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gerrit-public.fairphone.software / toolchain / llvm-project / 78f37e6d28c0b36606a055311f92c3a2e7aee50d / . / llvm / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
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>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikov546ea7e2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]29 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]30 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]31 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]32 </ol>
33 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]34 <li><a href="#typesystem">Type System</a>
35 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]36 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]37 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]39 <li><a href="#t_floating">Floating Point Types</a></li>
40 <li><a href="#t_void">Void Type</a></li>
41 <li><a href="#t_label">Label Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]42 </ol>
43 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]44 <li><a href="#t_derived">Derived Types</a>
45 <ol>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]46 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]47 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]48 <li><a href="#t_function">Function Type</a></li>
49 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]50 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]51 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]52 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]53 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]54 </ol>
55 </li>
56 </ol>
57 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]59 <ol>
60 <li><a href="#simpleconstants">Simple Constants</a>
61 <li><a href="#aggregateconstants">Aggregate Constants</a>
62 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
63 <li><a href="#undefvalues">Undefined Values</a>
64 <li><a href="#constantexprs">Constant Expressions</a>
65 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]66 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]67 <li><a href="#othervalues">Other Values</a>
68 <ol>
69 <li><a href="#inlineasm">Inline Assembler Expressions</a>
70 </ol>
71 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]72 <li><a href="#instref">Instruction Reference</a>
73 <ol>
74 <li><a href="#terminators">Terminator Instructions</a>
75 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]76 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
77 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]78 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
79 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]80 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]81 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]82 </ol>
83 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]84 <li><a href="#binaryops">Binary Operations</a>
85 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]86 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
87 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
88 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]89 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
90 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
91 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]92 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
93 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
94 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]97 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
98 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]99 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
100 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
101 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]102 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]107 <li><a href="#vectorops">Vector Operations</a>
108 <ol>
109 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
110 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
111 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]112 </ol>
113 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]114 <li><a href="#aggregateops">Aggregate Operations</a>
115 <ol>
116 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
117 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
118 </ol>
119 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]120 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]121 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
123 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
124 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]125 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
126 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
127 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]128 </ol>
129 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]130 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]131 <ol>
132 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
133 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
135 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]137 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
139 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
140 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]141 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
142 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]143 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]144 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]145 <li><a href="#otherops">Other Operations</a>
146 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]147 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
148 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]149 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
150 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]151 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]152 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]154 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]155 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]156 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]157 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]158 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]159 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]160 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]161 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]162 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
163 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
165 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
166 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]167 </ol>
168 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]169 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
170 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]171 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
172 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
173 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]174 </ol>
175 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]176 <li><a href="#int_codegen">Code Generator Intrinsics</a>
177 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]178 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
179 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
180 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
181 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
182 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
183 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
184 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]185 </ol>
186 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]187 <li><a href="#int_libc">Standard C Library Intrinsics</a>
188 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]189 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
190 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
191 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]194 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]197 </ol>
198 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]199 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]200 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]201 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]202 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
203 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
204 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]205 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]207 </ol>
208 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]209 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]210 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]211 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]212 <ol>
213 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]214 </ol>
215 </li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]216 <li><a href="#int_atomics">Atomic intrinsics</a>
217 <ol>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]218 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
219 <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
220 <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
221 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]222 </ol>
223 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]224 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]225 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]226 <li><a href="#int_var_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]227 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]228 <li><a href="#int_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]229 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]230 <li><a href="#int_trap">
231 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]232 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]233 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]234 </ol>
235 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]236</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]237
238<div class="doc_author">
239 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
240 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]241</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]242
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]243<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]244<div class="doc_section"> <a name="abstract">Abstract </a></div>
245<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]246
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]247<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]248<p>This document is a reference manual for the LLVM assembly language.
249LLVM is an SSA based representation that provides type safety,
250low-level operations, flexibility, and the capability of representing
251'all' high-level languages cleanly. It is the common code
252representation used throughout all phases of the LLVM compilation
253strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]254</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]255
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]256<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]257<div class="doc_section"> <a name="introduction">Introduction</a> </div>
258<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]259
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]260<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]261
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]262<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]263different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]264representation (suitable for fast loading by a Just-In-Time compiler),
265and as a human readable assembly language representation. This allows
266LLVM to provide a powerful intermediate representation for efficient
267compiler transformations and analysis, while providing a natural means
268to debug and visualize the transformations. The three different forms
269of LLVM are all equivalent. This document describes the human readable
270representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]271
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]272<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]273while being expressive, typed, and extensible at the same time. It
274aims to be a "universal IR" of sorts, by being at a low enough level
275that high-level ideas may be cleanly mapped to it (similar to how
276microprocessors are "universal IR's", allowing many source languages to
277be mapped to them). By providing type information, LLVM can be used as
278the target of optimizations: for example, through pointer analysis, it
279can be proven that a C automatic variable is never accessed outside of
280the current function... allowing it to be promoted to a simple SSA
281value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]282
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]283</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]284
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]285<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]286<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]287
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]288<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]289
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]290<p>It is important to note that this document describes 'well formed'
291LLVM assembly language. There is a difference between what the parser
292accepts and what is considered 'well formed'. For example, the
293following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]294
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]295<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]296<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]297%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]298</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]299</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]300
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]301<p>...because the definition of <tt>%x</tt> does not dominate all of
302its uses. The LLVM infrastructure provides a verification pass that may
303be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]304automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]305the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]306by the verifier pass indicate bugs in transformation passes or input to
307the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]308</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]309
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]310<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]312<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]313<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]314<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]315
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]316<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]317
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]318 <p>LLVM identifiers come in two basic types: global and local. Global
319 identifiers (functions, global variables) begin with the @ character. Local
320 identifiers (register names, types) begin with the % character. Additionally,
321 there are three different formats for identifiers, for different purposes:
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]322
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]323<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]324 <li>Named values are represented as a string of characters with their prefix.
325 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
326 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]327 Identifiers which require other characters in their names can be surrounded
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]328 with quotes. In this way, anything except a <tt>&quot;</tt> character can
329 be used in a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]330
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]331 <li>Unnamed values are represented as an unsigned numeric value with their
332 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]333
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]334 <li>Constants, which are described in a <a href="#constants">section about
335 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]336</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]337
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]338<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]339don't need to worry about name clashes with reserved words, and the set of
340reserved words may be expanded in the future without penalty. Additionally,
341unnamed identifiers allow a compiler to quickly come up with a temporary
342variable without having to avoid symbol table conflicts.</p>
343
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]344<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]345languages. There are keywords for different opcodes
346('<tt><a href="#i_add">add</a></tt>',
347 '<tt><a href="#i_bitcast">bitcast</a></tt>',
348 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]349href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]350and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]351none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]352
353<p>Here is an example of LLVM code to multiply the integer variable
354'<tt>%X</tt>' by 8:</p>
355
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]356<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]357
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]358<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]359<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]360%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]361</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]362</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]363
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]364<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]365
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]366<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]367<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]368%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]369</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]370</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]371
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]372<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]373
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]374<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]375<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]376<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
377<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
378%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]379</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]380</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]381
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]382<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
383important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]384
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]385<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386
387 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
388 line.</li>
389
390 <li>Unnamed temporaries are created when the result of a computation is not
391 assigned to a named value.</li>
392
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]393 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]394
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]395</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]396
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]397<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]398demonstrating instructions, we will follow an instruction with a comment that
399defines the type and name of value produced. Comments are shown in italic
400text.</p>
401
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]402</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]403
404<!-- *********************************************************************** -->
405<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
406<!-- *********************************************************************** -->
407
408<!-- ======================================================================= -->
409<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
410</div>
411
412<div class="doc_text">
413
414<p>LLVM programs are composed of "Module"s, each of which is a
415translation unit of the input programs. Each module consists of
416functions, global variables, and symbol table entries. Modules may be
417combined together with the LLVM linker, which merges function (and
418global variable) definitions, resolves forward declarations, and merges
419symbol table entries. Here is an example of the "hello world" module:</p>
420
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]421<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]422<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]423<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
424 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]425
426<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]427<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]428
429<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]430define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]431 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]432 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]433 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]434
435 <i>; Call puts function to write out the string to stdout...</i>
436 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]437 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]438 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]439 href="#i_ret">ret</a> i32 0<br>}<br>
440</pre>
441</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]442
443<p>This example is made up of a <a href="#globalvars">global variable</a>
444named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
445function, and a <a href="#functionstructure">function definition</a>
446for "<tt>main</tt>".</p>
447
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448<p>In general, a module is made up of a list of global values,
449where both functions and global variables are global values. Global values are
450represented by a pointer to a memory location (in this case, a pointer to an
451array of char, and a pointer to a function), and have one of the following <a
452href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]453
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454</div>
455
456<!-- ======================================================================= -->
457<div class="doc_subsection">
458 <a name="linkage">Linkage Types</a>
459</div>
460
461<div class="doc_text">
462
463<p>
464All Global Variables and Functions have one of the following types of linkage:
465</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]466
467<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]469 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
471 <dd>Global values with internal linkage are only directly accessible by
472 objects in the current module. In particular, linking code into a module with
473 an internal global value may cause the internal to be renamed as necessary to
474 avoid collisions. Because the symbol is internal to the module, all
475 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]476 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]477 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]478
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]479 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]481 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
482 the same name when linkage occurs. This is typically used to implement
483 inline functions, templates, or other code which must be generated in each
484 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
485 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]486 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]487
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]488 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]489
490 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
491 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]492 used for globals that may be emitted in multiple translation units, but that
493 are not guaranteed to be emitted into every translation unit that uses them.
494 One example of this are common globals in C, such as "<tt>int X;</tt>" at
495 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]496 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]497
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]499
500 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
501 pointer to array type. When two global variables with appending linkage are
502 linked together, the two global arrays are appended together. This is the
503 LLVM, typesafe, equivalent of having the system linker append together
504 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]506
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]507 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
508 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
509 until linked, if not linked, the symbol becomes null instead of being an
510 undefined reference.
511 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]512
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]513 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]514
515 <dd>If none of the above identifiers are used, the global is externally
516 visible, meaning that it participates in linkage and can be used to resolve
517 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]518 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]519</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]520
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]521 <p>
522 The next two types of linkage are targeted for Microsoft Windows platform
523 only. They are designed to support importing (exporting) symbols from (to)
524 DLLs.
525 </p>
526
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]527 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]528 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
529
530 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
531 or variable via a global pointer to a pointer that is set up by the DLL
532 exporting the symbol. On Microsoft Windows targets, the pointer name is
533 formed by combining <code>_imp__</code> and the function or variable name.
534 </dd>
535
536 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
537
538 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
539 pointer to a pointer in a DLL, so that it can be referenced with the
540 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
541 name is formed by combining <code>_imp__</code> and the function or variable
542 name.
543 </dd>
544
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]545</dl>
546
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]547<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]548variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
549variable and was linked with this one, one of the two would be renamed,
550preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
551external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]552outside of the current module.</p>
553<p>It is illegal for a function <i>declaration</i>
554to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]555or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]556<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
557linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]558</div>
559
560<!-- ======================================================================= -->
561<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]562 <a name="callingconv">Calling Conventions</a>
563</div>
564
565<div class="doc_text">
566
567<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
568and <a href="#i_invoke">invokes</a> can all have an optional calling convention
569specified for the call. The calling convention of any pair of dynamic
570caller/callee must match, or the behavior of the program is undefined. The
571following calling conventions are supported by LLVM, and more may be added in
572the future:</p>
573
574<dl>
575 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
576
577 <dd>This calling convention (the default if no other calling convention is
578 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]579 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]580 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]581 </dd>
582
583 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
584
585 <dd>This calling convention attempts to make calls as fast as possible
586 (e.g. by passing things in registers). This calling convention allows the
587 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]588 without having to conform to an externally specified ABI. Implementations of
Arnold Schwaighofer2c6b8882008-05-14 09:17:12 +0000[diff] [blame]589 this convention should allow arbitrary
590 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
591 supported. This calling convention does not support varargs and requires the
592 prototype of all callees to exactly match the prototype of the function
593 definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]594 </dd>
595
596 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
597
598 <dd>This calling convention attempts to make code in the caller as efficient
599 as possible under the assumption that the call is not commonly executed. As
600 such, these calls often preserve all registers so that the call does not break
601 any live ranges in the caller side. This calling convention does not support
602 varargs and requires the prototype of all callees to exactly match the
603 prototype of the function definition.
604 </dd>
605
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]606 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]607
608 <dd>Any calling convention may be specified by number, allowing
609 target-specific calling conventions to be used. Target specific calling
610 conventions start at 64.
611 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]612</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]613
614<p>More calling conventions can be added/defined on an as-needed basis, to
615support pascal conventions or any other well-known target-independent
616convention.</p>
617
618</div>
619
620<!-- ======================================================================= -->
621<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]622 <a name="visibility">Visibility Styles</a>
623</div>
624
625<div class="doc_text">
626
627<p>
628All Global Variables and Functions have one of the following visibility styles:
629</p>
630
631<dl>
632 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
633
634 <dd>On ELF, default visibility means that the declaration is visible to other
635 modules and, in shared libraries, means that the declared entity may be
636 overridden. On Darwin, default visibility means that the declaration is
637 visible to other modules. Default visibility corresponds to "external
638 linkage" in the language.
639 </dd>
640
641 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
642
643 <dd>Two declarations of an object with hidden visibility refer to the same
644 object if they are in the same shared object. Usually, hidden visibility
645 indicates that the symbol will not be placed into the dynamic symbol table,
646 so no other module (executable or shared library) can reference it
647 directly.
648 </dd>
649
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]650 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
651
652 <dd>On ELF, protected visibility indicates that the symbol will be placed in
653 the dynamic symbol table, but that references within the defining module will
654 bind to the local symbol. That is, the symbol cannot be overridden by another
655 module.
656 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]657</dl>
658
659</div>
660
661<!-- ======================================================================= -->
662<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]663 <a name="globalvars">Global Variables</a>
664</div>
665
666<div class="doc_text">
667
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]668<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]669instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]670an explicit section to be placed in, and may have an optional explicit alignment
671specified. A variable may be defined as "thread_local", which means that it
672will not be shared by threads (each thread will have a separated copy of the
673variable). A variable may be defined as a global "constant," which indicates
674that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]675optimization, allowing the global data to be placed in the read-only section of
676an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]677cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]678
679<p>
680LLVM explicitly allows <em>declarations</em> of global variables to be marked
681constant, even if the final definition of the global is not. This capability
682can be used to enable slightly better optimization of the program, but requires
683the language definition to guarantee that optimizations based on the
684'constantness' are valid for the translation units that do not include the
685definition.
686</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]687
688<p>As SSA values, global variables define pointer values that are in
689scope (i.e. they dominate) all basic blocks in the program. Global
690variables always define a pointer to their "content" type because they
691describe a region of memory, and all memory objects in LLVM are
692accessed through pointers.</p>
693
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]694<p>A global variable may be declared to reside in a target-specifc numbered
695address space. For targets that support them, address spaces may affect how
696optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000[diff] [blame]697the variable. The default address space is zero. The address space qualifier
698must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]699
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]700<p>LLVM allows an explicit section to be specified for globals. If the target
701supports it, it will emit globals to the section specified.</p>
702
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]703<p>An explicit alignment may be specified for a global. If not present, or if
704the alignment is set to zero, the alignment of the global is set by the target
705to whatever it feels convenient. If an explicit alignment is specified, the
706global is forced to have at least that much alignment. All alignments must be
707a power of 2.</p>
708
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]709<p>For example, the following defines a global in a numbered address space with
710an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]711
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]712<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]713<pre>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]714@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]715</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]716</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]717
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]718</div>
719
720
721<!-- ======================================================================= -->
722<div class="doc_subsection">
723 <a name="functionstructure">Functions</a>
724</div>
725
726<div class="doc_text">
727
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]728<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
729an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]730<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]731<a href="#callingconv">calling convention</a>, a return type, an optional
732<a href="#paramattrs">parameter attribute</a> for the return type, a function
733name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]734<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]735optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]736opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]737
738LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
739optional <a href="#linkage">linkage type</a>, an optional
740<a href="#visibility">visibility style</a>, an optional
741<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]742<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]743name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]744<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]745
746<p>A function definition contains a list of basic blocks, forming the CFG for
747the function. Each basic block may optionally start with a label (giving the
748basic block a symbol table entry), contains a list of instructions, and ends
749with a <a href="#terminators">terminator</a> instruction (such as a branch or
750function return).</p>
751
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]752<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]753executed on entrance to the function, and it is not allowed to have predecessor
754basic blocks (i.e. there can not be any branches to the entry block of a
755function). Because the block can have no predecessors, it also cannot have any
756<a href="#i_phi">PHI nodes</a>.</p>
757
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]758<p>LLVM allows an explicit section to be specified for functions. If the target
759supports it, it will emit functions to the section specified.</p>
760
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]761<p>An explicit alignment may be specified for a function. If not present, or if
762the alignment is set to zero, the alignment of the function is set by the target
763to whatever it feels convenient. If an explicit alignment is specified, the
764function is forced to have at least that much alignment. All alignments must be
765a power of 2.</p>
766
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]767</div>
768
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]769
770<!-- ======================================================================= -->
771<div class="doc_subsection">
772 <a name="aliasstructure">Aliases</a>
773</div>
774<div class="doc_text">
775 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov25b2e822008-03-22 08:36:14 +0000[diff] [blame]776 function, global variable, another alias or bitcast of global value). Aliases
777 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]778 optional <a href="#visibility">visibility style</a>.</p>
779
780 <h5>Syntax:</h5>
781
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]782<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]783<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]784@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]785</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]786</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]787
788</div>
789
790
791
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]792<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]793<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
794<div class="doc_text">
795 <p>The return type and each parameter of a function type may have a set of
796 <i>parameter attributes</i> associated with them. Parameter attributes are
797 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]798 a function. Parameter attributes are considered to be part of the function,
799 not of the function type, so functions with different parameter attributes
800 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]801
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]802 <p>Parameter attributes are simple keywords that follow the type specified. If
803 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]804 example:</p>
805
806<div class="doc_code">
807<pre>
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]808declare i32 @printf(i8* noalias , ...) nounwind
809declare i32 @atoi(i8*) nounwind readonly
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]810</pre>
811</div>
812
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]813 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
814 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]815
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]816 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]817 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]818 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]819 <dd>This indicates that the parameter should be zero extended just before
820 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]821
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]822 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]823 <dd>This indicates that the parameter should be sign extended just before
824 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]825
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]826 <dt><tt>inreg</tt></dt>
827 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]828 possible) during assembling function call. Support for this attribute is
829 target-specific</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]830
831 <dt><tt>byval</tt></dt>
Chris Lattner352ab9b2008-01-15 04:34:22 +0000[diff] [blame]832 <dd>This indicates that the pointer parameter should really be passed by
833 value to the function. The attribute implies that a hidden copy of the
834 pointee is made between the caller and the callee, so the callee is unable
835 to modify the value in the callee. This attribute is only valid on llvm
836 pointer arguments. It is generally used to pass structs and arrays by
837 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]838
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]839 <dt><tt>sret</tt></dt>
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]840 <dd>This indicates that the pointer parameter specifies the address of a
841 structure that is the return value of the function in the source program.
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]842 Loads and stores to the structure are assumed not to trap.
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]843 May only be applied to the first parameter.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]844
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]845 <dt><tt>noalias</tt></dt>
Owen Anderson61101282008-02-18 04:09:01 +0000[diff] [blame]846 <dd>This indicates that the parameter does not alias any global or any other
847 parameter. The caller is responsible for ensuring that this is the case,
848 usually by placing the value in a stack allocation.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]849
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]850 <dt><tt>noreturn</tt></dt>
851 <dd>This function attribute indicates that the function never returns. This
852 indicates to LLVM that every call to this function should be treated as if
853 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]854
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]855 <dt><tt>nounwind</tt></dt>
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]856 <dd>This function attribute indicates that no exceptions unwind out of the
857 function. Usually this is because the function makes no use of exceptions,
858 but it may also be that the function catches any exceptions thrown when
859 executing it.</dd>
860
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]861 <dt><tt>nest</tt></dt>
862 <dd>This indicates that the parameter can be excised using the
863 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]864 <dt><tt>readonly</tt></dt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]865 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]866 except for producing a return value or throwing an exception. The value
867 returned must only depend on the function arguments and/or global variables.
868 It may use values obtained by dereferencing pointers.</dd>
869 <dt><tt>readnone</tt></dt>
870 <dd>A <tt>readnone</tt> function has the same restrictions as a <tt>readonly</tt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]871 function, but in addition it is not allowed to dereference any pointer arguments
872 or global variables.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]873 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]874
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]875</div>
876
877<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]878<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]879 <a name="gc">Garbage Collector Names</a>
880</div>
881
882<div class="doc_text">
883<p>Each function may specify a garbage collector name, which is simply a
884string.</p>
885
886<div class="doc_code"><pre
887>define void @f() gc "name" { ...</pre></div>
888
889<p>The compiler declares the supported values of <i>name</i>. Specifying a
890collector which will cause the compiler to alter its output in order to support
891the named garbage collection algorithm.</p>
892</div>
893
894<!-- ======================================================================= -->
895<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]896 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]897</div>
898
899<div class="doc_text">
900<p>
901Modules may contain "module-level inline asm" blocks, which corresponds to the
902GCC "file scope inline asm" blocks. These blocks are internally concatenated by
903LLVM and treated as a single unit, but may be separated in the .ll file if
904desired. The syntax is very simple:
905</p>
906
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]907<div class="doc_code">
908<pre>
909module asm "inline asm code goes here"
910module asm "more can go here"
911</pre>
912</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]913
914<p>The strings can contain any character by escaping non-printable characters.
915 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
916 for the number.
917</p>
918
919<p>
920 The inline asm code is simply printed to the machine code .s file when
921 assembly code is generated.
922</p>
923</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="datalayout">Data Layout</a>
928</div>
929
930<div class="doc_text">
931<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]932data is to be laid out in memory. The syntax for the data layout is simply:</p>
933<pre> target datalayout = "<i>layout specification</i>"</pre>
934<p>The <i>layout specification</i> consists of a list of specifications
935separated by the minus sign character ('-'). Each specification starts with a
936letter and may include other information after the letter to define some
937aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]938<dl>
939 <dt><tt>E</tt></dt>
940 <dd>Specifies that the target lays out data in big-endian form. That is, the
941 bits with the most significance have the lowest address location.</dd>
942 <dt><tt>e</tt></dt>
943 <dd>Specifies that hte target lays out data in little-endian form. That is,
944 the bits with the least significance have the lowest address location.</dd>
945 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
946 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
947 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
948 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
949 too.</dd>
950 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
951 <dd>This specifies the alignment for an integer type of a given bit
952 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
953 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
954 <dd>This specifies the alignment for a vector type of a given bit
955 <i>size</i>.</dd>
956 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
957 <dd>This specifies the alignment for a floating point type of a given bit
958 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
959 (double).</dd>
960 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
961 <dd>This specifies the alignment for an aggregate type of a given bit
962 <i>size</i>.</dd>
963</dl>
964<p>When constructing the data layout for a given target, LLVM starts with a
965default set of specifications which are then (possibly) overriden by the
966specifications in the <tt>datalayout</tt> keyword. The default specifications
967are given in this list:</p>
968<ul>
969 <li><tt>E</tt> - big endian</li>
970 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
971 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
972 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
973 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
974 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
975 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
976 alignment of 64-bits</li>
977 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
978 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
979 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
980 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
981 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
982</ul>
983<p>When llvm is determining the alignment for a given type, it uses the
984following rules:
985<ol>
986 <li>If the type sought is an exact match for one of the specifications, that
987 specification is used.</li>
988 <li>If no match is found, and the type sought is an integer type, then the
989 smallest integer type that is larger than the bitwidth of the sought type is
990 used. If none of the specifications are larger than the bitwidth then the the
991 largest integer type is used. For example, given the default specifications
992 above, the i7 type will use the alignment of i8 (next largest) while both
993 i65 and i256 will use the alignment of i64 (largest specified).</li>
994 <li>If no match is found, and the type sought is a vector type, then the
995 largest vector type that is smaller than the sought vector type will be used
996 as a fall back. This happens because <128 x double> can be implemented in
997 terms of 64 <2 x double>, for example.</li>
998</ol>
999</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1000
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1001<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1002<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1003<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1004
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1005<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1006
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1007<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1008intermediate representation. Being typed enables a number of
1009optimizations to be performed on the IR directly, without having to do
1010extra analyses on the side before the transformation. A strong type
1011system makes it easier to read the generated code and enables novel
1012analyses and transformations that are not feasible to perform on normal
1013three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1014
1015</div>
1016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1017<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1018<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1019Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1020<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1021<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1022classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1023
1024<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1025 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1026 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1027 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1028 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1029 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1030 </tr>
1031 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1032 <td><a href="#t_floating">floating point</a></td>
1033 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1034 </tr>
1035 <tr>
1036 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1037 <td><a href="#t_integer">integer</a>,
1038 <a href="#t_floating">floating point</a>,
1039 <a href="#t_pointer">pointer</a>,
1040 <a href="#t_vector">vector</a>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1041 <a href="#t_struct">structure</a>,
1042 <a href="#t_array">array</a>,
Dan Gohmanda52d212008-05-23 22:50:26 +0000[diff] [blame]1043 <a href="#t_label">label</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1044 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1045 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1046 <tr>
1047 <td><a href="#t_primitive">primitive</a></td>
1048 <td><a href="#t_label">label</a>,
1049 <a href="#t_void">void</a>,
1050 <a href="#t_integer">integer</a>,
1051 <a href="#t_floating">floating point</a>.</td>
1052 </tr>
1053 <tr>
1054 <td><a href="#t_derived">derived</a></td>
1055 <td><a href="#t_integer">integer</a>,
1056 <a href="#t_array">array</a>,
1057 <a href="#t_function">function</a>,
1058 <a href="#t_pointer">pointer</a>,
1059 <a href="#t_struct">structure</a>,
1060 <a href="#t_pstruct">packed structure</a>,
1061 <a href="#t_vector">vector</a>,
1062 <a href="#t_opaque">opaque</a>.
1063 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1064 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1065</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1066
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1067<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1068most important. Values of these types are the only ones which can be
1069produced by instructions, passed as arguments, or used as operands to
Dan Gohman34d1c0d2008-05-23 21:53:15 +0000[diff] [blame]1070instructions.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1071</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1072
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1073<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1074<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1075
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1076<div class="doc_text">
1077<p>The primitive types are the fundamental building blocks of the LLVM
1078system.</p>
1079
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1080</div>
1081
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1082<!-- _______________________________________________________________________ -->
1083<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1084
1085<div class="doc_text">
1086 <table>
1087 <tbody>
1088 <tr><th>Type</th><th>Description</th></tr>
1089 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1090 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1091 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1092 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1093 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1094 </tbody>
1095 </table>
1096</div>
1097
1098<!-- _______________________________________________________________________ -->
1099<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1100
1101<div class="doc_text">
1102<h5>Overview:</h5>
1103<p>The void type does not represent any value and has no size.</p>
1104
1105<h5>Syntax:</h5>
1106
1107<pre>
1108 void
1109</pre>
1110</div>
1111
1112<!-- _______________________________________________________________________ -->
1113<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1114
1115<div class="doc_text">
1116<h5>Overview:</h5>
1117<p>The label type represents code labels.</p>
1118
1119<h5>Syntax:</h5>
1120
1121<pre>
1122 label
1123</pre>
1124</div>
1125
1126
1127<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1128<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1129
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1130<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1131
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1132<p>The real power in LLVM comes from the derived types in the system.
1133This is what allows a programmer to represent arrays, functions,
1134pointers, and other useful types. Note that these derived types may be
1135recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1136
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1137</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1138
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1139<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1140<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1141
1142<div class="doc_text">
1143
1144<h5>Overview:</h5>
1145<p>The integer type is a very simple derived type that simply specifies an
1146arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11472^23-1 (about 8 million) can be specified.</p>
1148
1149<h5>Syntax:</h5>
1150
1151<pre>
1152 iN
1153</pre>
1154
1155<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1156value.</p>
1157
1158<h5>Examples:</h5>
1159<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1160 <tbody>
1161 <tr>
1162 <td><tt>i1</tt></td>
1163 <td>a single-bit integer.</td>
1164 </tr><tr>
1165 <td><tt>i32</tt></td>
1166 <td>a 32-bit integer.</td>
1167 </tr><tr>
1168 <td><tt>i1942652</tt></td>
1169 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1170 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1171 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1172</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1173</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1174
1175<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1176<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1177
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1178<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1180<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1181
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1182<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1183sequentially in memory. The array type requires a size (number of
1184elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1185
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1186<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1187
1188<pre>
1189 [&lt;# elements&gt; x &lt;elementtype&gt;]
1190</pre>
1191
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1192<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1193be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1194
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1195<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1196<table class="layout">
1197 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1198 <td class="left"><tt>[40 x i32]</tt></td>
1199 <td class="left">Array of 40 32-bit integer values.</td>
1200 </tr>
1201 <tr class="layout">
1202 <td class="left"><tt>[41 x i32]</tt></td>
1203 <td class="left">Array of 41 32-bit integer values.</td>
1204 </tr>
1205 <tr class="layout">
1206 <td class="left"><tt>[4 x i8]</tt></td>
1207 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1208 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1209</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1210<p>Here are some examples of multidimensional arrays:</p>
1211<table class="layout">
1212 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1213 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1214 <td class="left">3x4 array of 32-bit integer values.</td>
1215 </tr>
1216 <tr class="layout">
1217 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1218 <td class="left">12x10 array of single precision floating point values.</td>
1219 </tr>
1220 <tr class="layout">
1221 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1222 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1223 </tr>
1224</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1225
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1226<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1227length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1228LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1229As a special case, however, zero length arrays are recognized to be variable
1230length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1231type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1232
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1233</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1235<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1236<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1237<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1238
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1239<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1240
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1241<p>The function type can be thought of as a function signature. It
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1242consists of a return type and a list of formal parameter types. The
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1243return type of a function type is a scalar type, a void type, or a struct type.
Devang Patel9c1f8b12008-03-24 20:52:42 +0000[diff] [blame]1244If the return type is a struct type then all struct elements must be of first
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1245class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1247<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1248
1249<pre>
1250 &lt;returntype list&gt; (&lt;parameter list&gt;)
1251</pre>
1252
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1253<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]1254specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1255which indicates that the function takes a variable number of arguments.
1256Variable argument functions can access their arguments with the <a
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1257 href="#int_varargs">variable argument handling intrinsic</a> functions.
1258'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1259<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1260
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1261<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1262<table class="layout">
1263 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1264 <td class="left"><tt>i32 (i32)</tt></td>
1265 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1266 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1267 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1268 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1269 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1270 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1271 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1272 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1273 <tt>float</tt>.
1274 </td>
1275 </tr><tr class="layout">
1276 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1277 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1278 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1279 which returns an integer. This is the signature for <tt>printf</tt> in
1280 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1281 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1282 </tr><tr class="layout">
1283 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel8dec6c22008-03-24 18:10:52 +0000[diff] [blame]1284 <td class="left">A function taking an <tt>i32></tt>, returning two
1285 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1286 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1287 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1288</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1289
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1290</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1291<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1292<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1293<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1294<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1295<p>The structure type is used to represent a collection of data members
1296together in memory. The packing of the field types is defined to match
1297the ABI of the underlying processor. The elements of a structure may
1298be any type that has a size.</p>
1299<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1300and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1301field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1302instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1303<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1304<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1305<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1306<table class="layout">
1307 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1308 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1309 <td class="left">A triple of three <tt>i32</tt> values</td>
1310 </tr><tr class="layout">
1311 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1312 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1313 second element is a <a href="#t_pointer">pointer</a> to a
1314 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1315 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1316 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1317</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1318</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1319
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1320<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1321<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1322</div>
1323<div class="doc_text">
1324<h5>Overview:</h5>
1325<p>The packed structure type is used to represent a collection of data members
1326together in memory. There is no padding between fields. Further, the alignment
1327of a packed structure is 1 byte. The elements of a packed structure may
1328be any type that has a size.</p>
1329<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1330and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1331field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1332instruction.</p>
1333<h5>Syntax:</h5>
1334<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1335<h5>Examples:</h5>
1336<table class="layout">
1337 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1338 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1339 <td class="left">A triple of three <tt>i32</tt> values</td>
1340 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1341 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1342 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1343 second element is a <a href="#t_pointer">pointer</a> to a
1344 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1345 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1346 </tr>
1347</table>
1348</div>
1349
1350<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1351<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1352<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1353<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1354<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1355reference to another object, which must live in memory. Pointer types may have
1356an optional address space attribute defining the target-specific numbered
1357address space where the pointed-to object resides. The default address space is
1358zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1359<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1360<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1361<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1362<table class="layout">
1363 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1364 <td class="left"><tt>[4x i32]*</tt></td>
1365 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1366 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1367 </tr>
1368 <tr class="layout">
1369 <td class="left"><tt>i32 (i32 *) *</tt></td>
1370 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1371 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1372 <tt>i32</tt>.</td>
1373 </tr>
1374 <tr class="layout">
1375 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1376 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1377 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1378 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1379</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1380</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1381
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1382<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1383<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1384<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1385
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1386<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1387
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1388<p>A vector type is a simple derived type that represents a vector
1389of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1390are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1391A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1392elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1393of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1394considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1395
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1396<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1397
1398<pre>
1399 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1400</pre>
1401
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1402<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1403be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1404
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1405<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1406
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1407<table class="layout">
1408 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1409 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1410 <td class="left">Vector of 4 32-bit integer values.</td>
1411 </tr>
1412 <tr class="layout">
1413 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1414 <td class="left">Vector of 8 32-bit floating-point values.</td>
1415 </tr>
1416 <tr class="layout">
1417 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1418 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1419 </tr>
1420</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1421</div>
1422
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1423<!-- _______________________________________________________________________ -->
1424<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1425<div class="doc_text">
1426
1427<h5>Overview:</h5>
1428
1429<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1430corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1431In LLVM, opaque types can eventually be resolved to any type (not just a
1432structure type).</p>
1433
1434<h5>Syntax:</h5>
1435
1436<pre>
1437 opaque
1438</pre>
1439
1440<h5>Examples:</h5>
1441
1442<table class="layout">
1443 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1444 <td class="left"><tt>opaque</tt></td>
1445 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1446 </tr>
1447</table>
1448</div>
1449
1450
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1451<!-- *********************************************************************** -->
1452<div class="doc_section"> <a name="constants">Constants</a> </div>
1453<!-- *********************************************************************** -->
1454
1455<div class="doc_text">
1456
1457<p>LLVM has several different basic types of constants. This section describes
1458them all and their syntax.</p>
1459
1460</div>
1461
1462<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1463<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1464
1465<div class="doc_text">
1466
1467<dl>
1468 <dt><b>Boolean constants</b></dt>
1469
1470 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1471 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1472 </dd>
1473
1474 <dt><b>Integer constants</b></dt>
1475
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1476 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1477 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1478 integer types.
1479 </dd>
1480
1481 <dt><b>Floating point constants</b></dt>
1482
1483 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1484 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]1485 notation (see below). The assembler requires the exact decimal value of
1486 a floating-point constant. For example, the assembler accepts 1.25 but
1487 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1488 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1489
1490 <dt><b>Null pointer constants</b></dt>
1491
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1492 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1493 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1494
1495</dl>
1496
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1497<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1498of floating point constants. For example, the form '<tt>double
14990x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
15004.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1501(and the only time that they are generated by the disassembler) is when a
1502floating point constant must be emitted but it cannot be represented as a
1503decimal floating point number. For example, NaN's, infinities, and other
1504special values are represented in their IEEE hexadecimal format so that
1505assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1506
1507</div>
1508
1509<!-- ======================================================================= -->
1510<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1511</div>
1512
1513<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1514<p>Aggregate constants arise from aggregation of simple constants
1515and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1516
1517<dl>
1518 <dt><b>Structure constants</b></dt>
1519
1520 <dd>Structure constants are represented with notation similar to structure
1521 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1522 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1523 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1524 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1525 types of elements must match those specified by the type.
1526 </dd>
1527
1528 <dt><b>Array constants</b></dt>
1529
1530 <dd>Array constants are represented with notation similar to array type
1531 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1532 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1533 constants must have <a href="#t_array">array type</a>, and the number and
1534 types of elements must match those specified by the type.
1535 </dd>
1536
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1537 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1538
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1539 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1540 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1541 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1542 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1543 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1544 match those specified by the type.
1545 </dd>
1546
1547 <dt><b>Zero initialization</b></dt>
1548
1549 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1550 value to zero of <em>any</em> type, including scalar and aggregate types.
1551 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1552 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1553 initializers.
1554 </dd>
1555</dl>
1556
1557</div>
1558
1559<!-- ======================================================================= -->
1560<div class="doc_subsection">
1561 <a name="globalconstants">Global Variable and Function Addresses</a>
1562</div>
1563
1564<div class="doc_text">
1565
1566<p>The addresses of <a href="#globalvars">global variables</a> and <a
1567href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1568constants. These constants are explicitly referenced when the <a
1569href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1570href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1571file:</p>
1572
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1573<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1574<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1575@X = global i32 17
1576@Y = global i32 42
1577@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1578</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1579</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1580
1581</div>
1582
1583<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1584<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1585<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1586 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1587 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1588 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1589
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1590 <p>Undefined values indicate to the compiler that the program is well defined
1591 no matter what value is used, giving the compiler more freedom to optimize.
1592 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1593</div>
1594
1595<!-- ======================================================================= -->
1596<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1597</div>
1598
1599<div class="doc_text">
1600
1601<p>Constant expressions are used to allow expressions involving other constants
1602to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1603href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1604that does not have side effects (e.g. load and call are not supported). The
1605following is the syntax for constant expressions:</p>
1606
1607<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1608 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1609 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1610 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1611
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1612 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1613 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1614 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1615
1616 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1617 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1618 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1619
1620 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1621 <dd>Truncate a floating point constant to another floating point type. The
1622 size of CST must be larger than the size of TYPE. Both types must be
1623 floating point.</dd>
1624
1625 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1626 <dd>Floating point extend a constant to another type. The size of CST must be
1627 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1628
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1629 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1630 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1631 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1632 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1633 of the same number of elements. If the value won't fit in the integer type,
1634 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1635
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1636 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1637 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1638 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1639 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1640 of the same number of elements. If the value won't fit in the integer type,
1641 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1642
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1643 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1644 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1645 constant. TYPE must be a scalar or vector floating point type. CST must be of
1646 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1647 of the same number of elements. If the value won't fit in the floating point
1648 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1649
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1650 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1651 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1652 constant. TYPE must be a scalar or vector floating point type. CST must be of
1653 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1654 of the same number of elements. If the value won't fit in the floating point
1655 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1656
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1657 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1658 <dd>Convert a pointer typed constant to the corresponding integer constant
1659 TYPE must be an integer type. CST must be of pointer type. The CST value is
1660 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1661
1662 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1663 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1664 pointer type. CST must be of integer type. The CST value is zero extended,
1665 truncated, or unchanged to make it fit in a pointer size. This one is
1666 <i>really</i> dangerous!</dd>
1667
1668 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1669 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1670 identical (same number of bits). The conversion is done as if the CST value
1671 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1672 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1673 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1674 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1675 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1676
1677 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1678
1679 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1680 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1681 instruction, the index list may have zero or more indexes, which are required
1682 to make sense for the type of "CSTPTR".</dd>
1683
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1684 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1685
1686 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1687 constants.</dd>
1688
1689 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1690 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1691
1692 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1693 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1694
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]1695 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1696 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1697
1698 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1699 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1700
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1701 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1702
1703 <dd>Perform the <a href="#i_extractelement">extractelement
1704 operation</a> on constants.
1705
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1706 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1707
1708 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1709 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1710
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1711
1712 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1713
1714 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1715 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1716
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1717 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1718
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1719 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1720 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1721 binary</a> operations. The constraints on operands are the same as those for
1722 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1723 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1724</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1725</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1726
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1727<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1728<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1729<!-- *********************************************************************** -->
1730
1731<!-- ======================================================================= -->
1732<div class="doc_subsection">
1733<a name="inlineasm">Inline Assembler Expressions</a>
1734</div>
1735
1736<div class="doc_text">
1737
1738<p>
1739LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1740Module-Level Inline Assembly</a>) through the use of a special value. This
1741value represents the inline assembler as a string (containing the instructions
1742to emit), a list of operand constraints (stored as a string), and a flag that
1743indicates whether or not the inline asm expression has side effects. An example
1744inline assembler expression is:
1745</p>
1746
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1747<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1748<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1749i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1750</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1751</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1752
1753<p>
1754Inline assembler expressions may <b>only</b> be used as the callee operand of
1755a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1756</p>
1757
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1758<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1759<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1760%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]1761</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1762</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1763
1764<p>
1765Inline asms with side effects not visible in the constraint list must be marked
1766as having side effects. This is done through the use of the
1767'<tt>sideeffect</tt>' keyword, like so:
1768</p>
1769
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1770<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1771<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1772call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1773</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1774</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1775
1776<p>TODO: The format of the asm and constraints string still need to be
1777documented here. Constraints on what can be done (e.g. duplication, moving, etc
1778need to be documented).
1779</p>
1780
1781</div>
1782
1783<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1784<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1785<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1787<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1788
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1789<p>The LLVM instruction set consists of several different
1790classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1791instructions</a>, <a href="#binaryops">binary instructions</a>,
1792<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1793 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1794instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1795
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1796</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1798<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1799<div class="doc_subsection"> <a name="terminators">Terminator
1800Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1801
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1802<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1803
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1804<p>As mentioned <a href="#functionstructure">previously</a>, every
1805basic block in a program ends with a "Terminator" instruction, which
1806indicates which block should be executed after the current block is
1807finished. These terminator instructions typically yield a '<tt>void</tt>'
1808value: they produce control flow, not values (the one exception being
1809the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1810<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1811 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1812instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1813the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1814 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1815 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1816
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1817</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1818
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1819<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1820<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1821Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1822<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1823<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1824<pre> 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]1825 ret void <i>; Return from void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1826 ret &lt;type&gt; &lt;value&gt;, &lt;type&gt; &lt;value&gt; <i>; Return two values from a non-void function </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1827</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1828
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1830
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1831<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1832value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1833<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1834returns value(s) and then causes control flow, and one that just causes
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1835control flow to occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1836
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1837<h5>Arguments:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1838
1839<p>The '<tt>ret</tt>' instruction may return zero, one or multiple values.
1840The type of each return value must be a '<a href="#t_firstclass">first
1841class</a>' type. Note that a function is not <a href="#wellformed">well
1842formed</a> if there exists a '<tt>ret</tt>' instruction inside of the
1843function that returns values that do not match the return type of the
1844function.</p>
1845
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1846<h5>Semantics:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1847
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1848<p>When the '<tt>ret</tt>' instruction is executed, control flow
1849returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1850 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1851the instruction after the call. If the caller was an "<a
1852 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1853at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1854returns a value, that value shall set the call or invoke instruction's
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1855return value. If the instruction returns multiple values then these
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1856values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1857</a>' instruction.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1858
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1859<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1860
1861<pre>
1862 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1863 ret void <i>; Return from a void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1864 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1865</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1866</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1867<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1868<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1869<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1870<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1871<pre> 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]1872</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1873<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1874<p>The '<tt>br</tt>' instruction is used to cause control flow to
1875transfer to a different basic block in the current function. There are
1876two forms of this instruction, corresponding to a conditional branch
1877and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1878<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1879<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1880single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1881unconditional form of the '<tt>br</tt>' instruction takes a single
1882'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1883<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1884<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1885argument is evaluated. If the value is <tt>true</tt>, control flows
1886to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1887control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1888<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1889<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1890 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1891</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1892<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1893<div class="doc_subsubsection">
1894 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1895</div>
1896
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1897<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1898<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1899
1900<pre>
1901 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1902</pre>
1903
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1904<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1905
1906<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1907several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1908instruction, allowing a branch to occur to one of many possible
1909destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1910
1911
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1912<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1913
1914<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1915comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1916an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1917table is not allowed to contain duplicate constant entries.</p>
1918
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1919<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1920
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1921<p>The <tt>switch</tt> instruction specifies a table of values and
1922destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1923table is searched for the given value. If the value is found, control flow is
1924transfered to the corresponding destination; otherwise, control flow is
1925transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1926
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1927<h5>Implementation:</h5>
1928
1929<p>Depending on properties of the target machine and the particular
1930<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1931ways. For example, it could be generated as a series of chained conditional
1932branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1933
1934<h5>Example:</h5>
1935
1936<pre>
1937 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1938 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1939 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1940
1941 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1942 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1943
1944 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1945 switch i32 %val, label %otherwise [ i32 0, label %onzero
1946 i32 1, label %onone
1947 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1948</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1949</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1950
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1951<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1952<div class="doc_subsubsection">
1953 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1954</div>
1955
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1956<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1957
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1958<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1959
1960<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1961 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]1962 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1963</pre>
1964
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1965<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1966
1967<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1968function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1969'<tt>normal</tt>' label or the
1970'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1971"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1972"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1973href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1974continued at the dynamically nearest "exception" label. If the callee function
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1975returns multiple values then individual return values are only accessible through
1976a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1977
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1978<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1979
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1980<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1981
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1982<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1983 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1984 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1985 convention</a> the call should use. If none is specified, the call defaults
1986 to using C calling conventions.
1987 </li>
1988 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1989 function value being invoked. In most cases, this is a direct function
1990 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1991 an arbitrary pointer to function value.
1992 </li>
1993
1994 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1995 function to be invoked. </li>
1996
1997 <li>'<tt>function args</tt>': argument list whose types match the function
1998 signature argument types. If the function signature indicates the function
1999 accepts a variable number of arguments, the extra arguments can be
2000 specified. </li>
2001
2002 <li>'<tt>normal label</tt>': the label reached when the called function
2003 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2004
2005 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2006 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2007
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2008</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2009
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2010<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2011
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2012<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2013href="#i_call">call</a></tt>' instruction in most regards. The primary
2014difference is that it establishes an association with a label, which is used by
2015the runtime library to unwind the stack.</p>
2016
2017<p>This instruction is used in languages with destructors to ensure that proper
2018cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2019exception. Additionally, this is important for implementation of
2020'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2021
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2022<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]2023<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2024 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2025 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]2026 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2027 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2028</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2029</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2030
2031
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2032<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2033
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2034<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2035Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2036
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2037<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2038
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2039<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2040<pre>
2041 unwind
2042</pre>
2043
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2044<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2045
2046<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2047at the first callee in the dynamic call stack which used an <a
2048href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2049primarily used to implement exception handling.</p>
2050
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2051<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2052
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2053<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2054immediately halt. The dynamic call stack is then searched for the first <a
2055href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2056execution continues at the "exceptional" destination block specified by the
2057<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2058dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2059</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2060
2061<!-- _______________________________________________________________________ -->
2062
2063<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2064Instruction</a> </div>
2065
2066<div class="doc_text">
2067
2068<h5>Syntax:</h5>
2069<pre>
2070 unreachable
2071</pre>
2072
2073<h5>Overview:</h5>
2074
2075<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2076instruction is used to inform the optimizer that a particular portion of the
2077code is not reachable. This can be used to indicate that the code after a
2078no-return function cannot be reached, and other facts.</p>
2079
2080<h5>Semantics:</h5>
2081
2082<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2083</div>
2084
2085
2086
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2087<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2088<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2089<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2090<p>Binary operators are used to do most of the computation in a
Chris Lattner81f92972008-04-01 18:47:32 +0000[diff] [blame]2091program. They require two operands of the same type, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2092produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2093multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattner81f92972008-04-01 18:47:32 +0000[diff] [blame]2094The result value has the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2095<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2096</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2097<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2098<div class="doc_subsubsection">
2099 <a name="i_add">'<tt>add</tt>' Instruction</a>
2100</div>
2101
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2102<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2103
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2104<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2105
2106<pre>
2107 &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2108</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2109
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2110<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2111
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2112<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2113
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2114<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2115
2116<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2117 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2118 <a href="#t_vector">vector</a> values. Both arguments must have identical
2119 types.</p>
2120
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2122
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2123<p>The value produced is the integer or floating point sum of the two
2124operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2125
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2126<p>If an integer sum has unsigned overflow, the result returned is the
2127mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2128the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2129
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2130<p>Because LLVM integers use a two's complement representation, this
2131instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2132
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2133<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2134
2135<pre>
2136 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2137</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2138</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2139<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2140<div class="doc_subsubsection">
2141 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2142</div>
2143
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2144<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2145
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2146<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2147
2148<pre>
2149 &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2150</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2151
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2152<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2153
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2154<p>The '<tt>sub</tt>' instruction returns the difference of its two
2155operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2156
2157<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2158'<tt>neg</tt>' instruction present in most other intermediate
2159representations.</p>
2160
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2161<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2162
2163<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2164 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2165 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2166 types.</p>
2167
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2168<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2169
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2170<p>The value produced is the integer or floating point difference of
2171the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2172
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2173<p>If an integer difference has unsigned overflow, the result returned is the
2174mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2175the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2176
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2177<p>Because LLVM integers use a two's complement representation, this
2178instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2180<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2181<pre>
2182 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2183 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2184</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2185</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2186
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2187<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2188<div class="doc_subsubsection">
2189 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2190</div>
2191
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2192<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2193
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2194<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2195<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2196</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2197<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2198<p>The '<tt>mul</tt>' instruction returns the product of its two
2199operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2200
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2201<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2202
2203<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2204href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2205or <a href="#t_vector">vector</a> values. Both arguments must have identical
2206types.</p>
2207
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2208<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2209
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2210<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2211two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2212
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2213<p>If the result of an integer multiplication has unsigned overflow,
2214the result returned is the mathematical result modulo
22152<sup>n</sup>, where n is the bit width of the result.</p>
2216<p>Because LLVM integers use a two's complement representation, and the
2217result is the same width as the operands, this instruction returns the
2218correct result for both signed and unsigned integers. If a full product
2219(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2220should be sign-extended or zero-extended as appropriate to the
2221width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2222<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2223<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2224</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2225</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2226
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2227<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2228<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2229</a></div>
2230<div class="doc_text">
2231<h5>Syntax:</h5>
2232<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2233</pre>
2234<h5>Overview:</h5>
2235<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2236operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2237
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2238<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2239
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2240<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2241<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2242values. Both arguments must have identical types.</p>
2243
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2244<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2245
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2246<p>The value produced is the unsigned integer quotient of the two operands.</p>
2247<p>Note that unsigned integer division and signed integer division are distinct
2248operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2249<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2250<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2251<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2252</pre>
2253</div>
2254<!-- _______________________________________________________________________ -->
2255<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2256</a> </div>
2257<div class="doc_text">
2258<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2259<pre>
2260 &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2261</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2262
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2263<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2264
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2265<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2266operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2267
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2268<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2269
2270<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2271<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2272values. Both arguments must have identical types.</p>
2273
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2274<h5>Semantics:</h5>
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2275<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2276<p>Note that signed integer division and unsigned integer division are distinct
2277operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2278<p>Division by zero leads to undefined behavior. Overflow also leads to
2279undefined behavior; this is a rare case, but can occur, for example,
2280by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2281<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2282<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2283</pre>
2284</div>
2285<!-- _______________________________________________________________________ -->
2286<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2287Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2288<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2289<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2290<pre>
2291 &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2292</pre>
2293<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2294
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2295<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2296operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2297
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2298<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2299
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2300<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2301<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2302of floating point values. Both arguments must have identical types.</p>
2303
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2304<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2305
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2306<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2307
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2308<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2309
2310<pre>
2311 &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]2312</pre>
2313</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2314
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2315<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2316<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2317</div>
2318<div class="doc_text">
2319<h5>Syntax:</h5>
2320<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2321</pre>
2322<h5>Overview:</h5>
2323<p>The '<tt>urem</tt>' instruction returns the remainder from the
2324unsigned division of its two arguments.</p>
2325<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2326<p>The two arguments to the '<tt>urem</tt>' instruction must be
2327<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2328values. Both arguments must have identical types.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2329<h5>Semantics:</h5>
2330<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2331This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2332<p>Note that unsigned integer remainder and signed integer remainder are
2333distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2334<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2335<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2336<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2337</pre>
2338
2339</div>
2340<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2341<div class="doc_subsubsection">
2342 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2343</div>
2344
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2345<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2346
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2347<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2348
2349<pre>
2350 &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2351</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2352
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2353<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2354
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2355<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2356signed division of its two operands. This instruction can also take
2357<a href="#t_vector">vector</a> versions of the values in which case
2358the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2359
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2360<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2361
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2362<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2363<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2364values. Both arguments must have identical types.</p>
2365
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2366<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2367
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2368<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2369has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2370operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2371a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2372 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2373Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2374please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2375Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2376<p>Note that signed integer remainder and unsigned integer remainder are
2377distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2378<p>Taking the remainder of a division by zero leads to undefined behavior.
2379Overflow also leads to undefined behavior; this is a rare case, but can occur,
2380for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2381(The remainder doesn't actually overflow, but this rule lets srem be
2382implemented using instructions that return both the result of the division
2383and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2384<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2385<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2386</pre>
2387
2388</div>
2389<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2390<div class="doc_subsubsection">
2391 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2392
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2393<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2394
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2395<h5>Syntax:</h5>
2396<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2397</pre>
2398<h5>Overview:</h5>
2399<p>The '<tt>frem</tt>' instruction returns the remainder from the
2400division of its two operands.</p>
2401<h5>Arguments:</h5>
2402<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2403<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2404of floating point values. Both arguments must have identical types.</p>
2405
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2406<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2407
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2408<p>This instruction returns the <i>remainder</i> of a division.
2409The remainder has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2410
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2411<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2412
2413<pre>
2414 &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]2415</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2416</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2417
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2418<!-- ======================================================================= -->
2419<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2420Operations</a> </div>
2421<div class="doc_text">
2422<p>Bitwise binary operators are used to do various forms of
2423bit-twiddling in a program. They are generally very efficient
2424instructions and can commonly be strength reduced from other
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2425instructions. They require two operands of the same type, execute an operation on them,
2426and produce a single value. The resulting value is the same type as its operands.</p>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2427</div>
2428
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2429<!-- _______________________________________________________________________ -->
2430<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2431Instruction</a> </div>
2432<div class="doc_text">
2433<h5>Syntax:</h5>
2434<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2435</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2436
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2437<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2438
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2439<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2440the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2441
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2442<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2443
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2444<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2445 href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2446unsigned value. This instruction does not support
2447<a href="#t_vector">vector</a> operands.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2448
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2449<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2450
Chris Lattner1429e6f2008-04-01 18:45:27 +0000[diff] [blame]2451<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup> mod 2<sup>n</sup>,
2452where n is the width of the result. If <tt>var2</tt> is (statically or dynamically) negative or
2453equal to or larger than the number of bits in <tt>var1</tt>, the result is undefined.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2454
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2455<h5>Example:</h5><pre>
2456 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2457 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2458 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2459 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2460</pre>
2461</div>
2462<!-- _______________________________________________________________________ -->
2463<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2464Instruction</a> </div>
2465<div class="doc_text">
2466<h5>Syntax:</h5>
2467<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2468</pre>
2469
2470<h5>Overview:</h5>
2471<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2472operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2473
2474<h5>Arguments:</h5>
2475<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2476<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2477unsigned value. This instruction does not support
2478<a href="#t_vector">vector</a> operands.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2479
2480<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2481
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2482<p>This instruction always performs a logical shift right operation. The most
2483significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2484shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2485the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2486
2487<h5>Example:</h5>
2488<pre>
2489 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2490 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2491 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2492 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2493 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2494</pre>
2495</div>
2496
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2497<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2498<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2499Instruction</a> </div>
2500<div class="doc_text">
2501
2502<h5>Syntax:</h5>
2503<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2504</pre>
2505
2506<h5>Overview:</h5>
2507<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2508operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2509
2510<h5>Arguments:</h5>
2511<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]2512<a href="#t_integer">integer</a> type. '<tt>var2</tt>' is treated as an
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2513unsigned value. This instruction does not support
2514<a href="#t_vector">vector</a> operands.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2515
2516<h5>Semantics:</h5>
2517<p>This instruction always performs an arithmetic shift right operation,
2518The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2519of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2520larger than the number of bits in <tt>var1</tt>, the result is undefined.
2521</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2522
2523<h5>Example:</h5>
2524<pre>
2525 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2526 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2527 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2528 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2529 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2530</pre>
2531</div>
2532
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2533<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2534<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2535Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2536
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2537<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2538
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2539<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2540
2541<pre>
2542 &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2543</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2544
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2545<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2546
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2547<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2548its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2549
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2550<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2551
2552<p>The two arguments to the '<tt>and</tt>' instruction must be
2553<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2554values. Both arguments must have identical types.</p>
2555
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2556<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2557<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2558<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2559<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2560<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2561 <tbody>
2562 <tr>
2563 <td>In0</td>
2564 <td>In1</td>
2565 <td>Out</td>
2566 </tr>
2567 <tr>
2568 <td>0</td>
2569 <td>0</td>
2570 <td>0</td>
2571 </tr>
2572 <tr>
2573 <td>0</td>
2574 <td>1</td>
2575 <td>0</td>
2576 </tr>
2577 <tr>
2578 <td>1</td>
2579 <td>0</td>
2580 <td>0</td>
2581 </tr>
2582 <tr>
2583 <td>1</td>
2584 <td>1</td>
2585 <td>1</td>
2586 </tr>
2587 </tbody>
2588</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2589</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2590<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2591<pre>
2592 &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]2593 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2594 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2595</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2596</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2597<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2598<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2599<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2600<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2601<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2602</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2603<h5>Overview:</h5>
2604<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2605or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2606<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2607
2608<p>The two arguments to the '<tt>or</tt>' instruction must be
2609<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2610values. Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2611<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2612<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2613<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2614<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2615<table border="1" cellspacing="0" cellpadding="4">
2616 <tbody>
2617 <tr>
2618 <td>In0</td>
2619 <td>In1</td>
2620 <td>Out</td>
2621 </tr>
2622 <tr>
2623 <td>0</td>
2624 <td>0</td>
2625 <td>0</td>
2626 </tr>
2627 <tr>
2628 <td>0</td>
2629 <td>1</td>
2630 <td>1</td>
2631 </tr>
2632 <tr>
2633 <td>1</td>
2634 <td>0</td>
2635 <td>1</td>
2636 </tr>
2637 <tr>
2638 <td>1</td>
2639 <td>1</td>
2640 <td>1</td>
2641 </tr>
2642 </tbody>
2643</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2644</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2645<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2646<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2647 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2648 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2649</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2650</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2651<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2652<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2653Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2654<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2655<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2656<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2657</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2658<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2659<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2660or of its two operands. The <tt>xor</tt> is used to implement the
2661"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2662<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2663<p>The two arguments to the '<tt>xor</tt>' instruction must be
2664<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2665values. Both arguments must have identical types.</p>
2666
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2667<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]2668
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2669<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2670<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2671<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2672<table border="1" cellspacing="0" cellpadding="4">
2673 <tbody>
2674 <tr>
2675 <td>In0</td>
2676 <td>In1</td>
2677 <td>Out</td>
2678 </tr>
2679 <tr>
2680 <td>0</td>
2681 <td>0</td>
2682 <td>0</td>
2683 </tr>
2684 <tr>
2685 <td>0</td>
2686 <td>1</td>
2687 <td>1</td>
2688 </tr>
2689 <tr>
2690 <td>1</td>
2691 <td>0</td>
2692 <td>1</td>
2693 </tr>
2694 <tr>
2695 <td>1</td>
2696 <td>1</td>
2697 <td>0</td>
2698 </tr>
2699 </tbody>
2700</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2701</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2702<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2703<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2704<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2705 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2706 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2707 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2708</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2709</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2710
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2711<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2712<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2713 <a name="vectorops">Vector Operations</a>
2714</div>
2715
2716<div class="doc_text">
2717
2718<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2719target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2720vector-specific operations needed to process vectors effectively. While LLVM
2721does directly support these vector operations, many sophisticated algorithms
2722will want to use target-specific intrinsics to take full advantage of a specific
2723target.</p>
2724
2725</div>
2726
2727<!-- _______________________________________________________________________ -->
2728<div class="doc_subsubsection">
2729 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2730</div>
2731
2732<div class="doc_text">
2733
2734<h5>Syntax:</h5>
2735
2736<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2737 &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]2738</pre>
2739
2740<h5>Overview:</h5>
2741
2742<p>
2743The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2744element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2745</p>
2746
2747
2748<h5>Arguments:</h5>
2749
2750<p>
2751The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2752value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2753an index indicating the position from which to extract the element.
2754The index may be a variable.</p>
2755
2756<h5>Semantics:</h5>
2757
2758<p>
2759The result is a scalar of the same type as the element type of
2760<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2761<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2762results are undefined.
2763</p>
2764
2765<h5>Example:</h5>
2766
2767<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2768 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2769</pre>
2770</div>
2771
2772
2773<!-- _______________________________________________________________________ -->
2774<div class="doc_subsubsection">
2775 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2776</div>
2777
2778<div class="doc_text">
2779
2780<h5>Syntax:</h5>
2781
2782<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]2783 &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]2784</pre>
2785
2786<h5>Overview:</h5>
2787
2788<p>
2789The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2790element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2791</p>
2792
2793
2794<h5>Arguments:</h5>
2795
2796<p>
2797The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2798value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2799scalar value whose type must equal the element type of the first
2800operand. The third operand is an index indicating the position at
2801which to insert the value. The index may be a variable.</p>
2802
2803<h5>Semantics:</h5>
2804
2805<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2806The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2807element values are those of <tt>val</tt> except at position
2808<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2809exceeds the length of <tt>val</tt>, the results are undefined.
2810</p>
2811
2812<h5>Example:</h5>
2813
2814<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2815 %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]2816</pre>
2817</div>
2818
2819<!-- _______________________________________________________________________ -->
2820<div class="doc_subsubsection">
2821 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2822</div>
2823
2824<div class="doc_text">
2825
2826<h5>Syntax:</h5>
2827
2828<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2829 &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;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2830</pre>
2831
2832<h5>Overview:</h5>
2833
2834<p>
2835The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2836from two input vectors, returning a vector of the same type.
2837</p>
2838
2839<h5>Arguments:</h5>
2840
2841<p>
2842The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2843with types that match each other and types that match the result of the
2844instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2845of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2846</p>
2847
2848<p>
2849The shuffle mask operand is required to be a constant vector with either
2850constant integer or undef values.
2851</p>
2852
2853<h5>Semantics:</h5>
2854
2855<p>
2856The elements of the two input vectors are numbered from left to right across
2857both of the vectors. The shuffle mask operand specifies, for each element of
2858the result vector, which element of the two input registers the result element
2859gets. The element selector may be undef (meaning "don't care") and the second
2860operand may be undef if performing a shuffle from only one vector.
2861</p>
2862
2863<h5>Example:</h5>
2864
2865<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2866 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2867 &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]2868 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2869 &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.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2870</pre>
2871</div>
2872
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2873
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2874<!-- ======================================================================= -->
2875<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2876 <a name="aggregateops">Aggregate Operations</a>
2877</div>
2878
2879<div class="doc_text">
2880
2881<p>LLVM supports several instructions for working with aggregate values.
2882</p>
2883
2884</div>
2885
2886<!-- _______________________________________________________________________ -->
2887<div class="doc_subsubsection">
2888 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
2889</div>
2890
2891<div class="doc_text">
2892
2893<h5>Syntax:</h5>
2894
2895<pre>
2896 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
2897</pre>
2898
2899<h5>Overview:</h5>
2900
2901<p>
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2902The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
2903or array element from an aggregate value.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2904</p>
2905
2906
2907<h5>Arguments:</h5>
2908
2909<p>
2910The first operand of an '<tt>extractvalue</tt>' instruction is a
2911value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2912type. The operands are constant indices to specify which value to extract
2913in the same manner as indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2914'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2915</p>
2916
2917<h5>Semantics:</h5>
2918
2919<p>
2920The result is the value at the position in the aggregate specified by
2921the index operands.
2922</p>
2923
2924<h5>Example:</h5>
2925
2926<pre>
2927 %result = extractvalue {i32, float} %agg, i32 0 <i>; yields i32</i>
2928</pre>
2929</div>
2930
2931
2932<!-- _______________________________________________________________________ -->
2933<div class="doc_subsubsection">
2934 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
2935</div>
2936
2937<div class="doc_text">
2938
2939<h5>Syntax:</h5>
2940
2941<pre>
2942 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
2943</pre>
2944
2945<h5>Overview:</h5>
2946
2947<p>
2948The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2949into a struct field or array element in an aggregate.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2950</p>
2951
2952
2953<h5>Arguments:</h5>
2954
2955<p>
2956The first operand of an '<tt>insertvalue</tt>' instruction is a
2957value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
2958The second operand is a first-class value to insert.
Dan Gohman34d1c0d2008-05-23 21:53:15 +0000[diff] [blame]2959The following operands are constant indices
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2960indicating the position at which to insert the value in the same manner as
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2961indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2962'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2963The value to insert must have the same type as the value identified
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2964by the indices.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2965
2966<h5>Semantics:</h5>
2967
2968<p>
2969The result is an aggregate of the same type as <tt>val</tt>. Its
2970value is that of <tt>val</tt> except that the value at the position
Dan Gohman35a835c2008-05-13 18:16:06 +0000[diff] [blame]2971specified by the indices is that of <tt>elt</tt>.
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]2972</p>
2973
2974<h5>Example:</h5>
2975
2976<pre>
2977 %result = insertvalue {i32, float} %agg, i32 1, i32 0 <i>; yields {i32, float}</i>
2978</pre>
2979</div>
2980
2981
2982<!-- ======================================================================= -->
2983<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2984 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2985</div>
2986
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2987<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2988
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2989<p>A key design point of an SSA-based representation is how it
2990represents memory. In LLVM, no memory locations are in SSA form, which
2991makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2992allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2993
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2994</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2995
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2996<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2997<div class="doc_subsubsection">
2998 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2999</div>
3000
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3001<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3002
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3003<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3004
3005<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3006 &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]3007</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3008
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3009<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3010
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3011<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]3012heap and returns a pointer to it. The object is always allocated in the generic
3013address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3014
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3015<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3016
3017<p>The '<tt>malloc</tt>' instruction allocates
3018<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]3019bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3020appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3021number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3022If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3023be aligned to at least that boundary. If not specified, or if zero, the target can
3024choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3025
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3026<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3027
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3028<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3029
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3030<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3031a pointer is returned. The result of a zero byte allocattion is undefined. The
3032result is null if there is insufficient memory available.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3033
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3034<h5>Example:</h5>
3035
3036<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3037 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3038
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3039 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3040 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3041 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3042 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3043 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3044</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3045</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3046
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3047<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3048<div class="doc_subsubsection">
3049 <a name="i_free">'<tt>free</tt>' Instruction</a>
3050</div>
3051
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3052<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3053
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3054<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3055
3056<pre>
3057 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3058</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3059
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3060<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3061
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3062<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3063memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3064
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3065<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3066
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3067<p>'<tt>value</tt>' shall be a pointer value that points to a value
3068that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3069instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3070
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3071<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3072
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3073<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner0f103e12008-04-19 22:41:32 +0000[diff] [blame]3074after this instruction executes. If the pointer is null, the operation
3075is a noop.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3076
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3077<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3078
3079<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3080 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3081 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3082</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3083</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3084
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3085<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3086<div class="doc_subsubsection">
3087 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3088</div>
3089
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3090<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3091
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3092<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3093
3094<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3095 &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]3096</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3097
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3098<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3099
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3100<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3101currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]3102returns to its caller. The object is always allocated in the generic address
3103space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3104
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3105<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3106
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3107<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3108bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3109appropriate type to the program. If "NumElements" is specified, it is the
3110number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3111If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]3112to be aligned to at least that boundary. If not specified, or if zero, the target
3113can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3114
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3115<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3116
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3117<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3118
Chris Lattnerfe8519c2008-04-19 21:01:16 +0000[diff] [blame]3119<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3120there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3121memory is automatically released when the function returns. The '<tt>alloca</tt>'
3122instruction is commonly used to represent automatic variables that must
3123have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]3124 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3125instructions), the memory is reclaimed. Allocating zero bytes
3126is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3127
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3128<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3129
3130<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3131 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3132 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3133 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3134 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3135</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3136</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]3137
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3138<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3139<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3140Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3141<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3142<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]3143<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3144<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3145<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3146<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3147<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]3148address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]3149 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]3150marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3151the number or order of execution of this <tt>load</tt> with other
3152volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3153instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3154<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3155The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3156(that is, the alignment of the memory address). A value of 0 or an
3157omitted "align" argument means that the operation has the preferential
3158alignment for the target. It is the responsibility of the code emitter
3159to ensure that the alignment information is correct. Overestimating
3160the alignment results in an undefined behavior. Underestimating the
3161alignment may produce less efficient code. An alignment of 1 is always
3162safe.
3163</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3164<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3165<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3166<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3167<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3168 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3169 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3170 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3171</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3172</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3173<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3174<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3175Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]3176<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3177<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]3178<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3179 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]3180</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3181<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3182<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3183<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3184<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3185to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3186operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3187of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3188operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3189optimizer is not allowed to modify the number or order of execution of
3190this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3191 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3192<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3193The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]3194(that is, the alignment of the memory address). A value of 0 or an
3195omitted "align" argument means that the operation has the preferential
3196alignment for the target. It is the responsibility of the code emitter
3197to ensure that the alignment information is correct. Overestimating
3198the alignment results in an undefined behavior. Underestimating the
3199alignment may produce less efficient code. An alignment of 1 is always
3200safe.
3201</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3202<h5>Semantics:</h5>
3203<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3204at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3205<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3206<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]3207 store i32 3, i32* %ptr <i>; yields {void}</i>
3208 %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]3209</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3210</div>
3211
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]3212<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3213<div class="doc_subsubsection">
3214 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3215</div>
3216
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3217<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3218<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3219<pre>
3220 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
3221</pre>
3222
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3223<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3224
3225<p>
3226The '<tt>getelementptr</tt>' instruction is used to get the address of a
3227subelement of an aggregate data structure.</p>
3228
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3229<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3230
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3231<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3232elements of the aggregate object to index to. The actual types of the arguments
3233provided depend on the type of the first pointer argument. The
3234'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3235levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3236structure, only <tt>i32</tt> integer constants are allowed. When indexing
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]3237into an array or pointer, only integers of 32 or 64 bits are allowed; 32-bit
3238values will be sign extended to 64-bits if required.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3239
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3240<p>For example, let's consider a C code fragment and how it gets
3241compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3242
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3243<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3244<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3245struct RT {
3246 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3247 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3248 char C;
3249};
3250struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3251 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3252 double Y;
3253 struct RT Z;
3254};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3255
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3256int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3257 return &amp;s[1].Z.B[5][13];
3258}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3259</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3260</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3261
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3262<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3263
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3264<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3265<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3266%RT = type { i8 , [10 x [20 x i32]], i8 }
3267%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3268
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3269define i32* %foo(%ST* %s) {
3270entry:
3271 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3272 ret i32* %reg
3273}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3274</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3275</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3276
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3277<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3278
3279<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3280on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3281and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]3282<a href="#t_integer">integer</a> type but the value will always be sign extended
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3283to 64-bits. <a href="#t_struct">Structure</a> and <a href="#t_pstruct">packed
3284structure</a> types require <tt>i32</tt> <b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3285
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3286<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3287type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3288}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3289the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3290i8 }</tt>' type, another structure. The third index indexes into the second
3291element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3292array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3293'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3294to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3295
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3296<p>Note that it is perfectly legal to index partially through a
3297structure, returning a pointer to an inner element. Because of this,
3298the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3299
3300<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3301 define i32* %foo(%ST* %s) {
3302 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3303 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3304 %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]3305 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3306 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3307 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3308 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3309</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3310
3311<p>Note that it is undefined to access an array out of bounds: array and
3312pointer indexes must always be within the defined bounds of the array type.
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]3313The one exception for this rule is zero length arrays. These arrays are
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3314defined to be accessible as variable length arrays, which requires access
3315beyond the zero'th element.</p>
3316
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3317<p>The getelementptr instruction is often confusing. For some more insight
3318into how it works, see <a href="GetElementPtr.html">the getelementptr
3319FAQ</a>.</p>
3320
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3321<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3322
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3323<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3324 <i>; yields [12 x i8]*:aptr</i>
3325 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3326</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3327</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3328
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3329<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3330<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3331</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3332<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3333<p>The instructions in this category are the conversion instructions (casting)
3334which all take a single operand and a type. They perform various bit conversions
3335on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3336</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3337
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3338<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3339<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3340 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3341</div>
3342<div class="doc_text">
3343
3344<h5>Syntax:</h5>
3345<pre>
3346 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3347</pre>
3348
3349<h5>Overview:</h5>
3350<p>
3351The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3352</p>
3353
3354<h5>Arguments:</h5>
3355<p>
3356The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3357be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3358and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3359type. The bit size of <tt>value</tt> must be larger than the bit size of
3360<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3361
3362<h5>Semantics:</h5>
3363<p>
3364The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3365and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3366larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3367It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3368
3369<h5>Example:</h5>
3370<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3371 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3372 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3373 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3374</pre>
3375</div>
3376
3377<!-- _______________________________________________________________________ -->
3378<div class="doc_subsubsection">
3379 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3380</div>
3381<div class="doc_text">
3382
3383<h5>Syntax:</h5>
3384<pre>
3385 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3386</pre>
3387
3388<h5>Overview:</h5>
3389<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3390<tt>ty2</tt>.</p>
3391
3392
3393<h5>Arguments:</h5>
3394<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3395<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3396also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3397<tt>value</tt> must be smaller than the bit size of the destination type,
3398<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3399
3400<h5>Semantics:</h5>
3401<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]3402bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3403
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3404<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]3405
3406<h5>Example:</h5>
3407<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3408 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3409 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3410</pre>
3411</div>
3412
3413<!-- _______________________________________________________________________ -->
3414<div class="doc_subsubsection">
3415 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3416</div>
3417<div class="doc_text">
3418
3419<h5>Syntax:</h5>
3420<pre>
3421 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3422</pre>
3423
3424<h5>Overview:</h5>
3425<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3426
3427<h5>Arguments:</h5>
3428<p>
3429The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3430<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3431also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3432<tt>value</tt> must be smaller than the bit size of the destination type,
3433<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3434
3435<h5>Semantics:</h5>
3436<p>
3437The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3438bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]3439the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3440
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3441<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]3442
3443<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3444<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3445 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3446 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3447</pre>
3448</div>
3449
3450<!-- _______________________________________________________________________ -->
3451<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3452 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3453</div>
3454
3455<div class="doc_text">
3456
3457<h5>Syntax:</h5>
3458
3459<pre>
3460 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3461</pre>
3462
3463<h5>Overview:</h5>
3464<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3465<tt>ty2</tt>.</p>
3466
3467
3468<h5>Arguments:</h5>
3469<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3470 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3471cast it to. The size of <tt>value</tt> must be larger than the size of
3472<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3473<i>no-op cast</i>.</p>
3474
3475<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3476<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3477<a href="#t_floating">floating point</a> type to a smaller
3478<a href="#t_floating">floating point</a> type. If the value cannot fit within
3479the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3480
3481<h5>Example:</h5>
3482<pre>
3483 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3484 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3485</pre>
3486</div>
3487
3488<!-- _______________________________________________________________________ -->
3489<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3490 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3491</div>
3492<div class="doc_text">
3493
3494<h5>Syntax:</h5>
3495<pre>
3496 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3497</pre>
3498
3499<h5>Overview:</h5>
3500<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3501floating point value.</p>
3502
3503<h5>Arguments:</h5>
3504<p>The '<tt>fpext</tt>' instruction takes a
3505<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3506and a <a href="#t_floating">floating point</a> type to cast it to. The source
3507type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3508
3509<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3510<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3511<a href="#t_floating">floating point</a> type to a larger
3512<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3513used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3514<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]3515
3516<h5>Example:</h5>
3517<pre>
3518 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3519 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3520</pre>
3521</div>
3522
3523<!-- _______________________________________________________________________ -->
3524<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3525 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3526</div>
3527<div class="doc_text">
3528
3529<h5>Syntax:</h5>
3530<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3531 &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]3532</pre>
3533
3534<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3535<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3536unsigned integer equivalent of type <tt>ty2</tt>.
3537</p>
3538
3539<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3540<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3541scalar or vector <a href="#t_floating">floating point</a> value, and a type
3542to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3543type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3544vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3545
3546<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3547<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3548<a href="#t_floating">floating point</a> operand into the nearest (rounding
3549towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3550the results are undefined.</p>
3551
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3552<h5>Example:</h5>
3553<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3554 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3555 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3556 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3557</pre>
3558</div>
3559
3560<!-- _______________________________________________________________________ -->
3561<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3562 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3563</div>
3564<div class="doc_text">
3565
3566<h5>Syntax:</h5>
3567<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3568 &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]3569</pre>
3570
3571<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3572<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3573<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3574</p>
3575
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3576<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3577<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3578scalar or vector <a href="#t_floating">floating point</a> value, and a type
3579to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3580type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3581vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3582
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3583<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3584<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3585<a href="#t_floating">floating point</a> operand into the nearest (rounding
3586towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3587the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3588
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3589<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3590<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3591 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3592 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3593 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3594</pre>
3595</div>
3596
3597<!-- _______________________________________________________________________ -->
3598<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3599 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3600</div>
3601<div class="doc_text">
3602
3603<h5>Syntax:</h5>
3604<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3605 &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]3606</pre>
3607
3608<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3609<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3610integer and converts that value to the <tt>ty2</tt> type.</p>
3611
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3612<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3613<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3614scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3615to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3616type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3617floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3618
3619<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3620<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3621integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3622the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3623
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3624<h5>Example:</h5>
3625<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3626 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3627 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3628</pre>
3629</div>
3630
3631<!-- _______________________________________________________________________ -->
3632<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3633 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3634</div>
3635<div class="doc_text">
3636
3637<h5>Syntax:</h5>
3638<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3639 &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]3640</pre>
3641
3642<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3643<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3644integer and converts that value to the <tt>ty2</tt> type.</p>
3645
3646<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3647<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3648scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3649to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3650type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3651floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3652
3653<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3654<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3655integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3656the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3657
3658<h5>Example:</h5>
3659<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3660 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3661 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3662</pre>
3663</div>
3664
3665<!-- _______________________________________________________________________ -->
3666<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3667 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3668</div>
3669<div class="doc_text">
3670
3671<h5>Syntax:</h5>
3672<pre>
3673 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3674</pre>
3675
3676<h5>Overview:</h5>
3677<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3678the integer type <tt>ty2</tt>.</p>
3679
3680<h5>Arguments:</h5>
3681<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3682must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3683<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3684
3685<h5>Semantics:</h5>
3686<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3687<tt>ty2</tt> by interpreting the pointer value as an integer and either
3688truncating or zero extending that value to the size of the integer type. If
3689<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3690<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3691are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3692change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3693
3694<h5>Example:</h5>
3695<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3696 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3697 %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]3698</pre>
3699</div>
3700
3701<!-- _______________________________________________________________________ -->
3702<div class="doc_subsubsection">
3703 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3704</div>
3705<div class="doc_text">
3706
3707<h5>Syntax:</h5>
3708<pre>
3709 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3710</pre>
3711
3712<h5>Overview:</h5>
3713<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3714a pointer type, <tt>ty2</tt>.</p>
3715
3716<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3717<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3718value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3719<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3720
3721<h5>Semantics:</h5>
3722<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3723<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3724the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3725size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3726the size of a pointer then a zero extension is done. If they are the same size,
3727nothing is done (<i>no-op cast</i>).</p>
3728
3729<h5>Example:</h5>
3730<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3731 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3732 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3733 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3734</pre>
3735</div>
3736
3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3739 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3740</div>
3741<div class="doc_text">
3742
3743<h5>Syntax:</h5>
3744<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3745 &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]3746</pre>
3747
3748<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3749
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3750<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3751<tt>ty2</tt> without changing any bits.</p>
3752
3753<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3754
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3755<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3756a first class value, and a type to cast it to, which must also be a <a
3757 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3758and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3759type is a pointer, the destination type must also be a pointer. This
3760instruction supports bitwise conversion of vectors to integers and to vectors
3761of other types (as long as they have the same size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3762
3763<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3764<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3765<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3766this conversion. The conversion is done as if the <tt>value</tt> had been
3767stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3768converted to other pointer types with this instruction. To convert pointers to
3769other types, use the <a href="#i_inttoptr">inttoptr</a> or
3770<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3771
3772<h5>Example:</h5>
3773<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3774 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3775 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3776 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3777</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3778</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3779
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3780<!-- ======================================================================= -->
3781<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3782<div class="doc_text">
3783<p>The instructions in this category are the "miscellaneous"
3784instructions, which defy better classification.</p>
3785</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3786
3787<!-- _______________________________________________________________________ -->
3788<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3789</div>
3790<div class="doc_text">
3791<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3792<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3793</pre>
3794<h5>Overview:</h5>
3795<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
Chris Lattner1f17cce2008-04-02 00:38:26 +0000[diff] [blame]3796of its two integer or pointer operands.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3797<h5>Arguments:</h5>
3798<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3799the condition code indicating the kind of comparison to perform. It is not
3800a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3801<ol>
3802 <li><tt>eq</tt>: equal</li>
3803 <li><tt>ne</tt>: not equal </li>
3804 <li><tt>ugt</tt>: unsigned greater than</li>
3805 <li><tt>uge</tt>: unsigned greater or equal</li>
3806 <li><tt>ult</tt>: unsigned less than</li>
3807 <li><tt>ule</tt>: unsigned less or equal</li>
3808 <li><tt>sgt</tt>: signed greater than</li>
3809 <li><tt>sge</tt>: signed greater or equal</li>
3810 <li><tt>slt</tt>: signed less than</li>
3811 <li><tt>sle</tt>: signed less or equal</li>
3812</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3813<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3814<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3815<h5>Semantics:</h5>
3816<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3817the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3818yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3819<ol>
3820 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3821 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3822 </li>
3823 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3824 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3825 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3826 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3827 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3828 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3829 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3830 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3831 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3832 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3833 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3834 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3835 <li><tt>sge</tt>: interprets the operands as signed values and yields
3836 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3837 <li><tt>slt</tt>: interprets the operands as signed values and yields
3838 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3839 <li><tt>sle</tt>: interprets the operands as signed values and yields
3840 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3841</ol>
3842<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3843values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3844
3845<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3846<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3847 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3848 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3849 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3850 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3851 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3852</pre>
3853</div>
3854
3855<!-- _______________________________________________________________________ -->
3856<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3857</div>
3858<div class="doc_text">
3859<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3860<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3861</pre>
3862<h5>Overview:</h5>
3863<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3864of its floating point operands.</p>
3865<h5>Arguments:</h5>
3866<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3867the condition code indicating the kind of comparison to perform. It is not
3868a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3869<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3870 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3871 <li><tt>oeq</tt>: ordered and equal</li>
3872 <li><tt>ogt</tt>: ordered and greater than </li>
3873 <li><tt>oge</tt>: ordered and greater than or equal</li>
3874 <li><tt>olt</tt>: ordered and less than </li>
3875 <li><tt>ole</tt>: ordered and less than or equal</li>
3876 <li><tt>one</tt>: ordered and not equal</li>
3877 <li><tt>ord</tt>: ordered (no nans)</li>
3878 <li><tt>ueq</tt>: unordered or equal</li>
3879 <li><tt>ugt</tt>: unordered or greater than </li>
3880 <li><tt>uge</tt>: unordered or greater than or equal</li>
3881 <li><tt>ult</tt>: unordered or less than </li>
3882 <li><tt>ule</tt>: unordered or less than or equal</li>
3883 <li><tt>une</tt>: unordered or not equal</li>
3884 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3885 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3886</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3887<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3888<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3889<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3890<a href="#t_floating">floating point</a> typed. They must have identical
3891types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3892<h5>Semantics:</h5>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3893<p>The '<tt>fcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3894according to the condition code given as <tt>cond</tt>. The comparison performed
3895always yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3896<ol>
3897 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3898 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3899 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3900 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3901 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3902 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3903 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3904 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3905 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3906 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3907 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3908 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3909 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3910 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3911 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3912 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3913 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3914 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3915 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3916 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3917 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3918 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3919 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3920 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3921 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3922 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3923 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3924 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3925</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3926
3927<h5>Example:</h5>
3928<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3929 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3930 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3931 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3932</pre>
3933</div>
3934
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3935<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3936<div class="doc_subsubsection">
3937 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
3938</div>
3939<div class="doc_text">
3940<h5>Syntax:</h5>
3941<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
3942</pre>
3943<h5>Overview:</h5>
3944<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
3945element-wise comparison of its two integer vector operands.</p>
3946<h5>Arguments:</h5>
3947<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
3948the condition code indicating the kind of comparison to perform. It is not
3949a value, just a keyword. The possible condition code are:
3950<ol>
3951 <li><tt>eq</tt>: equal</li>
3952 <li><tt>ne</tt>: not equal </li>
3953 <li><tt>ugt</tt>: unsigned greater than</li>
3954 <li><tt>uge</tt>: unsigned greater or equal</li>
3955 <li><tt>ult</tt>: unsigned less than</li>
3956 <li><tt>ule</tt>: unsigned less or equal</li>
3957 <li><tt>sgt</tt>: signed greater than</li>
3958 <li><tt>sge</tt>: signed greater or equal</li>
3959 <li><tt>slt</tt>: signed less than</li>
3960 <li><tt>sle</tt>: signed less or equal</li>
3961</ol>
3962<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
3963<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
3964<h5>Semantics:</h5>
3965<p>The '<tt>vicmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
3966according to the condition code given as <tt>cond</tt>. The comparison yields a
3967<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
3968identical type as the values being compared. The most significant bit in each
3969element is 1 if the element-wise comparison evaluates to true, and is 0
3970otherwise. All other bits of the result are undefined. The condition codes
3971are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
3972instruction</a>.
3973
3974<h5>Example:</h5>
3975<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3976 &lt;result&gt; = vicmp eq &lt;2 x i32&gt; &lt; i32 4, i32 0&gt;, &lt; i32 5, i32 0&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
3977 &lt;result&gt; = vicmp ult &lt;2 x i8 &gt; &lt; i8 1, i8 2&gt;, &lt; i8 2, i8 2 &gt; <i>; yields: result=&lt;2 x i8&gt; &lt; i8 -1, i8 0 &gt;</i>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]3978</pre>
3979</div>
3980
3981<!-- _______________________________________________________________________ -->
3982<div class="doc_subsubsection">
3983 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
3984</div>
3985<div class="doc_text">
3986<h5>Syntax:</h5>
3987<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt;</pre>
3988<h5>Overview:</h5>
3989<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
3990element-wise comparison of its two floating point vector operands. The output
3991elements have the same width as the input elements.</p>
3992<h5>Arguments:</h5>
3993<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
3994the condition code indicating the kind of comparison to perform. It is not
3995a value, just a keyword. The possible condition code are:
3996<ol>
3997 <li><tt>false</tt>: no comparison, always returns false</li>
3998 <li><tt>oeq</tt>: ordered and equal</li>
3999 <li><tt>ogt</tt>: ordered and greater than </li>
4000 <li><tt>oge</tt>: ordered and greater than or equal</li>
4001 <li><tt>olt</tt>: ordered and less than </li>
4002 <li><tt>ole</tt>: ordered and less than or equal</li>
4003 <li><tt>one</tt>: ordered and not equal</li>
4004 <li><tt>ord</tt>: ordered (no nans)</li>
4005 <li><tt>ueq</tt>: unordered or equal</li>
4006 <li><tt>ugt</tt>: unordered or greater than </li>
4007 <li><tt>uge</tt>: unordered or greater than or equal</li>
4008 <li><tt>ult</tt>: unordered or less than </li>
4009 <li><tt>ule</tt>: unordered or less than or equal</li>
4010 <li><tt>une</tt>: unordered or not equal</li>
4011 <li><tt>uno</tt>: unordered (either nans)</li>
4012 <li><tt>true</tt>: no comparison, always returns true</li>
4013</ol>
4014<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4015<a href="#t_floating">floating point</a> typed. They must also be identical
4016types.</p>
4017<h5>Semantics:</h5>
4018<p>The '<tt>vfcmp</tt>' instruction compares <tt>var1</tt> and <tt>var2</tt>
4019according to the condition code given as <tt>cond</tt>. The comparison yields a
4020<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4021an identical number of elements as the values being compared, and each element
4022having identical with to the width of the floating point elements. The most
4023significant bit in each element is 1 if the element-wise comparison evaluates to
4024true, and is 0 otherwise. All other bits of the result are undefined. The
4025condition codes are evaluated identically to the
4026<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.
4027
4028<h5>Example:</h5>
4029<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4030 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4031 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt; <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
Nate Begemand2195702008-05-12 19:01:56 +0000[diff] [blame]4032</pre>
4033</div>
4034
4035<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4036<div class="doc_subsubsection">
4037 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4038</div>
4039
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4040<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4041
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4042<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4043
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4044<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4045<h5>Overview:</h5>
4046<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4047the SSA graph representing the function.</p>
4048<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4049
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4050<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4051field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4052as arguments, with one pair for each predecessor basic block of the
4053current block. Only values of <a href="#t_firstclass">first class</a>
4054type may be used as the value arguments to the PHI node. Only labels
4055may be used as the label arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4056
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4057<p>There must be no non-phi instructions between the start of a basic
4058block and the PHI instructions: i.e. PHI instructions must be first in
4059a basic block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4060
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4061<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4062
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4063<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4064specified by the pair corresponding to the predecessor basic block that executed
4065just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4066
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4067<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4068<pre>
4069Loop: ; Infinite loop that counts from 0 on up...
4070 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4071 %nextindvar = add i32 %indvar, 1
4072 br label %Loop
4073</pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]4074</div>
4075
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4076<!-- _______________________________________________________________________ -->
4077<div class="doc_subsubsection">
4078 <a name="i_select">'<tt>select</tt>' Instruction</a>
4079</div>
4080
4081<div class="doc_text">
4082
4083<h5>Syntax:</h5>
4084
4085<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4086 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4087</pre>
4088
4089<h5>Overview:</h5>
4090
4091<p>
4092The '<tt>select</tt>' instruction is used to choose one value based on a
4093condition, without branching.
4094</p>
4095
4096
4097<h5>Arguments:</h5>
4098
4099<p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4100The '<tt>select</tt>' instruction requires an 'i1' value indicating the
4101condition, and two values of the same <a href="#t_firstclass">first class</a>
4102type. If the val1/val2 are vectors, the entire vectors are selected, not
4103individual elements.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4104</p>
4105
4106<h5>Semantics:</h5>
4107
4108<p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4109If the i1 condition evaluates is 1, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4110value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4111</p>
4112
4113<h5>Example:</h5>
4114
4115<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]4116 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]4117</pre>
4118</div>
4119
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]4120
4121<!-- _______________________________________________________________________ -->
4122<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4123 <a name="i_call">'<tt>call</tt>' Instruction</a>
4124</div>
4125
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4126<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4127
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4128<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4129<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4130 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4131</pre>
4132
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4133<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4134
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4135<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4136
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4137<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4138
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4139<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4140
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4141<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4142 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]4143 <p>The optional "tail" marker indicates whether the callee function accesses
4144 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4145 function call is eligible for tail call optimization. Note that calls may
4146 be marked "tail" even if they do not occur before a <a
4147 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4148 </li>
4149 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]4150 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]4151 convention</a> the call should use. If none is specified, the call defaults
4152 to using C calling conventions.
4153 </li>
4154 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4155 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4156 the type of the return value. Functions that return no value are marked
4157 <tt><a href="#t_void">void</a></tt>.</p>
4158 </li>
4159 <li>
4160 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4161 value being invoked. The argument types must match the types implied by
4162 this signature. This type can be omitted if the function is not varargs
4163 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4164 </li>
4165 <li>
4166 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4167 be invoked. In most cases, this is a direct function invocation, but
4168 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4169 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4170 </li>
4171 <li>
4172 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]4173 function signature argument types. All arguments must be of
4174 <a href="#t_firstclass">first class</a> type. If the function signature
4175 indicates the function accepts a variable number of arguments, the extra
4176 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4177 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]4178</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4179
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4180<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4181
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4182<p>The '<tt>call</tt>' instruction is used to cause control flow to
4183transfer to a specified function, with its incoming arguments bound to
4184the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4185instruction in the called function, control flow continues with the
4186instruction after the function call, and the return value of the
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4187function is bound to the result argument. If the callee returns multiple
4188values then the return values of the function are only accessible through
4189the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4190
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4191<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4192
4193<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]4194 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4195 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4196 %X = tail call i32 @foo() <i>; yields i32</i>
4197 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4198 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4199
4200 %struct.A = type { i32, i8 }
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]4201 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
4202 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
4203 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]4204</pre>
4205
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4206</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4207
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4208<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4209<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4210 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4211</div>
4212
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4213<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4214
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4215<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4216
4217<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4218 &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]4219</pre>
4220
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4221<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4222
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4223<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4224the "variable argument" area of a function call. It is used to implement the
4225<tt>va_arg</tt> macro in C.</p>
4226
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4227<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4228
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4229<p>This instruction takes a <tt>va_list*</tt> value and the type of
4230the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4231increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4232actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4233
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4234<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4235
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4236<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4237type from the specified <tt>va_list</tt> and causes the
4238<tt>va_list</tt> to point to the next argument. For more information,
4239see the variable argument handling <a href="#int_varargs">Intrinsic
4240Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4241
4242<p>It is legal for this instruction to be called in a function which does not
4243take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4244function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4245
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4246<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4247href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4248argument.</p>
4249
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]4250<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]4251
4252<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4253
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4254</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4255
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4256<!-- _______________________________________________________________________ -->
4257<div class="doc_subsubsection">
4258 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
4259</div>
4260
4261<div class="doc_text">
4262
4263<h5>Syntax:</h5>
4264<pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4265 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4266</pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4267
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4268<h5>Overview:</h5>
4269
4270<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4271from a '<tt><a href="#i_call">call</a></tt>'
4272or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
4273results.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4274
4275<h5>Arguments:</h5>
4276
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4277<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
Chris Lattner1a640a62008-04-23 04:06:52 +0000[diff] [blame]4278first argument, or an undef value. The value must have <a
4279href="#t_struct">structure type</a>. The second argument is a constant
4280unsigned index value which must be in range for the number of values returned
4281by the call.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4282
4283<h5>Semantics:</h5>
4284
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4285<p>The '<tt>getresult</tt>' instruction extracts the element identified by
4286'<tt>index</tt>' from the aggregate value.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4287
4288<h5>Example:</h5>
4289
4290<pre>
4291 %struct.A = type { i32, i8 }
4292
4293 %r = call %struct.A @foo()
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]4294 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
4295 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]4296 add i32 %gr, 42
4297 add i8 %gr1, 41
4298</pre>
4299
4300</div>
4301
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4302<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4303<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4304<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4305
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4306<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4307
4308<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4309well known names and semantics and are required to follow certain restrictions.
4310Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4311language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]4312adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4313
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4314<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4315prefix is reserved in LLVM for intrinsic names; thus, function names may not
4316begin with this prefix. Intrinsic functions must always be external functions:
4317you cannot define the body of intrinsic functions. Intrinsic functions may
4318only be used in call or invoke instructions: it is illegal to take the address
4319of an intrinsic function. Additionally, because intrinsic functions are part
4320of the LLVM language, it is required if any are added that they be documented
4321here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4322
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4323<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4324a family of functions that perform the same operation but on different data
4325types. Because LLVM can represent over 8 million different integer types,
4326overloading is used commonly to allow an intrinsic function to operate on any
4327integer type. One or more of the argument types or the result type can be
4328overloaded to accept any integer type. Argument types may also be defined as
4329exactly matching a previous argument's type or the result type. This allows an
4330intrinsic function which accepts multiple arguments, but needs all of them to
4331be of the same type, to only be overloaded with respect to a single argument or
4332the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4333
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4334<p>Overloaded intrinsics will have the names of its overloaded argument types
4335encoded into its function name, each preceded by a period. Only those types
4336which are overloaded result in a name suffix. Arguments whose type is matched
4337against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4338take an integer of any width and returns an integer of exactly the same integer
4339width. This leads to a family of functions such as
4340<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4341Only one type, the return type, is overloaded, and only one type suffix is
4342required. Because the argument's type is matched against the return type, it
4343does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4344
4345<p>To learn how to add an intrinsic function, please see the
4346<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4347</p>
4348
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4349</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4350
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4351<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4352<div class="doc_subsection">
4353 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4354</div>
4355
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4356<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4357
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4358<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4359 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4360intrinsic functions. These functions are related to the similarly
4361named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4362
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4363<p>All of these functions operate on arguments that use a
4364target-specific value type "<tt>va_list</tt>". The LLVM assembly
4365language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4366transformations should be prepared to handle these functions regardless of
4367the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4368
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]4369<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4370instruction and the variable argument handling intrinsic functions are
4371used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4372
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4373<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4374<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4375define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4376 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4377 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4378 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4379 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4380
4381 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4382 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4383
4384 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4385 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4386 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4387 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4388 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4389
4390 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4391 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4392 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4393}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4394
4395declare void @llvm.va_start(i8*)
4396declare void @llvm.va_copy(i8*, i8*)
4397declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4398</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4399</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4400
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4401</div>
4402
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4403<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4404<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4405 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4406</div>
4407
4408
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4409<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4410<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4411<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4412<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4413<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4414<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4415href="#i_va_arg">va_arg</a></tt>.</p>
4416
4417<h5>Arguments:</h5>
4418
4419<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4420
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4421<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4422
4423<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4424macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4425<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4426<tt>va_arg</tt> will produce the first variable argument passed to the function.
4427Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4428last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4429
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4430</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4431
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4432<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4433<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4434 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4435</div>
4436
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4437<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4438<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4439<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4440<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4441
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4442<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4443which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4444or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4445
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4446<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4447
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4448<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]4449
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4450<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4451
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4452<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4453macro available in C. In a target-dependent way, it destroys the
4454<tt>va_list</tt> element to which the argument points. Calls to <a
4455href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4456<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4457<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4458
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4459</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4460
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4461<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4462<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4463 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4464</div>
4465
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4466<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4467
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4468<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4469
4470<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4471 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4472</pre>
4473
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4474<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4475
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4476<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4477from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4478
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4479<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4480
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4481<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]4482The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4483
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4484
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4485<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4486
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4487<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4488macro available in C. In a target-dependent way, it copies the source
4489<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4490intrinsic is necessary because the <tt><a href="#int_va_start">
4491llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4492example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4493
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4494</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4495
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4496<!-- ======================================================================= -->
4497<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4498 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4499</div>
4500
4501<div class="doc_text">
4502
4503<p>
4504LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4505Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4506These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4507stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4508href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4509Front-ends for type-safe garbage collected languages should generate these
4510intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4511href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4512</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4513
4514<p>The garbage collection intrinsics only operate on objects in the generic
4515 address space (address space zero).</p>
4516
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4517</div>
4518
4519<!-- _______________________________________________________________________ -->
4520<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4521 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4522</div>
4523
4524<div class="doc_text">
4525
4526<h5>Syntax:</h5>
4527
4528<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4529 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4530</pre>
4531
4532<h5>Overview:</h5>
4533
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4534<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4535the code generator, and allows some metadata to be associated with it.</p>
4536
4537<h5>Arguments:</h5>
4538
4539<p>The first argument specifies the address of a stack object that contains the
4540root pointer. The second pointer (which must be either a constant or a global
4541value address) contains the meta-data to be associated with the root.</p>
4542
4543<h5>Semantics:</h5>
4544
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]4545<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4546location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4547the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4548intrinsic may only be used in a function which <a href="#gc">specifies a GC
4549algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4550
4551</div>
4552
4553
4554<!-- _______________________________________________________________________ -->
4555<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4556 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4557</div>
4558
4559<div class="doc_text">
4560
4561<h5>Syntax:</h5>
4562
4563<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4564 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4565</pre>
4566
4567<h5>Overview:</h5>
4568
4569<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4570locations, allowing garbage collector implementations that require read
4571barriers.</p>
4572
4573<h5>Arguments:</h5>
4574
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4575<p>The second argument is the address to read from, which should be an address
4576allocated from the garbage collector. The first object is a pointer to the
4577start of the referenced object, if needed by the language runtime (otherwise
4578null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4579
4580<h5>Semantics:</h5>
4581
4582<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4583instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4584garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4585may only be used in a function which <a href="#gc">specifies a GC
4586algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4587
4588</div>
4589
4590
4591<!-- _______________________________________________________________________ -->
4592<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4593 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4594</div>
4595
4596<div class="doc_text">
4597
4598<h5>Syntax:</h5>
4599
4600<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4601 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4602</pre>
4603
4604<h5>Overview:</h5>
4605
4606<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4607locations, allowing garbage collector implementations that require write
4608barriers (such as generational or reference counting collectors).</p>
4609
4610<h5>Arguments:</h5>
4611
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4612<p>The first argument is the reference to store, the second is the start of the
4613object to store it to, and the third is the address of the field of Obj to
4614store to. If the runtime does not require a pointer to the object, Obj may be
4615null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4616
4617<h5>Semantics:</h5>
4618
4619<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4620instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4621garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4622may only be used in a function which <a href="#gc">specifies a GC
4623algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4624
4625</div>
4626
4627
4628
4629<!-- ======================================================================= -->
4630<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4631 <a name="int_codegen">Code Generator Intrinsics</a>
4632</div>
4633
4634<div class="doc_text">
4635<p>
4636These intrinsics are provided by LLVM to expose special features that may only
4637be implemented with code generator support.
4638</p>
4639
4640</div>
4641
4642<!-- _______________________________________________________________________ -->
4643<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4644 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4645</div>
4646
4647<div class="doc_text">
4648
4649<h5>Syntax:</h5>
4650<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4651 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4652</pre>
4653
4654<h5>Overview:</h5>
4655
4656<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4657The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4658target-specific value indicating the return address of the current function
4659or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4660</p>
4661
4662<h5>Arguments:</h5>
4663
4664<p>
4665The argument to this intrinsic indicates which function to return the address
4666for. Zero indicates the calling function, one indicates its caller, etc. The
4667argument is <b>required</b> to be a constant integer value.
4668</p>
4669
4670<h5>Semantics:</h5>
4671
4672<p>
4673The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4674the return address of the specified call frame, or zero if it cannot be
4675identified. The value returned by this intrinsic is likely to be incorrect or 0
4676for arguments other than zero, so it should only be used for debugging purposes.
4677</p>
4678
4679<p>
4680Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4681aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4682source-language caller.
4683</p>
4684</div>
4685
4686
4687<!-- _______________________________________________________________________ -->
4688<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4689 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4690</div>
4691
4692<div class="doc_text">
4693
4694<h5>Syntax:</h5>
4695<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4696 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4697</pre>
4698
4699<h5>Overview:</h5>
4700
4701<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4702The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4703target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4704</p>
4705
4706<h5>Arguments:</h5>
4707
4708<p>
4709The argument to this intrinsic indicates which function to return the frame
4710pointer for. Zero indicates the calling function, one indicates its caller,
4711etc. The argument is <b>required</b> to be a constant integer value.
4712</p>
4713
4714<h5>Semantics:</h5>
4715
4716<p>
4717The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4718the frame address of the specified call frame, or zero if it cannot be
4719identified. The value returned by this intrinsic is likely to be incorrect or 0
4720for arguments other than zero, so it should only be used for debugging purposes.
4721</p>
4722
4723<p>
4724Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4725aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4726source-language caller.
4727</p>
4728</div>
4729
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4730<!-- _______________________________________________________________________ -->
4731<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4732 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4733</div>
4734
4735<div class="doc_text">
4736
4737<h5>Syntax:</h5>
4738<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4739 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4740</pre>
4741
4742<h5>Overview:</h5>
4743
4744<p>
4745The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4746the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4747<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4748features like scoped automatic variable sized arrays in C99.
4749</p>
4750
4751<h5>Semantics:</h5>
4752
4753<p>
4754This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4755href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4756<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4757<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4758state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4759practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4760that were allocated after the <tt>llvm.stacksave</tt> was executed.
4761</p>
4762
4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4767 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4768</div>
4769
4770<div class="doc_text">
4771
4772<h5>Syntax:</h5>
4773<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4774 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4775</pre>
4776
4777<h5>Overview:</h5>
4778
4779<p>
4780The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4781the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4782href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4783useful for implementing language features like scoped automatic variable sized
4784arrays in C99.
4785</p>
4786
4787<h5>Semantics:</h5>
4788
4789<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4790See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4791</p>
4792
4793</div>
4794
4795
4796<!-- _______________________________________________________________________ -->
4797<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4798 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4799</div>
4800
4801<div class="doc_text">
4802
4803<h5>Syntax:</h5>
4804<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4805 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]4806</pre>
4807
4808<h5>Overview:</h5>
4809
4810
4811<p>
4812The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4813a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4814no
4815effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4816characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4817</p>
4818
4819<h5>Arguments:</h5>
4820
4821<p>
4822<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4823determining if the fetch should be for a read (0) or write (1), and
4824<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4825locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4826<tt>locality</tt> arguments must be constant integers.
4827</p>
4828
4829<h5>Semantics:</h5>
4830
4831<p>
4832This intrinsic does not modify the behavior of the program. In particular,
4833prefetches cannot trap and do not produce a value. On targets that support this
4834intrinsic, the prefetch can provide hints to the processor cache for better
4835performance.
4836</p>
4837
4838</div>
4839
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4840<!-- _______________________________________________________________________ -->
4841<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4842 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4843</div>
4844
4845<div class="doc_text">
4846
4847<h5>Syntax:</h5>
4848<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4849 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4850</pre>
4851
4852<h5>Overview:</h5>
4853
4854
4855<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4856The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4857(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4858code to simulators and other tools. The method is target specific, but it is
4859expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4860The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4861after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4862optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4863correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4864</p>
4865
4866<h5>Arguments:</h5>
4867
4868<p>
4869<tt>id</tt> is a numerical id identifying the marker.
4870</p>
4871
4872<h5>Semantics:</h5>
4873
4874<p>
4875This intrinsic does not modify the behavior of the program. Backends that do not
4876support this intrinisic may ignore it.
4877</p>
4878
4879</div>
4880
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4883 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4884</div>
4885
4886<div class="doc_text">
4887
4888<h5>Syntax:</h5>
4889<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4890 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4891</pre>
4892
4893<h5>Overview:</h5>
4894
4895
4896<p>
4897The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4898counter register (or similar low latency, high accuracy clocks) on those targets
4899that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4900As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4901should only be used for small timings.
4902</p>
4903
4904<h5>Semantics:</h5>
4905
4906<p>
4907When directly supported, reading the cycle counter should not modify any memory.
4908Implementations are allowed to either return a application specific value or a
4909system wide value. On backends without support, this is lowered to a constant 0.
4910</p>
4911
4912</div>
4913
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4914<!-- ======================================================================= -->
4915<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4916 <a name="int_libc">Standard C Library Intrinsics</a>
4917</div>
4918
4919<div class="doc_text">
4920<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4921LLVM provides intrinsics for a few important standard C library functions.
4922These intrinsics allow source-language front-ends to pass information about the
4923alignment of the pointer arguments to the code generator, providing opportunity
4924for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4925</p>
4926
4927</div>
4928
4929<!-- _______________________________________________________________________ -->
4930<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4931 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4932</div>
4933
4934<div class="doc_text">
4935
4936<h5>Syntax:</h5>
4937<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4938 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4939 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4940 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4941 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4942</pre>
4943
4944<h5>Overview:</h5>
4945
4946<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4947The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4948location to the destination location.
4949</p>
4950
4951<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4952Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4953intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4954</p>
4955
4956<h5>Arguments:</h5>
4957
4958<p>
4959The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4960the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4961specifying the number of bytes to copy, and the fourth argument is the alignment
4962of the source and destination locations.
4963</p>
4964
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4965<p>
4966If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4967the caller guarantees that both the source and destination pointers are aligned
4968to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4969</p>
4970
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4971<h5>Semantics:</h5>
4972
4973<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4974The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4975location to the destination location, which are not allowed to overlap. It
4976copies "len" bytes of memory over. If the argument is known to be aligned to
4977some boundary, this can be specified as the fourth argument, otherwise it should
4978be set to 0 or 1.
4979</p>
4980</div>
4981
4982
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4983<!-- _______________________________________________________________________ -->
4984<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4985 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4986</div>
4987
4988<div class="doc_text">
4989
4990<h5>Syntax:</h5>
4991<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4992 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4993 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4994 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4995 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4996</pre>
4997
4998<h5>Overview:</h5>
4999
5000<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5001The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5002location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]5003'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5004</p>
5005
5006<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5007Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5008intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5009</p>
5010
5011<h5>Arguments:</h5>
5012
5013<p>
5014The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5015the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5016specifying the number of bytes to copy, and the fourth argument is the alignment
5017of the source and destination locations.
5018</p>
5019
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5020<p>
5021If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]5022the caller guarantees that the source and destination pointers are aligned to
5023that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]5024</p>
5025
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5026<h5>Semantics:</h5>
5027
5028<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5029The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]5030location to the destination location, which may overlap. It
5031copies "len" bytes of memory over. If the argument is known to be aligned to
5032some boundary, this can be specified as the fourth argument, otherwise it should
5033be set to 0 or 1.
5034</p>
5035</div>
5036
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5037
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5038<!-- _______________________________________________________________________ -->
5039<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5040 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5041</div>
5042
5043<div class="doc_text">
5044
5045<h5>Syntax:</h5>
5046<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5047 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5048 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5049 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5050 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5051</pre>
5052
5053<h5>Overview:</h5>
5054
5055<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5056The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5057byte value.
5058</p>
5059
5060<p>
5061Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5062does not return a value, and takes an extra alignment argument.
5063</p>
5064
5065<h5>Arguments:</h5>
5066
5067<p>
5068The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5069byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5070argument specifying the number of bytes to fill, and the fourth argument is the
5071known alignment of destination location.
5072</p>
5073
5074<p>
5075If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]5076the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5077</p>
5078
5079<h5>Semantics:</h5>
5080
5081<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]5082The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5083the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]5084destination location. If the argument is known to be aligned to some boundary,
5085this can be specified as the fourth argument, otherwise it should be set to 0 or
50861.
5087</p>
5088</div>
5089
5090
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5091<!-- _______________________________________________________________________ -->
5092<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5093 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5094</div>
5095
5096<div class="doc_text">
5097
5098<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5099<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5100floating point or vector of floating point type. Not all targets support all
5101types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5102<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5103 declare float @llvm.sqrt.f32(float %Val)
5104 declare double @llvm.sqrt.f64(double %Val)
5105 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5106 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5107 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5108</pre>
5109
5110<h5>Overview:</h5>
5111
5112<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5113The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5114returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5115<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +0000[diff] [blame]5116negative numbers other than -0.0 (which allows for better optimization, because
5117there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5118defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5119</p>
5120
5121<h5>Arguments:</h5>
5122
5123<p>
5124The argument and return value are floating point numbers of the same type.
5125</p>
5126
5127<h5>Semantics:</h5>
5128
5129<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]5130This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]5131floating point number.
5132</p>
5133</div>
5134
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5135<!-- _______________________________________________________________________ -->
5136<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5137 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5138</div>
5139
5140<div class="doc_text">
5141
5142<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5143<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5144floating point or vector of floating point type. Not all targets support all
5145types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5146<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]5147 declare float @llvm.powi.f32(float %Val, i32 %power)
5148 declare double @llvm.powi.f64(double %Val, i32 %power)
5149 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5150 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5151 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5152</pre>
5153
5154<h5>Overview:</h5>
5155
5156<p>
5157The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5158specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5159multiplications is not defined. When a vector of floating point type is
5160used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5161</p>
5162
5163<h5>Arguments:</h5>
5164
5165<p>
5166The second argument is an integer power, and the first is a value to raise to
5167that power.
5168</p>
5169
5170<h5>Semantics:</h5>
5171
5172<p>
5173This function returns the first value raised to the second power with an
5174unspecified sequence of rounding operations.</p>
5175</div>
5176
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5177<!-- _______________________________________________________________________ -->
5178<div class="doc_subsubsection">
5179 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5180</div>
5181
5182<div class="doc_text">
5183
5184<h5>Syntax:</h5>
5185<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5186floating point or vector of floating point type. Not all targets support all
5187types however.
5188<pre>
5189 declare float @llvm.sin.f32(float %Val)
5190 declare double @llvm.sin.f64(double %Val)
5191 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5192 declare fp128 @llvm.sin.f128(fp128 %Val)
5193 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5194</pre>
5195
5196<h5>Overview:</h5>
5197
5198<p>
5199The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5200</p>
5201
5202<h5>Arguments:</h5>
5203
5204<p>
5205The argument and return value are floating point numbers of the same type.
5206</p>
5207
5208<h5>Semantics:</h5>
5209
5210<p>
5211This function returns the sine of the specified operand, returning the
5212same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5213conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5214</div>
5215
5216<!-- _______________________________________________________________________ -->
5217<div class="doc_subsubsection">
5218 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5219</div>
5220
5221<div class="doc_text">
5222
5223<h5>Syntax:</h5>
5224<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5225floating point or vector of floating point type. Not all targets support all
5226types however.
5227<pre>
5228 declare float @llvm.cos.f32(float %Val)
5229 declare double @llvm.cos.f64(double %Val)
5230 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5231 declare fp128 @llvm.cos.f128(fp128 %Val)
5232 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5233</pre>
5234
5235<h5>Overview:</h5>
5236
5237<p>
5238The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5239</p>
5240
5241<h5>Arguments:</h5>
5242
5243<p>
5244The argument and return value are floating point numbers of the same type.
5245</p>
5246
5247<h5>Semantics:</h5>
5248
5249<p>
5250This function returns the cosine of the specified operand, returning the
5251same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5252conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5253</div>
5254
5255<!-- _______________________________________________________________________ -->
5256<div class="doc_subsubsection">
5257 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5258</div>
5259
5260<div class="doc_text">
5261
5262<h5>Syntax:</h5>
5263<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5264floating point or vector of floating point type. Not all targets support all
5265types however.
5266<pre>
5267 declare float @llvm.pow.f32(float %Val, float %Power)
5268 declare double @llvm.pow.f64(double %Val, double %Power)
5269 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5270 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5271 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5272</pre>
5273
5274<h5>Overview:</h5>
5275
5276<p>
5277The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5278specified (positive or negative) power.
5279</p>
5280
5281<h5>Arguments:</h5>
5282
5283<p>
5284The second argument is a floating point power, and the first is a value to
5285raise to that power.
5286</p>
5287
5288<h5>Semantics:</h5>
5289
5290<p>
5291This function returns the first value raised to the second power,
5292returning the
5293same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]5294conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]5295</div>
5296
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]5297
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5298<!-- ======================================================================= -->
5299<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5300 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5301</div>
5302
5303<div class="doc_text">
5304<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5305LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5306These allow efficient code generation for some algorithms.
5307</p>
5308
5309</div>
5310
5311<!-- _______________________________________________________________________ -->
5312<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5313 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5314</div>
5315
5316<div class="doc_text">
5317
5318<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5319<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5320type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5321<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5322 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5323 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5324 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5325</pre>
5326
5327<h5>Overview:</h5>
5328
5329<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]5330The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5331values with an even number of bytes (positive multiple of 16 bits). These are
5332useful for performing operations on data that is not in the target's native
5333byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5334</p>
5335
5336<h5>Semantics:</h5>
5337
5338<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5339The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5340and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5341intrinsic returns an i32 value that has the four bytes of the input i32
5342swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5343i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5344<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5345additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]5346</p>
5347
5348</div>
5349
5350<!-- _______________________________________________________________________ -->
5351<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5352 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5353</div>
5354
5355<div class="doc_text">
5356
5357<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5358<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5359width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5360<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5361 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5362 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5363 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5364 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5365 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5366</pre>
5367
5368<h5>Overview:</h5>
5369
5370<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]5371The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5372value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5373</p>
5374
5375<h5>Arguments:</h5>
5376
5377<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5378The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5379integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5380</p>
5381
5382<h5>Semantics:</h5>
5383
5384<p>
5385The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5386</p>
5387</div>
5388
5389<!-- _______________________________________________________________________ -->
5390<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5391 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5392</div>
5393
5394<div class="doc_text">
5395
5396<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5397<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5398integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5399<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5400 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5401 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5402 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5403 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5404 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5405</pre>
5406
5407<h5>Overview:</h5>
5408
5409<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5410The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5411leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5412</p>
5413
5414<h5>Arguments:</h5>
5415
5416<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5417The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5418integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5419</p>
5420
5421<h5>Semantics:</h5>
5422
5423<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5424The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5425in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5426of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5427</p>
5428</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5429
5430
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5431
5432<!-- _______________________________________________________________________ -->
5433<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5434 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5435</div>
5436
5437<div class="doc_text">
5438
5439<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5440<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5441integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5442<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5443 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5444 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5445 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5446 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5447 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5448</pre>
5449
5450<h5>Overview:</h5>
5451
5452<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5453The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5454trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5455</p>
5456
5457<h5>Arguments:</h5>
5458
5459<p>
5460The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5461integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5462</p>
5463
5464<h5>Semantics:</h5>
5465
5466<p>
5467The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5468in a variable. If the src == 0 then the result is the size in bits of the type
5469of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5470</p>
5471</div>
5472
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5473<!-- _______________________________________________________________________ -->
5474<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5475 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5476</div>
5477
5478<div class="doc_text">
5479
5480<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5481<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5482on any integer bit width.
5483<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5484 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5485 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5486</pre>
5487
5488<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5489<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5490range of bits from an integer value and returns them in the same bit width as
5491the original value.</p>
5492
5493<h5>Arguments:</h5>
5494<p>The first argument, <tt>%val</tt> and the result may be integer types of
5495any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5496arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5497
5498<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5499<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5500of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5501<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5502operates in forward mode.</p>
5503<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5504right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5505only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5506<ol>
5507 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5508 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5509 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5510 to determine the number of bits to retain.</li>
5511 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5512 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5513</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5514<p>In reverse mode, a similar computation is made except that the bits are
5515returned in the reverse order. So, for example, if <tt>X</tt> has the value
5516<tt>i16 0x0ACF (101011001111)</tt> and we apply
5517<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5518<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5519</div>
5520
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5521<div class="doc_subsubsection">
5522 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5523</div>
5524
5525<div class="doc_text">
5526
5527<h5>Syntax:</h5>
5528<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5529on any integer bit width.
5530<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5531 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5532 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5533</pre>
5534
5535<h5>Overview:</h5>
5536<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5537of bits in an integer value with another integer value. It returns the integer
5538with the replaced bits.</p>
5539
5540<h5>Arguments:</h5>
5541<p>The first argument, <tt>%val</tt> and the result may be integer types of
5542any bit width but they must have the same bit width. <tt>%val</tt> is the value
5543whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5544integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5545type since they specify only a bit index.</p>
5546
5547<h5>Semantics:</h5>
5548<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5549of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5550<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5551operates in forward mode.</p>
5552<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5553truncating it down to the size of the replacement area or zero extending it
5554up to that size.</p>
5555<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5556are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5557in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5558to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5559<p>In reverse mode, a similar computation is made except that the bits are
5560reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5561<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5562<h5>Examples:</h5>
5563<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5564 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5565 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5566 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5567 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5568 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5569</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5570</div>
5571
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5572<!-- ======================================================================= -->
5573<div class="doc_subsection">
5574 <a name="int_debugger">Debugger Intrinsics</a>
5575</div>
5576
5577<div class="doc_text">
5578<p>
5579The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5580are described in the <a
5581href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5582Debugging</a> document.
5583</p>
5584</div>
5585
5586
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5587<!-- ======================================================================= -->
5588<div class="doc_subsection">
5589 <a name="int_eh">Exception Handling Intrinsics</a>
5590</div>
5591
5592<div class="doc_text">
5593<p> The LLVM exception handling intrinsics (which all start with
5594<tt>llvm.eh.</tt> prefix), are described in the <a
5595href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5596Handling</a> document. </p>
5597</div>
5598
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5599<!-- ======================================================================= -->
5600<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5601 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5602</div>
5603
5604<div class="doc_text">
5605<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5606 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5607 the <tt>nest</tt> attribute, from a function. The result is a callable
5608 function pointer lacking the nest parameter - the caller does not need
5609 to provide a value for it. Instead, the value to use is stored in
5610 advance in a "trampoline", a block of memory usually allocated
5611 on the stack, which also contains code to splice the nest value into the
5612 argument list. This is used to implement the GCC nested function address
5613 extension.
5614</p>
5615<p>
5616 For example, if the function is
5617 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5618 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5619<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5620 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5621 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5622 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5623 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5624</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5625 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5626 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5627</div>
5628
5629<!-- _______________________________________________________________________ -->
5630<div class="doc_subsubsection">
5631 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5632</div>
5633<div class="doc_text">
5634<h5>Syntax:</h5>
5635<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5636declare 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]5637</pre>
5638<h5>Overview:</h5>
5639<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5640 This fills the memory pointed to by <tt>tramp</tt> with code
5641 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5642</p>
5643<h5>Arguments:</h5>
5644<p>
5645 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5646 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5647 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5648 intrinsic. Note that the size and the alignment are target-specific - LLVM
5649 currently provides no portable way of determining them, so a front-end that
5650 generates this intrinsic needs to have some target-specific knowledge.
5651 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5652</p>
5653<h5>Semantics:</h5>
5654<p>
5655 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5656 dependent code, turning it into a function. A pointer to this function is
5657 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5658 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5659 before being called. The new function's signature is the same as that of
5660 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5661 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5662 of pointer type. Calling the new function is equivalent to calling
5663 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5664 missing <tt>nest</tt> argument. If, after calling
5665 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5666 modified, then the effect of any later call to the returned function pointer is
5667 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5668</p>
5669</div>
5670
5671<!-- ======================================================================= -->
5672<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5673 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5674</div>
5675
5676<div class="doc_text">
5677<p>
5678 These intrinsic functions expand the "universal IR" of LLVM to represent
5679 hardware constructs for atomic operations and memory synchronization. This
5680 provides an interface to the hardware, not an interface to the programmer. It
5681 is aimed at a low enough level to allow any programming models or APIs which
5682 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5683 hardware behavior. Just as hardware provides a "universal IR" for source
5684 languages, it also provides a starting point for developing a "universal"
5685 atomic operation and synchronization IR.
5686</p>
5687<p>
5688 These do <em>not</em> form an API such as high-level threading libraries,
5689 software transaction memory systems, atomic primitives, and intrinsic
5690 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5691 application libraries. The hardware interface provided by LLVM should allow
5692 a clean implementation of all of these APIs and parallel programming models.
5693 No one model or paradigm should be selected above others unless the hardware
5694 itself ubiquitously does so.
5695
5696</p>
5697</div>
5698
5699<!-- _______________________________________________________________________ -->
5700<div class="doc_subsubsection">
5701 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5702</div>
5703<div class="doc_text">
5704<h5>Syntax:</h5>
5705<pre>
5706declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5707i1 &lt;device&gt; )
5708
5709</pre>
5710<h5>Overview:</h5>
5711<p>
5712 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5713 specific pairs of memory access types.
5714</p>
5715<h5>Arguments:</h5>
5716<p>
5717 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5718 The first four arguments enables a specific barrier as listed below. The fith
5719 argument specifies that the barrier applies to io or device or uncached memory.
5720
5721</p>
5722 <ul>
5723 <li><tt>ll</tt>: load-load barrier</li>
5724 <li><tt>ls</tt>: load-store barrier</li>
5725 <li><tt>sl</tt>: store-load barrier</li>
5726 <li><tt>ss</tt>: store-store barrier</li>
5727 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5728 </ul>
5729<h5>Semantics:</h5>
5730<p>
5731 This intrinsic causes the system to enforce some ordering constraints upon
5732 the loads and stores of the program. This barrier does not indicate
5733 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5734 which they occur. For any of the specified pairs of load and store operations
5735 (f.ex. load-load, or store-load), all of the first operations preceding the
5736 barrier will complete before any of the second operations succeeding the
5737 barrier begin. Specifically the semantics for each pairing is as follows:
5738</p>
5739 <ul>
5740 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5741 after the barrier begins.</li>
5742
5743 <li><tt>ls</tt>: All loads before the barrier must complete before any
5744 store after the barrier begins.</li>
5745 <li><tt>ss</tt>: All stores before the barrier must complete before any
5746 store after the barrier begins.</li>
5747 <li><tt>sl</tt>: All stores before the barrier must complete before any
5748 load after the barrier begins.</li>
5749 </ul>
5750<p>
5751 These semantics are applied with a logical "and" behavior when more than one
5752 is enabled in a single memory barrier intrinsic.
5753</p>
5754<p>
5755 Backends may implement stronger barriers than those requested when they do not
5756 support as fine grained a barrier as requested. Some architectures do not
5757 need all types of barriers and on such architectures, these become noops.
5758</p>
5759<h5>Example:</h5>
5760<pre>
5761%ptr = malloc i32
5762 store i32 4, %ptr
5763
5764%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5765 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5766 <i>; guarantee the above finishes</i>
5767 store i32 8, %ptr <i>; before this begins</i>
5768</pre>
5769</div>
5770
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]5771<!-- _______________________________________________________________________ -->
5772<div class="doc_subsubsection">
5773 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5774</div>
5775<div class="doc_text">
5776<h5>Syntax:</h5>
5777<p>
5778 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5779 integer bit width. Not all targets support all bit widths however.</p>
5780
5781<pre>
5782declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5783declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5784declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5785declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5786
5787</pre>
5788<h5>Overview:</h5>
5789<p>
5790 This loads a value in memory and compares it to a given value. If they are
5791 equal, it stores a new value into the memory.
5792</p>
5793<h5>Arguments:</h5>
5794<p>
5795 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5796 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5797 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5798 this integer type. While any bit width integer may be used, targets may only
5799 lower representations they support in hardware.
5800
5801</p>
5802<h5>Semantics:</h5>
5803<p>
5804 This entire intrinsic must be executed atomically. It first loads the value
5805 in memory pointed to by <tt>ptr</tt> and compares it with the value
5806 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5807 loaded value is yielded in all cases. This provides the equivalent of an
5808 atomic compare-and-swap operation within the SSA framework.
5809</p>
5810<h5>Examples:</h5>
5811
5812<pre>
5813%ptr = malloc i32
5814 store i32 4, %ptr
5815
5816%val1 = add i32 4, 4
5817%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5818 <i>; yields {i32}:result1 = 4</i>
5819%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5820%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5821
5822%val2 = add i32 1, 1
5823%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5824 <i>; yields {i32}:result2 = 8</i>
5825%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5826
5827%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5828</pre>
5829</div>
5830
5831<!-- _______________________________________________________________________ -->
5832<div class="doc_subsubsection">
5833 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5834</div>
5835<div class="doc_text">
5836<h5>Syntax:</h5>
5837
5838<p>
5839 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5840 integer bit width. Not all targets support all bit widths however.</p>
5841<pre>
5842declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5843declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5844declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5845declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5846
5847</pre>
5848<h5>Overview:</h5>
5849<p>
5850 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5851 the value from memory. It then stores the value in <tt>val</tt> in the memory
5852 at <tt>ptr</tt>.
5853</p>
5854<h5>Arguments:</h5>
5855
5856<p>
5857 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5858 <tt>val</tt> argument and the result must be integers of the same bit width.
5859 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5860 integer type. The targets may only lower integer representations they
5861 support.
5862</p>
5863<h5>Semantics:</h5>
5864<p>
5865 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5866 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5867 equivalent of an atomic swap operation within the SSA framework.
5868
5869</p>
5870<h5>Examples:</h5>
5871<pre>
5872%ptr = malloc i32
5873 store i32 4, %ptr
5874
5875%val1 = add i32 4, 4
5876%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5877 <i>; yields {i32}:result1 = 4</i>
5878%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5879%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5880
5881%val2 = add i32 1, 1
5882%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5883 <i>; yields {i32}:result2 = 8</i>
5884
5885%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5886%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5887</pre>
5888</div>
5889
5890<!-- _______________________________________________________________________ -->
5891<div class="doc_subsubsection">
5892 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5893
5894</div>
5895<div class="doc_text">
5896<h5>Syntax:</h5>
5897<p>
5898 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5899 integer bit width. Not all targets support all bit widths however.</p>
5900<pre>
5901declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5902declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5903declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5904declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5905
5906</pre>
5907<h5>Overview:</h5>
5908<p>
5909 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5910 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5911</p>
5912<h5>Arguments:</h5>
5913<p>
5914
5915 The intrinsic takes two arguments, the first a pointer to an integer value
5916 and the second an integer value. The result is also an integer value. These
5917 integer types can have any bit width, but they must all have the same bit
5918 width. The targets may only lower integer representations they support.
5919</p>
5920<h5>Semantics:</h5>
5921<p>
5922 This intrinsic does a series of operations atomically. It first loads the
5923 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5924 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5925</p>
5926
5927<h5>Examples:</h5>
5928<pre>
5929%ptr = malloc i32
5930 store i32 4, %ptr
5931%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5932 <i>; yields {i32}:result1 = 4</i>
5933%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5934 <i>; yields {i32}:result2 = 8</i>
5935%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5936 <i>; yields {i32}:result3 = 10</i>
5937%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5938</pre>
5939</div>
5940
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5941
5942<!-- ======================================================================= -->
5943<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5944 <a name="int_general">General Intrinsics</a>
5945</div>
5946
5947<div class="doc_text">
5948<p> This class of intrinsics is designed to be generic and has
5949no specific purpose. </p>
5950</div>
5951
5952<!-- _______________________________________________________________________ -->
5953<div class="doc_subsubsection">
5954 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5955</div>
5956
5957<div class="doc_text">
5958
5959<h5>Syntax:</h5>
5960<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5961 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]5962</pre>
5963
5964<h5>Overview:</h5>
5965
5966<p>
5967The '<tt>llvm.var.annotation</tt>' intrinsic
5968</p>
5969
5970<h5>Arguments:</h5>
5971
5972<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5973The first argument is a pointer to a value, the second is a pointer to a
5974global string, the third is a pointer to a global string which is the source
5975file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5976</p>
5977
5978<h5>Semantics:</h5>
5979
5980<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5981This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5982This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5983annotations. These have no other defined use, they are ignored by code
5984generation and optimization.
5985</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5986</div>
5987
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5990 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5991</div>
5992
5993<div class="doc_text">
5994
5995<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5996<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5997any integer bit width.
5998</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5999<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]6000 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6001 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6002 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6003 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6004 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]6005</pre>
6006
6007<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6008
6009<p>
6010The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6011</p>
6012
6013<h5>Arguments:</h5>
6014
6015<p>
6016The first argument is an integer value (result of some expression),
6017the second is a pointer to a global string, the third is a pointer to a global
6018string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]6019It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]6020</p>
6021
6022<h5>Semantics:</h5>
6023
6024<p>
6025This intrinsic allows annotations to be put on arbitrary expressions
6026with arbitrary strings. This can be useful for special purpose optimizations
6027that want to look for these annotations. These have no other defined use, they
6028are ignored by code generation and optimization.
6029</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]6030
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]6031<!-- _______________________________________________________________________ -->
6032<div class="doc_subsubsection">
6033 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6034</div>
6035
6036<div class="doc_text">
6037
6038<h5>Syntax:</h5>
6039<pre>
6040 declare void @llvm.trap()
6041</pre>
6042
6043<h5>Overview:</h5>
6044
6045<p>
6046The '<tt>llvm.trap</tt>' intrinsic
6047</p>
6048
6049<h5>Arguments:</h5>
6050
6051<p>
6052None
6053</p>
6054
6055<h5>Semantics:</h5>
6056
6057<p>
6058This intrinsics is lowered to the target dependent trap instruction. If the
6059target does not have a trap instruction, this intrinsic will be lowered to the
6060call of the abort() function.
6061</p>
6062</div>
6063
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6064<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6065<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6066<address>
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6068 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6069 <a href="http://validator.w3.org/check/referer"><img
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Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6071
6072 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]6073 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]6074 Last modified: $Date$
6075</address>
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