine grained a barrier as requested. Some architectures do
6596 not need all types of barriers and on such architectures, these become
6597 noops.</p>
6598
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6599<h5>Example:</h5>
6600<pre>
6601%ptr = malloc i32
6602 store i32 4, %ptr
6603
6604%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6605 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6606 <i>; guarantee the above finishes</i>
6607 store i32 8, %ptr <i>; before this begins</i>
6608</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6609
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6610</div>
6611
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6612<!-- _______________________________________________________________________ -->
6613<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6614 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6615</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6616
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6617<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6618
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6619<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6620<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6621 any integer bit width and for different address spaces. Not all targets
6622 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6623
6624<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6625 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6626 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6627 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6628 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]6629</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6630
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6631<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6632<p>This loads a value in memory and compares it to a given value. If they are
6633 equal, it stores a new value into the memory.</p>
6634
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6635<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6636<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6637 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6638 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6639 this integer type. While any bit width integer may be used, targets may only
6640 lower representations they support in hardware.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6641
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6642<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6643<p>This entire intrinsic must be executed atomically. It first loads the value
6644 in memory pointed to by <tt>ptr</tt> and compares it with the
6645 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6646 memory. The loaded value is yielded in all cases. This provides the
6647 equivalent of an atomic compare-and-swap operation within the SSA
6648 framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6649
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6650<h5>Examples:</h5>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6651<pre>
6652%ptr = malloc i32
6653 store i32 4, %ptr
6654
6655%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6656%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6657 <i>; yields {i32}:result1 = 4</i>
6658%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6659%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6660
6661%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6662%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6663 <i>; yields {i32}:result2 = 8</i>
6664%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6665
6666%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6667</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6668
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6669</div>
6670
6671<!-- _______________________________________________________________________ -->
6672<div class="doc_subsubsection">
6673 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6674</div>
6675<div class="doc_text">
6676<h5>Syntax:</h5>
6677
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6678<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6679 integer bit width. Not all targets support all bit widths however.</p>
6680
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6681<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6682 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6683 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6684 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6685 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]6686</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6687
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6688<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6689<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6690 the value from memory. It then stores the value in <tt>val</tt> in the memory
6691 at <tt>ptr</tt>.</p>
6692
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6693<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6694<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6695 the <tt>val</tt> argument and the result must be integers of the same bit
6696 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6697 integer type. The targets may only lower integer representations they
6698 support.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6699
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6700<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6701<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6702 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6703 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6704
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6705<h5>Examples:</h5>
6706<pre>
6707%ptr = malloc i32
6708 store i32 4, %ptr
6709
6710%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6711%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6712 <i>; yields {i32}:result1 = 4</i>
6713%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6714%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6715
6716%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6717%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6718 <i>; yields {i32}:result2 = 8</i>
6719
6720%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6721%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6722</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6723
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6724</div>
6725
6726<!-- _______________________________________________________________________ -->
6727<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6728 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6729
6730</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6731
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6732<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6733
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6734<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6735<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6736 any integer bit width. Not all targets support all bit widths however.</p>
6737
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6738<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6739 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6740 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6741 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6742 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]6743</pre>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6744
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6745<h5>Overview:</h5>
6746<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6747 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6748
6749<h5>Arguments:</h5>
6750<p>The intrinsic takes two arguments, the first a pointer to an integer value
6751 and the second an integer value. The result is also an integer value. These
6752 integer types can have any bit width, but they must all have the same bit
6753 width. The targets may only lower integer representations they support.</p>
6754
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6755<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6756<p>This intrinsic does a series of operations atomically. It first loads the
6757 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6758 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]6759
6760<h5>Examples:</h5>
6761<pre>
6762%ptr = malloc i32
6763 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6764%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6765 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6766%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6767 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6768%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6769 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6770%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6771</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6772
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]6773</div>
6774
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6775<!-- _______________________________________________________________________ -->
6776<div class="doc_subsubsection">
6777 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6778
6779</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6780
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6781<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6782
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6783<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6784<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6785 any integer bit width and for different address spaces. Not all targets
6786 support all bit widths however.</p>
6787
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6788<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6789 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6790 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6791 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6792 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]6793</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6794
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6795<h5>Overview:</h5>
6796<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6797 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6798
6799<h5>Arguments:</h5>
6800<p>The intrinsic takes two arguments, the first a pointer to an integer value
6801 and the second an integer value. The result is also an integer value. These
6802 integer types can have any bit width, but they must all have the same bit
6803 width. The targets may only lower integer representations they support.</p>
6804
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6805<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6806<p>This intrinsic does a series of operations atomically. It first loads the
6807 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6808 result to <tt>ptr</tt>. It yields the original value stored
6809 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6810
6811<h5>Examples:</h5>
6812<pre>
6813%ptr = malloc i32
6814 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6815%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6816 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6817%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6818 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6819%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6820 <i>; yields {i32}:result3 = 2</i>
6821%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6822</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6823
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6824</div>
6825
6826<!-- _______________________________________________________________________ -->
6827<div class="doc_subsubsection">
6828 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6829 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6830 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6831 <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]6832</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6833
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6834<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6835
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6836<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6837<p>These are overloaded intrinsics. You can
6838 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6839 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6840 bit width and for different address spaces. Not all targets support all bit
6841 widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6842
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6843<pre>
6844 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6845 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6846 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6847 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]6848</pre>
6849
6850<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6851 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6852 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6853 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6854 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]6855</pre>
6856
6857<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6858 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6859 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6860 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6861 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]6862</pre>
6863
6864<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6865 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6866 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6867 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6868 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]6869</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6870
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6871<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6872<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6873 the value stored in memory at <tt>ptr</tt>. It yields the original value
6874 at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6875
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6876<h5>Arguments:</h5>
6877<p>These intrinsics take two arguments, the first a pointer to an integer value
6878 and the second an integer value. The result is also an integer value. These
6879 integer types can have any bit width, but they must all have the same bit
6880 width. The targets may only lower integer representations they support.</p>
6881
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6882<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6883<p>These intrinsics does a series of operations atomically. They first load the
6884 value stored at <tt>ptr</tt>. They then do the bitwise
6885 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6886 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6887
6888<h5>Examples:</h5>
6889<pre>
6890%ptr = malloc i32
6891 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6892%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6893 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6894%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6895 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6896%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6897 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6898%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6899 <i>; yields {i32}:result3 = FF</i>
6900%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6901</pre>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6902
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6903</div>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6904
6905<!-- _______________________________________________________________________ -->
6906<div class="doc_subsubsection">
6907 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6908 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6909 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6910 <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]6911</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6912
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6913<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6914
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6915<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6916<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6917 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6918 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6919 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6920
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6921<pre>
6922 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6923 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6924 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6925 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]6926</pre>
6927
6928<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6929 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6930 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6931 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6932 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]6933</pre>
6934
6935<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6936 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6937 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6938 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6939 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]6940</pre>
6941
6942<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6943 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6944 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6945 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6946 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]6947</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6948
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6949<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6950<p>These intrinsics takes the signed or unsigned minimum or maximum of
6951 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6952 original value at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6953
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6954<h5>Arguments:</h5>
6955<p>These intrinsics take two arguments, the first a pointer to an integer value
6956 and the second an integer value. The result is also an integer value. These
6957 integer types can have any bit width, but they must all have the same bit
6958 width. The targets may only lower integer representations they support.</p>
6959
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6960<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6961<p>These intrinsics does a series of operations atomically. They first load the
6962 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6963 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6964 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6965
6966<h5>Examples:</h5>
6967<pre>
6968%ptr = malloc i32
6969 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6970%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6971 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6972%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6973 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6974%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6975 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +0000[diff] [blame]6976%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6977 <i>; yields {i32}:result3 = 8</i>
6978%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6979</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6980
Mon P Wang6a490372008-06-25 08:15:39 +0000[diff] [blame]6981</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]6982
6983<!-- ======================================================================= -->
6984<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6985 <a name="int_general">General Intrinsics</a>
6986</div>
6987
6988<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6989
6990<p>This class of intrinsics is designed to be generic and has no specific
6991 purpose.</p>
6992
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]6993</div>
6994
6995<!-- _______________________________________________________________________ -->
6996<div class="doc_subsubsection">
6997 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6998</div>
6999
7000<div class="doc_text">
7001
7002<h5>Syntax:</h5>
7003<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]7004 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]7005</pre>
7006
7007<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7008<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7009
7010<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7011<p>The first argument is a pointer to a value, the second is a pointer to a
7012 global string, the third is a pointer to a global string which is the source
7013 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7014
7015<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7016<p>This intrinsic allows annotation of local variables with arbitrary strings.
7017 This can be useful for special purpose optimizations that want to look for
7018 these annotations. These have no other defined use, they are ignored by code
7019 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7020
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7021</div>
7022
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7023<!-- _______________________________________________________________________ -->
7024<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]7025 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7026</div>
7027
7028<div class="doc_text">
7029
7030<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7031<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7032 any integer bit width.</p>
7033
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7034<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]7035 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7036 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7037 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7038 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7039 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]7040</pre>
7041
7042<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7043<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7044
7045<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7046<p>The first argument is an integer value (result of some expression), the
7047 second is a pointer to a global string, the third is a pointer to a global
7048 string which is the source file name, and the last argument is the line
7049 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7050
7051<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7052<p>This intrinsic allows annotations to be put on arbitrary expressions with
7053 arbitrary strings. This can be useful for special purpose optimizations that
7054 want to look for these annotations. These have no other defined use, they
7055 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7056
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]7057</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7058
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7059<!-- _______________________________________________________________________ -->
7060<div class="doc_subsubsection">
7061 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7062</div>
7063
7064<div class="doc_text">
7065
7066<h5>Syntax:</h5>
7067<pre>
7068 declare void @llvm.trap()
7069</pre>
7070
7071<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7072<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7073
7074<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7075<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7076
7077<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7078<p>This intrinsics is lowered to the target dependent trap instruction. If the
7079 target does not have a trap instruction, this intrinsic will be lowered to
7080 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7081
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]7082</div>
7083
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7084<!-- _______________________________________________________________________ -->
7085<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]7086 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7087</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7088
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7089<div class="doc_text">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7090
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7091<h5>Syntax:</h5>
7092<pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7093 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7094</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7095
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7096<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7097<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7098 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7099 ensure that it is placed on the stack before local variables.</p>
7100
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7101<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7103 arguments. The first argument is the value loaded from the stack
7104 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7105 that has enough space to hold the value of the guard.</p>
7106
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7107<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7108<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7109 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7110 stack. This is to ensure that if a local variable on the stack is
7111 overwritten, it will destroy the value of the guard. When the function exits,
7112 the guard on the stack is checked against the original guard. If they're
7113 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7114 function.</p>
7115
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]7116</div>
7117
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7118<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]7119<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7120<address>
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7126 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]7127 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]7128 Last modified: $Date$
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Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]7131</body>
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