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gerrit-public.fairphone.software / toolchain / llvm-project / 74d154ce573e75fdf7bbfd336fc9621c09633252 / . / 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.">
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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>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]114 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]115 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]116 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
117 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
118 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]119 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
120 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
121 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]122 </ol>
123 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]124 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]125 <ol>
126 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
127 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
128 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
129 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
130 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]131 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
132 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
133 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
134 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]135 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
136 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]137 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]138 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#otherops">Other Operations</a>
140 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]141 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
142 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]144 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]146 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]147 <li><a href="#i_getresult">'<tt>getresult</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]148 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]149 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]150 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]151 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]152 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]153 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]154 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
155 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]156 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
157 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
158 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]159 </ol>
160 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]161 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
162 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]163 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
164 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
165 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]166 </ol>
167 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]168 <li><a href="#int_codegen">Code Generator Intrinsics</a>
169 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]170 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
171 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
172 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
173 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
174 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
175 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
176 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]177 </ol>
178 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]179 <li><a href="#int_libc">Standard C Library Intrinsics</a>
180 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]181 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
183 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
184 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
185 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]186 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
187 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
188 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]189 </ol>
190 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]191 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]192 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]193 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]194 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
195 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
196 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]197 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
198 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]199 </ol>
200 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]201 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]202 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]203 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]204 <ol>
205 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]206 </ol>
207 </li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]208 <li><a href="#int_atomics">Atomic intrinsics</a>
209 <ol>
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]210 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
211 <li><a href="#int_atomic_lcs"><tt>llvm.atomic.lcs</tt></a></li>
212 <li><a href="#int_atomic_las"><tt>llvm.atomic.las</tt></a></li>
213 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]214 </ol>
215 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]216 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]217 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]218 <li><a href="#int_var_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]219 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]220 <li><a href="#int_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]221 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]222 <li><a href="#int_trap">
223 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]224 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]225 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]226 </ol>
227 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]228</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229
230<div class="doc_author">
231 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
232 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]233</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]235<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]236<div class="doc_section"> <a name="abstract">Abstract </a></div>
237<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]239<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]240<p>This document is a reference manual for the LLVM assembly language.
241LLVM is an SSA based representation that provides type safety,
242low-level operations, flexibility, and the capability of representing
243'all' high-level languages cleanly. It is the common code
244representation used throughout all phases of the LLVM compilation
245strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]246</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]247
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]248<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]249<div class="doc_section"> <a name="introduction">Introduction</a> </div>
250<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]251
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]252<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]253
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]254<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]255different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]256representation (suitable for fast loading by a Just-In-Time compiler),
257and as a human readable assembly language representation. This allows
258LLVM to provide a powerful intermediate representation for efficient
259compiler transformations and analysis, while providing a natural means
260to debug and visualize the transformations. The three different forms
261of LLVM are all equivalent. This document describes the human readable
262representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]263
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]264<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]265while being expressive, typed, and extensible at the same time. It
266aims to be a "universal IR" of sorts, by being at a low enough level
267that high-level ideas may be cleanly mapped to it (similar to how
268microprocessors are "universal IR's", allowing many source languages to
269be mapped to them). By providing type information, LLVM can be used as
270the target of optimizations: for example, through pointer analysis, it
271can be proven that a C automatic variable is never accessed outside of
272the current function... allowing it to be promoted to a simple SSA
273value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]274
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]275</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]276
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]277<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]278<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]279
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]280<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]281
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]282<p>It is important to note that this document describes 'well formed'
283LLVM assembly language. There is a difference between what the parser
284accepts and what is considered 'well formed'. For example, the
285following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]286
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]287<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]288<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]289%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]290</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]291</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]293<p>...because the definition of <tt>%x</tt> does not dominate all of
294its uses. The LLVM infrastructure provides a verification pass that may
295be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]296automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]297the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]298by the verifier pass indicate bugs in transformation passes or input to
299the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]300</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]301
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]302<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]303
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]304<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]305<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]306<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]307
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]308<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]309
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]310 <p>LLVM identifiers come in two basic types: global and local. Global
311 identifiers (functions, global variables) begin with the @ character. Local
312 identifiers (register names, types) begin with the % character. Additionally,
313 there are three different formats for identifiers, for different purposes:
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]314
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]315<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]316 <li>Named values are represented as a string of characters with their prefix.
317 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
318 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]319 Identifiers which require other characters in their names can be surrounded
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]320 with quotes. In this way, anything except a <tt>&quot;</tt> character can
321 be used in a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]322
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]323 <li>Unnamed values are represented as an unsigned numeric value with their
324 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]325
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]326 <li>Constants, which are described in a <a href="#constants">section about
327 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]328</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]329
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]330<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]331don't need to worry about name clashes with reserved words, and the set of
332reserved words may be expanded in the future without penalty. Additionally,
333unnamed identifiers allow a compiler to quickly come up with a temporary
334variable without having to avoid symbol table conflicts.</p>
335
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]336<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]337languages. There are keywords for different opcodes
338('<tt><a href="#i_add">add</a></tt>',
339 '<tt><a href="#i_bitcast">bitcast</a></tt>',
340 '<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]341href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]342and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]343none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]344
345<p>Here is an example of LLVM code to multiply the integer variable
346'<tt>%X</tt>' by 8:</p>
347
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]348<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]349
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]350<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]351<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]352%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]353</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]354</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]355
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]356<p>After strength reduction:</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_shl">shl</a> i32 %X, i8 3
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>And the hard way:</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<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
369<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
370%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]371</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]372</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]373
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]374<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
375important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]376
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]377<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]378
379 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
380 line.</li>
381
382 <li>Unnamed temporaries are created when the result of a computation is not
383 assigned to a named value.</li>
384
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]385 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]387</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]388
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]389<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]390demonstrating instructions, we will follow an instruction with a comment that
391defines the type and name of value produced. Comments are shown in italic
392text.</p>
393
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]394</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]395
396<!-- *********************************************************************** -->
397<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
398<!-- *********************************************************************** -->
399
400<!-- ======================================================================= -->
401<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
402</div>
403
404<div class="doc_text">
405
406<p>LLVM programs are composed of "Module"s, each of which is a
407translation unit of the input programs. Each module consists of
408functions, global variables, and symbol table entries. Modules may be
409combined together with the LLVM linker, which merges function (and
410global variable) definitions, resolves forward declarations, and merges
411symbol table entries. Here is an example of the "hello world" module:</p>
412
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]413<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]414<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]415<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
416 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]417
418<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]419<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]420
421<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]422define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]423 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]424 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]425 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]426
427 <i>; Call puts function to write out the string to stdout...</i>
428 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]429 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]430 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]431 href="#i_ret">ret</a> i32 0<br>}<br>
432</pre>
433</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]434
435<p>This example is made up of a <a href="#globalvars">global variable</a>
436named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
437function, and a <a href="#functionstructure">function definition</a>
438for "<tt>main</tt>".</p>
439
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440<p>In general, a module is made up of a list of global values,
441where both functions and global variables are global values. Global values are
442represented by a pointer to a memory location (in this case, a pointer to an
443array of char, and a pointer to a function), and have one of the following <a
444href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]445
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446</div>
447
448<!-- ======================================================================= -->
449<div class="doc_subsection">
450 <a name="linkage">Linkage Types</a>
451</div>
452
453<div class="doc_text">
454
455<p>
456All Global Variables and Functions have one of the following types of linkage:
457</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]458
459<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]460
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]461 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]462
463 <dd>Global values with internal linkage are only directly accessible by
464 objects in the current module. In particular, linking code into a module with
465 an internal global value may cause the internal to be renamed as necessary to
466 avoid collisions. Because the symbol is internal to the module, all
467 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]468 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]473 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
474 the same name when linkage occurs. This is typically used to implement
475 inline functions, templates, or other code which must be generated in each
476 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
477 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]478 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]479
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]480 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]481
482 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
483 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]484 used for globals that may be emitted in multiple translation units, but that
485 are not guaranteed to be emitted into every translation unit that uses them.
486 One example of this are common globals in C, such as "<tt>int X;</tt>" at
487 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]488 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]489
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]490 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]491
492 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
493 pointer to array type. When two global variables with appending linkage are
494 linked together, the two global arrays are appended together. This is the
495 LLVM, typesafe, equivalent of having the system linker append together
496 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]498
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]499 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
500 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
501 until linked, if not linked, the symbol becomes null instead of being an
502 undefined reference.
503 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]504
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]506
507 <dd>If none of the above identifiers are used, the global is externally
508 visible, meaning that it participates in linkage and can be used to resolve
509 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]510 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]511</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]512
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]513 <p>
514 The next two types of linkage are targeted for Microsoft Windows platform
515 only. They are designed to support importing (exporting) symbols from (to)
516 DLLs.
517 </p>
518
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]519 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]520 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
521
522 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
523 or variable via a global pointer to a pointer that is set up by the DLL
524 exporting the symbol. On Microsoft Windows targets, the pointer name is
525 formed by combining <code>_imp__</code> and the function or variable name.
526 </dd>
527
528 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
529
530 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
531 pointer to a pointer in a DLL, so that it can be referenced with the
532 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
533 name is formed by combining <code>_imp__</code> and the function or variable
534 name.
535 </dd>
536
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]537</dl>
538
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]539<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]540variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
541variable and was linked with this one, one of the two would be renamed,
542preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
543external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]544outside of the current module.</p>
545<p>It is illegal for a function <i>declaration</i>
546to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]547or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]548<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
549linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]550</div>
551
552<!-- ======================================================================= -->
553<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]554 <a name="callingconv">Calling Conventions</a>
555</div>
556
557<div class="doc_text">
558
559<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
560and <a href="#i_invoke">invokes</a> can all have an optional calling convention
561specified for the call. The calling convention of any pair of dynamic
562caller/callee must match, or the behavior of the program is undefined. The
563following calling conventions are supported by LLVM, and more may be added in
564the future:</p>
565
566<dl>
567 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
568
569 <dd>This calling convention (the default if no other calling convention is
570 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]571 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]572 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]573 </dd>
574
575 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
576
577 <dd>This calling convention attempts to make calls as fast as possible
578 (e.g. by passing things in registers). This calling convention allows the
579 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]580 without having to conform to an externally specified ABI. Implementations of
581 this convention should allow arbitrary tail call optimization to be supported.
582 This calling convention does not support varargs and requires the prototype of
583 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]584 </dd>
585
586 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
587
588 <dd>This calling convention attempts to make code in the caller as efficient
589 as possible under the assumption that the call is not commonly executed. As
590 such, these calls often preserve all registers so that the call does not break
591 any live ranges in the caller side. This calling convention does not support
592 varargs and requires the prototype of all callees to exactly match the
593 prototype of the function definition.
594 </dd>
595
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]596 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]597
598 <dd>Any calling convention may be specified by number, allowing
599 target-specific calling conventions to be used. Target specific calling
600 conventions start at 64.
601 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]602</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]603
604<p>More calling conventions can be added/defined on an as-needed basis, to
605support pascal conventions or any other well-known target-independent
606convention.</p>
607
608</div>
609
610<!-- ======================================================================= -->
611<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]612 <a name="visibility">Visibility Styles</a>
613</div>
614
615<div class="doc_text">
616
617<p>
618All Global Variables and Functions have one of the following visibility styles:
619</p>
620
621<dl>
622 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
623
624 <dd>On ELF, default visibility means that the declaration is visible to other
625 modules and, in shared libraries, means that the declared entity may be
626 overridden. On Darwin, default visibility means that the declaration is
627 visible to other modules. Default visibility corresponds to "external
628 linkage" in the language.
629 </dd>
630
631 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
632
633 <dd>Two declarations of an object with hidden visibility refer to the same
634 object if they are in the same shared object. Usually, hidden visibility
635 indicates that the symbol will not be placed into the dynamic symbol table,
636 so no other module (executable or shared library) can reference it
637 directly.
638 </dd>
639
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]640 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
641
642 <dd>On ELF, protected visibility indicates that the symbol will be placed in
643 the dynamic symbol table, but that references within the defining module will
644 bind to the local symbol. That is, the symbol cannot be overridden by another
645 module.
646 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]647</dl>
648
649</div>
650
651<!-- ======================================================================= -->
652<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]653 <a name="globalvars">Global Variables</a>
654</div>
655
656<div class="doc_text">
657
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]658<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]659instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]660an explicit section to be placed in, and may have an optional explicit alignment
661specified. A variable may be defined as "thread_local", which means that it
662will not be shared by threads (each thread will have a separated copy of the
663variable). A variable may be defined as a global "constant," which indicates
664that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]665optimization, allowing the global data to be placed in the read-only section of
666an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]667cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]668
669<p>
670LLVM explicitly allows <em>declarations</em> of global variables to be marked
671constant, even if the final definition of the global is not. This capability
672can be used to enable slightly better optimization of the program, but requires
673the language definition to guarantee that optimizations based on the
674'constantness' are valid for the translation units that do not include the
675definition.
676</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]677
678<p>As SSA values, global variables define pointer values that are in
679scope (i.e. they dominate) all basic blocks in the program. Global
680variables always define a pointer to their "content" type because they
681describe a region of memory, and all memory objects in LLVM are
682accessed through pointers.</p>
683
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]684<p>A global variable may be declared to reside in a target-specifc numbered
685address space. For targets that support them, address spaces may affect how
686optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000[diff] [blame]687the variable. The default address space is zero. The address space qualifier
688must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]689
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]690<p>LLVM allows an explicit section to be specified for globals. If the target
691supports it, it will emit globals to the section specified.</p>
692
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]693<p>An explicit alignment may be specified for a global. If not present, or if
694the alignment is set to zero, the alignment of the global is set by the target
695to whatever it feels convenient. If an explicit alignment is specified, the
696global is forced to have at least that much alignment. All alignments must be
697a power of 2.</p>
698
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]699<p>For example, the following defines a global in a numbered address space with
700an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]701
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]702<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]703<pre>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]704@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]705</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]706</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]707
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]708</div>
709
710
711<!-- ======================================================================= -->
712<div class="doc_subsection">
713 <a name="functionstructure">Functions</a>
714</div>
715
716<div class="doc_text">
717
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]718<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
719an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]720<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]721<a href="#callingconv">calling convention</a>, a return type, an optional
722<a href="#paramattrs">parameter attribute</a> for the return type, a function
723name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]724<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]725optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]726opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]727
728LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
729optional <a href="#linkage">linkage type</a>, an optional
730<a href="#visibility">visibility style</a>, an optional
731<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]732<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]733name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]734<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]735
736<p>A function definition contains a list of basic blocks, forming the CFG for
737the function. Each basic block may optionally start with a label (giving the
738basic block a symbol table entry), contains a list of instructions, and ends
739with a <a href="#terminators">terminator</a> instruction (such as a branch or
740function return).</p>
741
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]742<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]743executed on entrance to the function, and it is not allowed to have predecessor
744basic blocks (i.e. there can not be any branches to the entry block of a
745function). Because the block can have no predecessors, it also cannot have any
746<a href="#i_phi">PHI nodes</a>.</p>
747
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]748<p>LLVM allows an explicit section to be specified for functions. If the target
749supports it, it will emit functions to the section specified.</p>
750
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]751<p>An explicit alignment may be specified for a function. If not present, or if
752the alignment is set to zero, the alignment of the function is set by the target
753to whatever it feels convenient. If an explicit alignment is specified, the
754function is forced to have at least that much alignment. All alignments must be
755a power of 2.</p>
756
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]757</div>
758
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]759
760<!-- ======================================================================= -->
761<div class="doc_subsection">
762 <a name="aliasstructure">Aliases</a>
763</div>
764<div class="doc_text">
765 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikovb18f8f82007-04-28 13:45:00 +0000[diff] [blame]766 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]767 optional <a href="#linkage">linkage type</a>, and an
768 optional <a href="#visibility">visibility style</a>.</p>
769
770 <h5>Syntax:</h5>
771
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]772<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]773<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]774@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]775</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]776</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]777
778</div>
779
780
781
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]782<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]783<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
784<div class="doc_text">
785 <p>The return type and each parameter of a function type may have a set of
786 <i>parameter attributes</i> associated with them. Parameter attributes are
787 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]788 a function. Parameter attributes are considered to be part of the function,
789 not of the function type, so functions with different parameter attributes
790 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]791
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]792 <p>Parameter attributes are simple keywords that follow the type specified. If
793 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]794 example:</p>
795
796<div class="doc_code">
797<pre>
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]798declare i32 @printf(i8* noalias , ...) nounwind
799declare i32 @atoi(i8*) nounwind readonly
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]800</pre>
801</div>
802
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]803 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
804 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]805
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]806 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]807 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]808 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]809 <dd>This indicates that the parameter should be zero extended just before
810 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]811
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]812 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]813 <dd>This indicates that the parameter should be sign extended just before
814 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]815
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]816 <dt><tt>inreg</tt></dt>
817 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]818 possible) during assembling function call. Support for this attribute is
819 target-specific</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]820
821 <dt><tt>byval</tt></dt>
Chris Lattner352ab9b2008-01-15 04:34:22 +0000[diff] [blame]822 <dd>This indicates that the pointer parameter should really be passed by
823 value to the function. The attribute implies that a hidden copy of the
824 pointee is made between the caller and the callee, so the callee is unable
825 to modify the value in the callee. This attribute is only valid on llvm
826 pointer arguments. It is generally used to pass structs and arrays by
827 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]828
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]829 <dt><tt>sret</tt></dt>
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]830 <dd>This indicates that the pointer parameter specifies the address of a
831 structure that is the return value of the function in the source program.
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]832 Loads and stores to the structure are assumed not to trap.
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000[diff] [blame]833 May only be applied to the first parameter.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]834
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]835 <dt><tt>noalias</tt></dt>
Owen Anderson61101282008-02-18 04:09:01 +0000[diff] [blame]836 <dd>This indicates that the parameter does not alias any global or any other
837 parameter. The caller is responsible for ensuring that this is the case,
838 usually by placing the value in a stack allocation.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]839
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]840 <dt><tt>noreturn</tt></dt>
841 <dd>This function attribute indicates that the function never returns. This
842 indicates to LLVM that every call to this function should be treated as if
843 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]844
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]845 <dt><tt>nounwind</tt></dt>
Duncan Sandsc572c1e2008-03-17 12:17:41 +0000[diff] [blame]846 <dd>This function attribute indicates that no exceptions unwind out of the
847 function. Usually this is because the function makes no use of exceptions,
848 but it may also be that the function catches any exceptions thrown when
849 executing it.</dd>
850
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]851 <dt><tt>nest</tt></dt>
852 <dd>This indicates that the parameter can be excised using the
853 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]854 <dt><tt>readonly</tt></dt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]855 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]856 except for producing a return value or throwing an exception. The value
857 returned must only depend on the function arguments and/or global variables.
858 It may use values obtained by dereferencing pointers.</dd>
859 <dt><tt>readnone</tt></dt>
860 <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]861 function, but in addition it is not allowed to dereference any pointer arguments
862 or global variables.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]863 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]864
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]865</div>
866
867<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]868<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]869 <a name="gc">Garbage Collector Names</a>
870</div>
871
872<div class="doc_text">
873<p>Each function may specify a garbage collector name, which is simply a
874string.</p>
875
876<div class="doc_code"><pre
877>define void @f() gc "name" { ...</pre></div>
878
879<p>The compiler declares the supported values of <i>name</i>. Specifying a
880collector which will cause the compiler to alter its output in order to support
881the named garbage collection algorithm.</p>
882</div>
883
884<!-- ======================================================================= -->
885<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]886 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]887</div>
888
889<div class="doc_text">
890<p>
891Modules may contain "module-level inline asm" blocks, which corresponds to the
892GCC "file scope inline asm" blocks. These blocks are internally concatenated by
893LLVM and treated as a single unit, but may be separated in the .ll file if
894desired. The syntax is very simple:
895</p>
896
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]897<div class="doc_code">
898<pre>
899module asm "inline asm code goes here"
900module asm "more can go here"
901</pre>
902</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]903
904<p>The strings can contain any character by escaping non-printable characters.
905 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
906 for the number.
907</p>
908
909<p>
910 The inline asm code is simply printed to the machine code .s file when
911 assembly code is generated.
912</p>
913</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]914
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]915<!-- ======================================================================= -->
916<div class="doc_subsection">
917 <a name="datalayout">Data Layout</a>
918</div>
919
920<div class="doc_text">
921<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]922data is to be laid out in memory. The syntax for the data layout is simply:</p>
923<pre> target datalayout = "<i>layout specification</i>"</pre>
924<p>The <i>layout specification</i> consists of a list of specifications
925separated by the minus sign character ('-'). Each specification starts with a
926letter and may include other information after the letter to define some
927aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]928<dl>
929 <dt><tt>E</tt></dt>
930 <dd>Specifies that the target lays out data in big-endian form. That is, the
931 bits with the most significance have the lowest address location.</dd>
932 <dt><tt>e</tt></dt>
933 <dd>Specifies that hte target lays out data in little-endian form. That is,
934 the bits with the least significance have the lowest address location.</dd>
935 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
936 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
937 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
938 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
939 too.</dd>
940 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
941 <dd>This specifies the alignment for an integer type of a given bit
942 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
943 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
944 <dd>This specifies the alignment for a vector type of a given bit
945 <i>size</i>.</dd>
946 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
947 <dd>This specifies the alignment for a floating point type of a given bit
948 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
949 (double).</dd>
950 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
951 <dd>This specifies the alignment for an aggregate type of a given bit
952 <i>size</i>.</dd>
953</dl>
954<p>When constructing the data layout for a given target, LLVM starts with a
955default set of specifications which are then (possibly) overriden by the
956specifications in the <tt>datalayout</tt> keyword. The default specifications
957are given in this list:</p>
958<ul>
959 <li><tt>E</tt> - big endian</li>
960 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
961 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
962 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
963 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
964 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
965 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
966 alignment of 64-bits</li>
967 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
968 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
969 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
970 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
971 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
972</ul>
973<p>When llvm is determining the alignment for a given type, it uses the
974following rules:
975<ol>
976 <li>If the type sought is an exact match for one of the specifications, that
977 specification is used.</li>
978 <li>If no match is found, and the type sought is an integer type, then the
979 smallest integer type that is larger than the bitwidth of the sought type is
980 used. If none of the specifications are larger than the bitwidth then the the
981 largest integer type is used. For example, given the default specifications
982 above, the i7 type will use the alignment of i8 (next largest) while both
983 i65 and i256 will use the alignment of i64 (largest specified).</li>
984 <li>If no match is found, and the type sought is a vector type, then the
985 largest vector type that is smaller than the sought vector type will be used
986 as a fall back. This happens because <128 x double> can be implemented in
987 terms of 64 <2 x double>, for example.</li>
988</ol>
989</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]990
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]991<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]992<div class="doc_section"> <a name="typesystem">Type System</a> </div>
993<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]994
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]995<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]996
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]997<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]998intermediate representation. Being typed enables a number of
999optimizations to be performed on the IR directly, without having to do
1000extra analyses on the side before the transformation. A strong type
1001system makes it easier to read the generated code and enables novel
1002analyses and transformations that are not feasible to perform on normal
1003three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1004
1005</div>
1006
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1007<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1008<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1009Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1010<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1011<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1012classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1013
1014<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1015 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1016 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1017 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1018 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1019 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1020 </tr>
1021 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1022 <td><a href="#t_floating">floating point</a></td>
1023 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1024 </tr>
1025 <tr>
1026 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1027 <td><a href="#t_integer">integer</a>,
1028 <a href="#t_floating">floating point</a>,
1029 <a href="#t_pointer">pointer</a>,
1030 <a href="#t_vector">vector</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1031 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1032 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1033 <tr>
1034 <td><a href="#t_primitive">primitive</a></td>
1035 <td><a href="#t_label">label</a>,
1036 <a href="#t_void">void</a>,
1037 <a href="#t_integer">integer</a>,
1038 <a href="#t_floating">floating point</a>.</td>
1039 </tr>
1040 <tr>
1041 <td><a href="#t_derived">derived</a></td>
1042 <td><a href="#t_integer">integer</a>,
1043 <a href="#t_array">array</a>,
1044 <a href="#t_function">function</a>,
1045 <a href="#t_pointer">pointer</a>,
1046 <a href="#t_struct">structure</a>,
1047 <a href="#t_pstruct">packed structure</a>,
1048 <a href="#t_vector">vector</a>,
1049 <a href="#t_opaque">opaque</a>.
1050 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1051 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1052</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1053
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1054<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1055most important. Values of these types are the only ones which can be
1056produced by instructions, passed as arguments, or used as operands to
1057instructions. This means that all structures and arrays must be
1058manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1059</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1060
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1061<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1062<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1063
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1064<div class="doc_text">
1065<p>The primitive types are the fundamental building blocks of the LLVM
1066system.</p>
1067
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1068</div>
1069
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1070<!-- _______________________________________________________________________ -->
1071<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1072
1073<div class="doc_text">
1074 <table>
1075 <tbody>
1076 <tr><th>Type</th><th>Description</th></tr>
1077 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1078 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1079 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1080 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1081 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1082 </tbody>
1083 </table>
1084</div>
1085
1086<!-- _______________________________________________________________________ -->
1087<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1088
1089<div class="doc_text">
1090<h5>Overview:</h5>
1091<p>The void type does not represent any value and has no size.</p>
1092
1093<h5>Syntax:</h5>
1094
1095<pre>
1096 void
1097</pre>
1098</div>
1099
1100<!-- _______________________________________________________________________ -->
1101<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1102
1103<div class="doc_text">
1104<h5>Overview:</h5>
1105<p>The label type represents code labels.</p>
1106
1107<h5>Syntax:</h5>
1108
1109<pre>
1110 label
1111</pre>
1112</div>
1113
1114
1115<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1116<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1117
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1118<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1119
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1120<p>The real power in LLVM comes from the derived types in the system.
1121This is what allows a programmer to represent arrays, functions,
1122pointers, and other useful types. Note that these derived types may be
1123recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1124
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1125</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1126
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1127<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1128<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1129
1130<div class="doc_text">
1131
1132<h5>Overview:</h5>
1133<p>The integer type is a very simple derived type that simply specifies an
1134arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11352^23-1 (about 8 million) can be specified.</p>
1136
1137<h5>Syntax:</h5>
1138
1139<pre>
1140 iN
1141</pre>
1142
1143<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1144value.</p>
1145
1146<h5>Examples:</h5>
1147<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1148 <tbody>
1149 <tr>
1150 <td><tt>i1</tt></td>
1151 <td>a single-bit integer.</td>
1152 </tr><tr>
1153 <td><tt>i32</tt></td>
1154 <td>a 32-bit integer.</td>
1155 </tr><tr>
1156 <td><tt>i1942652</tt></td>
1157 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1158 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1159 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1160</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1161</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1162
1163<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1164<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1165
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1166<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1167
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1168<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1169
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1170<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1171sequentially in memory. The array type requires a size (number of
1172elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1173
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1174<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1175
1176<pre>
1177 [&lt;# elements&gt; x &lt;elementtype&gt;]
1178</pre>
1179
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1180<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1181be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1182
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1183<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1184<table class="layout">
1185 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1186 <td class="left"><tt>[40 x i32]</tt></td>
1187 <td class="left">Array of 40 32-bit integer values.</td>
1188 </tr>
1189 <tr class="layout">
1190 <td class="left"><tt>[41 x i32]</tt></td>
1191 <td class="left">Array of 41 32-bit integer values.</td>
1192 </tr>
1193 <tr class="layout">
1194 <td class="left"><tt>[4 x i8]</tt></td>
1195 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1196 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1197</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1198<p>Here are some examples of multidimensional arrays:</p>
1199<table class="layout">
1200 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1201 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1202 <td class="left">3x4 array of 32-bit integer values.</td>
1203 </tr>
1204 <tr class="layout">
1205 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1206 <td class="left">12x10 array of single precision floating point values.</td>
1207 </tr>
1208 <tr class="layout">
1209 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1210 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1211 </tr>
1212</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1213
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1214<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1215length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1216LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1217As a special case, however, zero length arrays are recognized to be variable
1218length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1219type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1220
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1221</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1222
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1223<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1224<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1225<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1226<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1227<p>The function type can be thought of as a function signature. It
1228consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1229Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1230(which are structures of pointers to functions), for indirect function
1231calls, and when defining a function.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1232
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1233<h5>Syntax:</h5>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1234<pre> &lt;returntype list&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1235<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]1236specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1237which indicates that the function takes a variable number of arguments.
1238Variable argument functions can access their arguments with the <a
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1239 href="#int_varargs">variable argument handling intrinsic</a> functions.
1240'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1241<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1242<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1243<table class="layout">
1244 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1245 <td class="left"><tt>i32 (i32)</tt></td>
1246 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1247 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1248 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1249 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1250 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1251 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1252 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1253 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1254 <tt>float</tt>.
1255 </td>
1256 </tr><tr class="layout">
1257 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1258 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1259 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1260 which returns an integer. This is the signature for <tt>printf</tt> in
1261 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1262 </td>
1263 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1264</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1265
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1266</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1267<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1268<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1269<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1270<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1271<p>The structure type is used to represent a collection of data members
1272together in memory. The packing of the field types is defined to match
1273the ABI of the underlying processor. The elements of a structure may
1274be any type that has a size.</p>
1275<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1276and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1277field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1278instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1279<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1280<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1281<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1282<table class="layout">
1283 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1284 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1285 <td class="left">A triple of three <tt>i32</tt> values</td>
1286 </tr><tr class="layout">
1287 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1288 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1289 second element is a <a href="#t_pointer">pointer</a> to a
1290 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1291 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1292 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1293</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1294</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1295
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1296<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1297<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1298</div>
1299<div class="doc_text">
1300<h5>Overview:</h5>
1301<p>The packed structure type is used to represent a collection of data members
1302together in memory. There is no padding between fields. Further, the alignment
1303of a packed structure is 1 byte. The elements of a packed structure may
1304be any type that has a size.</p>
1305<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1306and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1307field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1308instruction.</p>
1309<h5>Syntax:</h5>
1310<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1311<h5>Examples:</h5>
1312<table class="layout">
1313 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1314 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1315 <td class="left">A triple of three <tt>i32</tt> values</td>
1316 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1317 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1318 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1319 second element is a <a href="#t_pointer">pointer</a> to a
1320 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1321 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1322 </tr>
1323</table>
1324</div>
1325
1326<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1327<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1328<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1329<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1330<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1331reference to another object, which must live in memory. Pointer types may have
1332an optional address space attribute defining the target-specific numbered
1333address space where the pointed-to object resides. The default address space is
1334zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1335<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1336<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1337<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1338<table class="layout">
1339 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1340 <td class="left"><tt>[4x i32]*</tt></td>
1341 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1342 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1343 </tr>
1344 <tr class="layout">
1345 <td class="left"><tt>i32 (i32 *) *</tt></td>
1346 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1347 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1348 <tt>i32</tt>.</td>
1349 </tr>
1350 <tr class="layout">
1351 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1352 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1353 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1354 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1355</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1356</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1357
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1358<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1359<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1360<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1361
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1362<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1363
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1364<p>A vector type is a simple derived type that represents a vector
1365of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1366are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1367A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1368elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1369of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1370considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1371
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1372<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1373
1374<pre>
1375 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1376</pre>
1377
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1378<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1379be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1380
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1381<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1382
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1383<table class="layout">
1384 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1385 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1386 <td class="left">Vector of 4 32-bit integer values.</td>
1387 </tr>
1388 <tr class="layout">
1389 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1390 <td class="left">Vector of 8 32-bit floating-point values.</td>
1391 </tr>
1392 <tr class="layout">
1393 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1394 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1395 </tr>
1396</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1397</div>
1398
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1399<!-- _______________________________________________________________________ -->
1400<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1401<div class="doc_text">
1402
1403<h5>Overview:</h5>
1404
1405<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1406corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1407In LLVM, opaque types can eventually be resolved to any type (not just a
1408structure type).</p>
1409
1410<h5>Syntax:</h5>
1411
1412<pre>
1413 opaque
1414</pre>
1415
1416<h5>Examples:</h5>
1417
1418<table class="layout">
1419 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1420 <td class="left"><tt>opaque</tt></td>
1421 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1422 </tr>
1423</table>
1424</div>
1425
1426
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1427<!-- *********************************************************************** -->
1428<div class="doc_section"> <a name="constants">Constants</a> </div>
1429<!-- *********************************************************************** -->
1430
1431<div class="doc_text">
1432
1433<p>LLVM has several different basic types of constants. This section describes
1434them all and their syntax.</p>
1435
1436</div>
1437
1438<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1439<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1440
1441<div class="doc_text">
1442
1443<dl>
1444 <dt><b>Boolean constants</b></dt>
1445
1446 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1447 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1448 </dd>
1449
1450 <dt><b>Integer constants</b></dt>
1451
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1452 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1453 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1454 integer types.
1455 </dd>
1456
1457 <dt><b>Floating point constants</b></dt>
1458
1459 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1460 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1461 notation (see below). Floating point constants must have a <a
1462 href="#t_floating">floating point</a> type. </dd>
1463
1464 <dt><b>Null pointer constants</b></dt>
1465
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1466 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1467 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1468
1469</dl>
1470
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1471<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1472of floating point constants. For example, the form '<tt>double
14730x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14744.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1475(and the only time that they are generated by the disassembler) is when a
1476floating point constant must be emitted but it cannot be represented as a
1477decimal floating point number. For example, NaN's, infinities, and other
1478special values are represented in their IEEE hexadecimal format so that
1479assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1480
1481</div>
1482
1483<!-- ======================================================================= -->
1484<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1485</div>
1486
1487<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1488<p>Aggregate constants arise from aggregation of simple constants
1489and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1490
1491<dl>
1492 <dt><b>Structure constants</b></dt>
1493
1494 <dd>Structure constants are represented with notation similar to structure
1495 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1496 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1497 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]1498 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1499 types of elements must match those specified by the type.
1500 </dd>
1501
1502 <dt><b>Array constants</b></dt>
1503
1504 <dd>Array constants are represented with notation similar to array type
1505 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1506 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1507 constants must have <a href="#t_array">array type</a>, and the number and
1508 types of elements must match those specified by the type.
1509 </dd>
1510
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1511 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1512
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1513 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1514 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1515 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]1516 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1517 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1518 match those specified by the type.
1519 </dd>
1520
1521 <dt><b>Zero initialization</b></dt>
1522
1523 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1524 value to zero of <em>any</em> type, including scalar and aggregate types.
1525 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]1526 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1527 initializers.
1528 </dd>
1529</dl>
1530
1531</div>
1532
1533<!-- ======================================================================= -->
1534<div class="doc_subsection">
1535 <a name="globalconstants">Global Variable and Function Addresses</a>
1536</div>
1537
1538<div class="doc_text">
1539
1540<p>The addresses of <a href="#globalvars">global variables</a> and <a
1541href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1542constants. These constants are explicitly referenced when the <a
1543href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1544href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1545file:</p>
1546
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1547<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1548<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1549@X = global i32 17
1550@Y = global i32 42
1551@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1552</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1553</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1554
1555</div>
1556
1557<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1558<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1559<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1560 <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]1561 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1562 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1563
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1564 <p>Undefined values indicate to the compiler that the program is well defined
1565 no matter what value is used, giving the compiler more freedom to optimize.
1566 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1567</div>
1568
1569<!-- ======================================================================= -->
1570<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1571</div>
1572
1573<div class="doc_text">
1574
1575<p>Constant expressions are used to allow expressions involving other constants
1576to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1577href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1578that does not have side effects (e.g. load and call are not supported). The
1579following is the syntax for constant expressions:</p>
1580
1581<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1582 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1583 <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]1584 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1585
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1586 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1587 <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]1588 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]1589
1590 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1591 <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]1592 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]1593
1594 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1595 <dd>Truncate a floating point constant to another floating point type. The
1596 size of CST must be larger than the size of TYPE. Both types must be
1597 floating point.</dd>
1598
1599 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1600 <dd>Floating point extend a constant to another type. The size of CST must be
1601 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1602
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1603 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1604 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1605 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1606 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1607 of the same number of elements. If the value won't fit in the integer type,
1608 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1609
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1610 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1611 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1612 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1613 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1614 of the same number of elements. If the value won't fit in the integer type,
1615 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1616
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1617 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1618 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1619 constant. TYPE must be a scalar or vector floating point type. CST must be of
1620 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1621 of the same number of elements. If the value won't fit in the floating point
1622 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1623
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1624 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1625 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1626 constant. TYPE must be a scalar or vector floating point type. CST must be of
1627 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1628 of the same number of elements. If the value won't fit in the floating point
1629 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1630
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1631 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1632 <dd>Convert a pointer typed constant to the corresponding integer constant
1633 TYPE must be an integer type. CST must be of pointer type. The CST value is
1634 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1635
1636 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1637 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1638 pointer type. CST must be of integer type. The CST value is zero extended,
1639 truncated, or unchanged to make it fit in a pointer size. This one is
1640 <i>really</i> dangerous!</dd>
1641
1642 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1643 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1644 identical (same number of bits). The conversion is done as if the CST value
1645 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]1646 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1647 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]1648 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1649 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1650
1651 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1652
1653 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1654 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1655 instruction, the index list may have zero or more indexes, which are required
1656 to make sense for the type of "CSTPTR".</dd>
1657
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1658 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1659
1660 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1661 constants.</dd>
1662
1663 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1664 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1665
1666 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1667 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1668
1669 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1670
1671 <dd>Perform the <a href="#i_extractelement">extractelement
1672 operation</a> on constants.
1673
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1674 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1675
1676 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1677 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1678
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1679
1680 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1681
1682 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1683 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1684
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1685 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1686
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1687 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1688 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1689 binary</a> operations. The constraints on operands are the same as those for
1690 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1691 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1692</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1693</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1694
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1695<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1696<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1697<!-- *********************************************************************** -->
1698
1699<!-- ======================================================================= -->
1700<div class="doc_subsection">
1701<a name="inlineasm">Inline Assembler Expressions</a>
1702</div>
1703
1704<div class="doc_text">
1705
1706<p>
1707LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1708Module-Level Inline Assembly</a>) through the use of a special value. This
1709value represents the inline assembler as a string (containing the instructions
1710to emit), a list of operand constraints (stored as a string), and a flag that
1711indicates whether or not the inline asm expression has side effects. An example
1712inline assembler expression is:
1713</p>
1714
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1715<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1716<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1717i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1718</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1719</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1720
1721<p>
1722Inline assembler expressions may <b>only</b> be used as the callee operand of
1723a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1724</p>
1725
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1726<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1727<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1728%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]1729</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1730</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1731
1732<p>
1733Inline asms with side effects not visible in the constraint list must be marked
1734as having side effects. This is done through the use of the
1735'<tt>sideeffect</tt>' keyword, like so:
1736</p>
1737
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1738<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1739<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1740call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1741</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1742</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1743
1744<p>TODO: The format of the asm and constraints string still need to be
1745documented here. Constraints on what can be done (e.g. duplication, moving, etc
1746need to be documented).
1747</p>
1748
1749</div>
1750
1751<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1752<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1753<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1754
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1755<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1756
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1757<p>The LLVM instruction set consists of several different
1758classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1759instructions</a>, <a href="#binaryops">binary instructions</a>,
1760<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1761 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1762instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1763
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1764</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1765
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1766<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1767<div class="doc_subsection"> <a name="terminators">Terminator
1768Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1769
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1770<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1771
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1772<p>As mentioned <a href="#functionstructure">previously</a>, every
1773basic block in a program ends with a "Terminator" instruction, which
1774indicates which block should be executed after the current block is
1775finished. These terminator instructions typically yield a '<tt>void</tt>'
1776value: they produce control flow, not values (the one exception being
1777the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1778<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1779 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1780instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1781the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1782 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1783 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1784
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1785</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1786
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1787<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1788<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1789Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1790<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1791<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1792<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]1793 ret void <i>; Return from void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1794 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]1795</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1796<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1797<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1798value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1799<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1800returns a value and then causes control flow, and one that just causes
1801control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1802<h5>Arguments:</h5>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1803<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1804type of each return value must be a '<a href="#t_firstclass">first class</a>'
1805 type. Note that a function is not <a href="#wellformed">well formed</a>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1806if there exists a '<tt>ret</tt>' instruction inside of the function that
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1807returns values that do not match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1809<p>When the '<tt>ret</tt>' instruction is executed, control flow
1810returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1811 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1812the instruction after the call. If the caller was an "<a
1813 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1814at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1815returns a value, that value shall set the call or invoke instruction's
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1816return value. If the instruction returns multiple values then these
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1817values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1818</a>' instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1819<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1820<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1821 ret void <i>; Return from a void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1822 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1823</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1824</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1825<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1826<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1827<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1829<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]1830</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1831<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1832<p>The '<tt>br</tt>' instruction is used to cause control flow to
1833transfer to a different basic block in the current function. There are
1834two forms of this instruction, corresponding to a conditional branch
1835and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1836<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1837<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1838single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1839unconditional form of the '<tt>br</tt>' instruction takes a single
1840'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1841<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1842<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1843argument is evaluated. If the value is <tt>true</tt>, control flows
1844to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1845control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1846<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1847<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]1848 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]1849</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1850<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1851<div class="doc_subsubsection">
1852 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1853</div>
1854
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1855<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1856<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1857
1858<pre>
1859 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1860</pre>
1861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1862<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1863
1864<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1865several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1866instruction, allowing a branch to occur to one of many possible
1867destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1868
1869
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1870<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1871
1872<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1873comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1874an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1875table is not allowed to contain duplicate constant entries.</p>
1876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1878
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1879<p>The <tt>switch</tt> instruction specifies a table of values and
1880destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1881table is searched for the given value. If the value is found, control flow is
1882transfered to the corresponding destination; otherwise, control flow is
1883transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1884
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1885<h5>Implementation:</h5>
1886
1887<p>Depending on properties of the target machine and the particular
1888<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1889ways. For example, it could be generated as a series of chained conditional
1890branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1891
1892<h5>Example:</h5>
1893
1894<pre>
1895 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1896 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1897 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1898
1899 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1900 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1901
1902 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1903 switch i32 %val, label %otherwise [ i32 0, label %onzero
1904 i32 1, label %onone
1905 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1906</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1907</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1908
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1909<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1910<div class="doc_subsubsection">
1911 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1912</div>
1913
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1914<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1917
1918<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1919 &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]1920 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1921</pre>
1922
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1923<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1924
1925<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1926function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1927'<tt>normal</tt>' label or the
1928'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1929"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1930"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1931href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1932continued at the dynamically nearest "exception" label. If the callee function
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1933returns multiple values then individual return values are only accessible through
1934a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1935
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1936<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1937
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1938<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1939
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1940<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1941 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1942 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1943 convention</a> the call should use. If none is specified, the call defaults
1944 to using C calling conventions.
1945 </li>
1946 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1947 function value being invoked. In most cases, this is a direct function
1948 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1949 an arbitrary pointer to function value.
1950 </li>
1951
1952 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1953 function to be invoked. </li>
1954
1955 <li>'<tt>function args</tt>': argument list whose types match the function
1956 signature argument types. If the function signature indicates the function
1957 accepts a variable number of arguments, the extra arguments can be
1958 specified. </li>
1959
1960 <li>'<tt>normal label</tt>': the label reached when the called function
1961 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1962
1963 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1964 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1966</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1967
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1968<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1969
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1970<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1971href="#i_call">call</a></tt>' instruction in most regards. The primary
1972difference is that it establishes an association with a label, which is used by
1973the runtime library to unwind the stack.</p>
1974
1975<p>This instruction is used in languages with destructors to ensure that proper
1976cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1977exception. Additionally, this is important for implementation of
1978'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1979
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1980<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1981<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1982 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1983 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1984 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1985 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1986</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1987</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1988
1989
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1990<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1991
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1992<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1993Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1994
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1995<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1996
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1997<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1998<pre>
1999 unwind
2000</pre>
2001
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2002<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2003
2004<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2005at the first callee in the dynamic call stack which used an <a
2006href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2007primarily used to implement exception handling.</p>
2008
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2009<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2010
2011<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
2012immediately halt. The dynamic call stack is then searched for the first <a
2013href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2014execution continues at the "exceptional" destination block specified by the
2015<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2016dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2017</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2018
2019<!-- _______________________________________________________________________ -->
2020
2021<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2022Instruction</a> </div>
2023
2024<div class="doc_text">
2025
2026<h5>Syntax:</h5>
2027<pre>
2028 unreachable
2029</pre>
2030
2031<h5>Overview:</h5>
2032
2033<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2034instruction is used to inform the optimizer that a particular portion of the
2035code is not reachable. This can be used to indicate that the code after a
2036no-return function cannot be reached, and other facts.</p>
2037
2038<h5>Semantics:</h5>
2039
2040<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2041</div>
2042
2043
2044
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2045<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2046<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2047<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2048<p>Binary operators are used to do most of the computation in a
2049program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2050produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2051multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2052The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2053necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2054<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2055</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2056<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2057<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2058Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2059<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2060<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2061<pre> &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]2062</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2063<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2064<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2065<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2066<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2067 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2068 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2069Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2070<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2071<p>The value produced is the integer or floating point sum of the two
2072operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2073<p>If an integer sum has unsigned overflow, the result returned is the
2074mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2075the result.</p>
2076<p>Because LLVM integers use a two's complement representation, this
2077instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2078<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2079<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2080</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2081</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2082<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2083<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2084Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2085<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2087<pre> &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]2088</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2089<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2090<p>The '<tt>sub</tt>' instruction returns the difference of its two
2091operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2092<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2093instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2095<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2096 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2097values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2098This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2099Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2100<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2101<p>The value produced is the integer or floating point difference of
2102the two operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2103<p>If an integer difference has unsigned overflow, the result returned is the
2104mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2105the result.</p>
2106<p>Because LLVM integers use a two's complement representation, this
2107instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2108<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2109<pre>
2110 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2111 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2112</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2113</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2114<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2115<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2116Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2117<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2118<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2119<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]2120</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2122<p>The '<tt>mul</tt>' instruction returns the product of its two
2123operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2124<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2125<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2126 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2127values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2128This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2129Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2130<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2131<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2132two operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2133<p>If the result of an integer multiplication has unsigned overflow,
2134the result returned is the mathematical result modulo
21352<sup>n</sup>, where n is the bit width of the result.</p>
2136<p>Because LLVM integers use a two's complement representation, and the
2137result is the same width as the operands, this instruction returns the
2138correct result for both signed and unsigned integers. If a full product
2139(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2140should be sign-extended or zero-extended as appropriate to the
2141width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2142<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2143<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]2144</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2145</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2146<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2147<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2148</a></div>
2149<div class="doc_text">
2150<h5>Syntax:</h5>
2151<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2152</pre>
2153<h5>Overview:</h5>
2154<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2155operands.</p>
2156<h5>Arguments:</h5>
2157<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2158<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2159types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2160of the values in which case the elements must be integers.</p>
2161<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2162<p>The value produced is the unsigned integer quotient of the two operands.</p>
2163<p>Note that unsigned integer division and signed integer division are distinct
2164operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2165<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2166<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2167<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]2168</pre>
2169</div>
2170<!-- _______________________________________________________________________ -->
2171<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2172</a> </div>
2173<div class="doc_text">
2174<h5>Syntax:</h5>
2175<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2176</pre>
2177<h5>Overview:</h5>
2178<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2179operands.</p>
2180<h5>Arguments:</h5>
2181<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2182<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2183types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2184of the values in which case the elements must be integers.</p>
2185<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2186<p>The value produced is the signed integer quotient of the two operands.</p>
2187<p>Note that signed integer division and unsigned integer division are distinct
2188operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2189<p>Division by zero leads to undefined behavior. Overflow also leads to
2190undefined behavior; this is a rare case, but can occur, for example,
2191by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2192<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2193<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]2194</pre>
2195</div>
2196<!-- _______________________________________________________________________ -->
2197<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2198Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2199<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2200<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2201<pre> &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]2202</pre>
2203<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2204<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2205operands.</p>
2206<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2207<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2208<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2209identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2210versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2211<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2212<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2213<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2214<pre> &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]2215</pre>
2216</div>
2217<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2218<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2219</div>
2220<div class="doc_text">
2221<h5>Syntax:</h5>
2222<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2223</pre>
2224<h5>Overview:</h5>
2225<p>The '<tt>urem</tt>' instruction returns the remainder from the
2226unsigned division of its two arguments.</p>
2227<h5>Arguments:</h5>
2228<p>The two arguments to the '<tt>urem</tt>' instruction must be
2229<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2230types. This instruction can also take <a href="#t_vector">vector</a> versions
2231of the values in which case the elements must be integers.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2232<h5>Semantics:</h5>
2233<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2234This instruction always performs an unsigned division to get the remainder,
2235regardless of whether the arguments are unsigned or not.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2236<p>Note that unsigned integer remainder and signed integer remainder are
2237distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2238<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2239<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2240<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]2241</pre>
2242
2243</div>
2244<!-- _______________________________________________________________________ -->
2245<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2246Instruction</a> </div>
2247<div class="doc_text">
2248<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2249<pre> &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]2250</pre>
2251<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2252<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2253signed division of its two operands. This instruction can also take
2254<a href="#t_vector">vector</a> versions of the values in which case
2255the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2256
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2257<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2258<p>The two arguments to the '<tt>srem</tt>' instruction must be
2259<a href="#t_integer">integer</a> values. Both arguments must have identical
2260types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2261<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2262<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2263has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2264operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2265a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2266 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2267Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2268please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2269Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2270<p>Note that signed integer remainder and unsigned integer remainder are
2271distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2272<p>Taking the remainder of a division by zero leads to undefined behavior.
2273Overflow also leads to undefined behavior; this is a rare case, but can occur,
2274for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2275(The remainder doesn't actually overflow, but this rule lets srem be
2276implemented using instructions that return both the result of the division
2277and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2278<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2279<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]2280</pre>
2281
2282</div>
2283<!-- _______________________________________________________________________ -->
2284<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2285Instruction</a> </div>
2286<div class="doc_text">
2287<h5>Syntax:</h5>
2288<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2289</pre>
2290<h5>Overview:</h5>
2291<p>The '<tt>frem</tt>' instruction returns the remainder from the
2292division of its two operands.</p>
2293<h5>Arguments:</h5>
2294<p>The two arguments to the '<tt>frem</tt>' instruction must be
2295<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2296identical types. This instruction can also take <a href="#t_vector">vector</a>
2297versions of floating point values.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2298<h5>Semantics:</h5>
2299<p>This instruction returns the <i>remainder</i> of a division.</p>
2300<h5>Example:</h5>
2301<pre> &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]2302</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2303</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2304
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2305<!-- ======================================================================= -->
2306<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2307Operations</a> </div>
2308<div class="doc_text">
2309<p>Bitwise binary operators are used to do various forms of
2310bit-twiddling in a program. They are generally very efficient
2311instructions and can commonly be strength reduced from other
2312instructions. They require two operands, execute an operation on them,
2313and produce a single value. The resulting value of the bitwise binary
2314operators is always the same type as its first operand.</p>
2315</div>
2316
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2317<!-- _______________________________________________________________________ -->
2318<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2319Instruction</a> </div>
2320<div class="doc_text">
2321<h5>Syntax:</h5>
2322<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2323</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2324
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2325<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2326
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2327<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2328the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2329
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2330<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2331
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2332<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2333 href="#t_integer">integer</a> type.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2334
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2335<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2336
2337<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2338<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2339of bits in <tt>var1</tt>, the result is undefined.</p>
2340
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2341<h5>Example:</h5><pre>
2342 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2343 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2344 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2345 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2346</pre>
2347</div>
2348<!-- _______________________________________________________________________ -->
2349<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2350Instruction</a> </div>
2351<div class="doc_text">
2352<h5>Syntax:</h5>
2353<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2354</pre>
2355
2356<h5>Overview:</h5>
2357<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2358operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2359
2360<h5>Arguments:</h5>
2361<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2362<a href="#t_integer">integer</a> type.</p>
2363
2364<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2365
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2366<p>This instruction always performs a logical shift right operation. The most
2367significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2368shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2369the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2370
2371<h5>Example:</h5>
2372<pre>
2373 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2374 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2375 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2376 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2377 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2378</pre>
2379</div>
2380
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2381<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2382<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2383Instruction</a> </div>
2384<div class="doc_text">
2385
2386<h5>Syntax:</h5>
2387<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2388</pre>
2389
2390<h5>Overview:</h5>
2391<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2392operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2393
2394<h5>Arguments:</h5>
2395<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2396<a href="#t_integer">integer</a> type.</p>
2397
2398<h5>Semantics:</h5>
2399<p>This instruction always performs an arithmetic shift right operation,
2400The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2401of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2402larger than the number of bits in <tt>var1</tt>, the result is undefined.
2403</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2404
2405<h5>Example:</h5>
2406<pre>
2407 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2408 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2409 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2410 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2411 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2412</pre>
2413</div>
2414
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2415<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2416<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2417Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2418<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2419<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2420<pre> &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]2421</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2422<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2423<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2424its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2425<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2426<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2427 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2428identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2429<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2430<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2431<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2432<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2433<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2434 <tbody>
2435 <tr>
2436 <td>In0</td>
2437 <td>In1</td>
2438 <td>Out</td>
2439 </tr>
2440 <tr>
2441 <td>0</td>
2442 <td>0</td>
2443 <td>0</td>
2444 </tr>
2445 <tr>
2446 <td>0</td>
2447 <td>1</td>
2448 <td>0</td>
2449 </tr>
2450 <tr>
2451 <td>1</td>
2452 <td>0</td>
2453 <td>0</td>
2454 </tr>
2455 <tr>
2456 <td>1</td>
2457 <td>1</td>
2458 <td>1</td>
2459 </tr>
2460 </tbody>
2461</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2462</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2463<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2464<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2465 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2466 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2467</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2468</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2469<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2470<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2471<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2472<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2473<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]2474</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2475<h5>Overview:</h5>
2476<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2477or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2478<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2479<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2480 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2481identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2482<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2483<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2484<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2485<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2486<table border="1" cellspacing="0" cellpadding="4">
2487 <tbody>
2488 <tr>
2489 <td>In0</td>
2490 <td>In1</td>
2491 <td>Out</td>
2492 </tr>
2493 <tr>
2494 <td>0</td>
2495 <td>0</td>
2496 <td>0</td>
2497 </tr>
2498 <tr>
2499 <td>0</td>
2500 <td>1</td>
2501 <td>1</td>
2502 </tr>
2503 <tr>
2504 <td>1</td>
2505 <td>0</td>
2506 <td>1</td>
2507 </tr>
2508 <tr>
2509 <td>1</td>
2510 <td>1</td>
2511 <td>1</td>
2512 </tr>
2513 </tbody>
2514</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2515</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2516<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2517<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2518 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2519 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2520</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2521</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2522<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2523<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2524Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2525<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2526<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2527<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]2528</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2529<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2530<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2531or of its two operands. The <tt>xor</tt> is used to implement the
2532"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2533<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2534<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2535 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2536identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2537<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2538<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2539<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2540<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2541<table border="1" cellspacing="0" cellpadding="4">
2542 <tbody>
2543 <tr>
2544 <td>In0</td>
2545 <td>In1</td>
2546 <td>Out</td>
2547 </tr>
2548 <tr>
2549 <td>0</td>
2550 <td>0</td>
2551 <td>0</td>
2552 </tr>
2553 <tr>
2554 <td>0</td>
2555 <td>1</td>
2556 <td>1</td>
2557 </tr>
2558 <tr>
2559 <td>1</td>
2560 <td>0</td>
2561 <td>1</td>
2562 </tr>
2563 <tr>
2564 <td>1</td>
2565 <td>1</td>
2566 <td>0</td>
2567 </tr>
2568 </tbody>
2569</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2570</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2571<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2572<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2573<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2574 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2575 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2576 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2577</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2578</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2579
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2580<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2581<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2582 <a name="vectorops">Vector Operations</a>
2583</div>
2584
2585<div class="doc_text">
2586
2587<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2588target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2589vector-specific operations needed to process vectors effectively. While LLVM
2590does directly support these vector operations, many sophisticated algorithms
2591will want to use target-specific intrinsics to take full advantage of a specific
2592target.</p>
2593
2594</div>
2595
2596<!-- _______________________________________________________________________ -->
2597<div class="doc_subsubsection">
2598 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2599</div>
2600
2601<div class="doc_text">
2602
2603<h5>Syntax:</h5>
2604
2605<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2606 &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]2607</pre>
2608
2609<h5>Overview:</h5>
2610
2611<p>
2612The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2613element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2614</p>
2615
2616
2617<h5>Arguments:</h5>
2618
2619<p>
2620The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2621value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2622an index indicating the position from which to extract the element.
2623The index may be a variable.</p>
2624
2625<h5>Semantics:</h5>
2626
2627<p>
2628The result is a scalar of the same type as the element type of
2629<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2630<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2631results are undefined.
2632</p>
2633
2634<h5>Example:</h5>
2635
2636<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2637 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2638</pre>
2639</div>
2640
2641
2642<!-- _______________________________________________________________________ -->
2643<div class="doc_subsubsection">
2644 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2645</div>
2646
2647<div class="doc_text">
2648
2649<h5>Syntax:</h5>
2650
2651<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2652 &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]2653</pre>
2654
2655<h5>Overview:</h5>
2656
2657<p>
2658The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2659element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2660</p>
2661
2662
2663<h5>Arguments:</h5>
2664
2665<p>
2666The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2667value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2668scalar value whose type must equal the element type of the first
2669operand. The third operand is an index indicating the position at
2670which to insert the value. The index may be a variable.</p>
2671
2672<h5>Semantics:</h5>
2673
2674<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2675The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2676element values are those of <tt>val</tt> except at position
2677<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2678exceeds the length of <tt>val</tt>, the results are undefined.
2679</p>
2680
2681<h5>Example:</h5>
2682
2683<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2684 %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]2685</pre>
2686</div>
2687
2688<!-- _______________________________________________________________________ -->
2689<div class="doc_subsubsection">
2690 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2691</div>
2692
2693<div class="doc_text">
2694
2695<h5>Syntax:</h5>
2696
2697<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2698 &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]2699</pre>
2700
2701<h5>Overview:</h5>
2702
2703<p>
2704The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2705from two input vectors, returning a vector of the same type.
2706</p>
2707
2708<h5>Arguments:</h5>
2709
2710<p>
2711The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2712with types that match each other and types that match the result of the
2713instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2714of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2715</p>
2716
2717<p>
2718The shuffle mask operand is required to be a constant vector with either
2719constant integer or undef values.
2720</p>
2721
2722<h5>Semantics:</h5>
2723
2724<p>
2725The elements of the two input vectors are numbered from left to right across
2726both of the vectors. The shuffle mask operand specifies, for each element of
2727the result vector, which element of the two input registers the result element
2728gets. The element selector may be undef (meaning "don't care") and the second
2729operand may be undef if performing a shuffle from only one vector.
2730</p>
2731
2732<h5>Example:</h5>
2733
2734<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2735 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2736 &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]2737 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2738 &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]2739</pre>
2740</div>
2741
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2742
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2743<!-- ======================================================================= -->
2744<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2745 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2746</div>
2747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2748<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2749
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2750<p>A key design point of an SSA-based representation is how it
2751represents memory. In LLVM, no memory locations are in SSA form, which
2752makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2753allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2754
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2755</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2756
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2757<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2758<div class="doc_subsubsection">
2759 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2760</div>
2761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2762<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2764<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2765
2766<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2767 &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]2768</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2769
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2770<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2771
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2772<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2773heap and returns a pointer to it. The object is always allocated in the generic
2774address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2775
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2776<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2777
2778<p>The '<tt>malloc</tt>' instruction allocates
2779<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2780bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2781appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]2782number of elements allocated, otherwise "NumElements" is defaulted to be one.
2783If an alignment is specified, the value result of the allocation is guaranteed to
2784be aligned to at least that boundary. If not specified, or if zero, the target can
2785choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2786
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2787<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2788
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2789<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2790
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2791<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2792a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2793
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2794<h5>Example:</h5>
2795
2796<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2797 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2798
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2799 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2800 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2801 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2802 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2803 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2804</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2805</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2806
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2807<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2808<div class="doc_subsubsection">
2809 <a name="i_free">'<tt>free</tt>' Instruction</a>
2810</div>
2811
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2812<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2813
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2814<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2815
2816<pre>
2817 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2818</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2820<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2821
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2822<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2823memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2826
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2827<p>'<tt>value</tt>' shall be a pointer value that points to a value
2828that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2829instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2830
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2831<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2832
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2833<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2834after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2835
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2836<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2837
2838<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2839 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2840 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2841</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2842</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2843
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2845<div class="doc_subsubsection">
2846 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2847</div>
2848
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2849<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2851<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2852
2853<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2854 &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]2855</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2856
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2857<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2858
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2859<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2860currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2861returns to its caller. The object is always allocated in the generic address
2862space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2863
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2864<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2865
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2866<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2867bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]2868appropriate type to the program. If "NumElements" is specified, it is the
2869number of elements allocated, otherwise "NumElements" is defaulted to be one.
2870If an alignment is specified, the value result of the allocation is guaranteed
2871to be aligned to at least that boundary. If not specified, or if zero, the target
2872can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2873
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2874<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2875
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2876<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2877
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2878<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2879memory is automatically released when the function returns. The '<tt>alloca</tt>'
2880instruction is commonly used to represent automatic variables that must
2881have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2882 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2883instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2884
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2885<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2886
2887<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2888 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2889 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2890 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2891 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2892</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2893</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2894
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2895<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2896<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2897Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2898<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2899<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2900<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]2901<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2902<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2903<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2904<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2905address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2906 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2907marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2908the number or order of execution of this <tt>load</tt> with other
2909volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2910instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2911<p>
2912The optional "align" argument specifies the alignment of the operation
2913(that is, the alignment of the memory address). A value of 0 or an
2914omitted "align" argument means that the operation has the preferential
2915alignment for the target. It is the responsibility of the code emitter
2916to ensure that the alignment information is correct. Overestimating
2917the alignment results in an undefined behavior. Underestimating the
2918alignment may produce less efficient code. An alignment of 1 is always
2919safe.
2920</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2921<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2922<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2923<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2924<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2925 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2926 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2927 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2928</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2929</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2930<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2931<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2932Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2933<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2934<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2935<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2936 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]2937</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2938<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2939<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2940<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2941<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2942to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2943operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2944operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2945optimizer is not allowed to modify the number or order of execution of
2946this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2947 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2948<p>
2949The optional "align" argument specifies the alignment of the operation
2950(that is, the alignment of the memory address). A value of 0 or an
2951omitted "align" argument means that the operation has the preferential
2952alignment for the target. It is the responsibility of the code emitter
2953to ensure that the alignment information is correct. Overestimating
2954the alignment results in an undefined behavior. Underestimating the
2955alignment may produce less efficient code. An alignment of 1 is always
2956safe.
2957</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2958<h5>Semantics:</h5>
2959<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2960at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2961<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2962<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]2963 store i32 3, i32* %ptr <i>; yields {void}</i>
2964 %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]2965</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2966</div>
2967
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2968<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2969<div class="doc_subsubsection">
2970 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2971</div>
2972
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2973<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2974<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2975<pre>
2976 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2977</pre>
2978
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2979<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2980
2981<p>
2982The '<tt>getelementptr</tt>' instruction is used to get the address of a
2983subelement of an aggregate data structure.</p>
2984
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2985<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2986
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2987<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2988elements of the aggregate object to index to. The actual types of the arguments
2989provided depend on the type of the first pointer argument. The
2990'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2991levels 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]2992structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2993into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2994be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2995
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2996<p>For example, let's consider a C code fragment and how it gets
2997compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2998
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2999<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3000<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3001struct RT {
3002 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3003 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3004 char C;
3005};
3006struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3007 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3008 double Y;
3009 struct RT Z;
3010};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3011
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3012int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3013 return &amp;s[1].Z.B[5][13];
3014}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3015</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3016</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3017
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3018<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3019
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3020<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3021<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3022%RT = type { i8 , [10 x [20 x i32]], i8 }
3023%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3024
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3025define i32* %foo(%ST* %s) {
3026entry:
3027 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3028 ret i32* %reg
3029}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3030</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3031</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3032
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3033<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3034
3035<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3036on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3037and <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]3038<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3039to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]3040<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3041
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3042<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]3043type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3044}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3045the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3046i8 }</tt>' type, another structure. The third index indexes into the second
3047element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3048array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3049'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3050to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3051
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3052<p>Note that it is perfectly legal to index partially through a
3053structure, returning a pointer to an inner element. Because of this,
3054the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3055
3056<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3057 define i32* %foo(%ST* %s) {
3058 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3059 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3060 %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]3061 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3062 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3063 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3064 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3065</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3066
3067<p>Note that it is undefined to access an array out of bounds: array and
3068pointer indexes must always be within the defined bounds of the array type.
3069The one exception for this rules is zero length arrays. These arrays are
3070defined to be accessible as variable length arrays, which requires access
3071beyond the zero'th element.</p>
3072
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3073<p>The getelementptr instruction is often confusing. For some more insight
3074into how it works, see <a href="GetElementPtr.html">the getelementptr
3075FAQ</a>.</p>
3076
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3077<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3078
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3079<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3080 <i>; yields [12 x i8]*:aptr</i>
3081 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3082</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3083</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3084
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3085<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3086<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3087</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3088<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3089<p>The instructions in this category are the conversion instructions (casting)
3090which all take a single operand and a type. They perform various bit conversions
3091on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3092</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3093
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3094<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3095<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3096 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3097</div>
3098<div class="doc_text">
3099
3100<h5>Syntax:</h5>
3101<pre>
3102 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3103</pre>
3104
3105<h5>Overview:</h5>
3106<p>
3107The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3108</p>
3109
3110<h5>Arguments:</h5>
3111<p>
3112The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3113be 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]3114and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3115type. The bit size of <tt>value</tt> must be larger than the bit size of
3116<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3117
3118<h5>Semantics:</h5>
3119<p>
3120The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3121and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3122larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3123It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3124
3125<h5>Example:</h5>
3126<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3127 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3128 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3129 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3130</pre>
3131</div>
3132
3133<!-- _______________________________________________________________________ -->
3134<div class="doc_subsubsection">
3135 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3136</div>
3137<div class="doc_text">
3138
3139<h5>Syntax:</h5>
3140<pre>
3141 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3142</pre>
3143
3144<h5>Overview:</h5>
3145<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3146<tt>ty2</tt>.</p>
3147
3148
3149<h5>Arguments:</h5>
3150<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]3151<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3152also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3153<tt>value</tt> must be smaller than the bit size of the destination type,
3154<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3155
3156<h5>Semantics:</h5>
3157<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]3158bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3159
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3160<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]3161
3162<h5>Example:</h5>
3163<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3164 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3165 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3166</pre>
3167</div>
3168
3169<!-- _______________________________________________________________________ -->
3170<div class="doc_subsubsection">
3171 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3172</div>
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
3177 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3178</pre>
3179
3180<h5>Overview:</h5>
3181<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3182
3183<h5>Arguments:</h5>
3184<p>
3185The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3186<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3187also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3188<tt>value</tt> must be smaller than the bit size of the destination type,
3189<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3190
3191<h5>Semantics:</h5>
3192<p>
3193The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3194bit (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]3195the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3196
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3197<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]3198
3199<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3200<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3201 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3202 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3203</pre>
3204</div>
3205
3206<!-- _______________________________________________________________________ -->
3207<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3208 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3209</div>
3210
3211<div class="doc_text">
3212
3213<h5>Syntax:</h5>
3214
3215<pre>
3216 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3217</pre>
3218
3219<h5>Overview:</h5>
3220<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3221<tt>ty2</tt>.</p>
3222
3223
3224<h5>Arguments:</h5>
3225<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3226 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3227cast it to. The size of <tt>value</tt> must be larger than the size of
3228<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3229<i>no-op cast</i>.</p>
3230
3231<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3232<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3233<a href="#t_floating">floating point</a> type to a smaller
3234<a href="#t_floating">floating point</a> type. If the value cannot fit within
3235the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3236
3237<h5>Example:</h5>
3238<pre>
3239 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3240 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3241</pre>
3242</div>
3243
3244<!-- _______________________________________________________________________ -->
3245<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3246 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3247</div>
3248<div class="doc_text">
3249
3250<h5>Syntax:</h5>
3251<pre>
3252 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3253</pre>
3254
3255<h5>Overview:</h5>
3256<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3257floating point value.</p>
3258
3259<h5>Arguments:</h5>
3260<p>The '<tt>fpext</tt>' instruction takes a
3261<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3262and a <a href="#t_floating">floating point</a> type to cast it to. The source
3263type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3264
3265<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3266<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3267<a href="#t_floating">floating point</a> type to a larger
3268<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3269used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3270<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]3271
3272<h5>Example:</h5>
3273<pre>
3274 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3275 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3276</pre>
3277</div>
3278
3279<!-- _______________________________________________________________________ -->
3280<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3281 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3282</div>
3283<div class="doc_text">
3284
3285<h5>Syntax:</h5>
3286<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3287 &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]3288</pre>
3289
3290<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3291<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3292unsigned integer equivalent of type <tt>ty2</tt>.
3293</p>
3294
3295<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3296<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]3297scalar or vector <a href="#t_floating">floating point</a> value, and a type
3298to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3299type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3300vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3301
3302<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3303<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3304<a href="#t_floating">floating point</a> operand into the nearest (rounding
3305towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3306the results are undefined.</p>
3307
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3308<h5>Example:</h5>
3309<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3310 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3311 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3312 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3313</pre>
3314</div>
3315
3316<!-- _______________________________________________________________________ -->
3317<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3318 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3319</div>
3320<div class="doc_text">
3321
3322<h5>Syntax:</h5>
3323<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3324 &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]3325</pre>
3326
3327<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3328<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3329<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]3330</p>
3331
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3332<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3333<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]3334scalar or vector <a href="#t_floating">floating point</a> value, and a type
3335to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3336type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3337vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3338
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3339<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3340<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3341<a href="#t_floating">floating point</a> operand into the nearest (rounding
3342towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3343the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3344
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3345<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3346<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3347 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3348 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3349 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3350</pre>
3351</div>
3352
3353<!-- _______________________________________________________________________ -->
3354<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3355 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3356</div>
3357<div class="doc_text">
3358
3359<h5>Syntax:</h5>
3360<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3361 &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]3362</pre>
3363
3364<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3365<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3366integer and converts that value to the <tt>ty2</tt> type.</p>
3367
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3368<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3369<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3370scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3371to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3372type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3373floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3374
3375<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3376<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3377integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3378the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3379
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3380<h5>Example:</h5>
3381<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3382 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3383 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3384</pre>
3385</div>
3386
3387<!-- _______________________________________________________________________ -->
3388<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3389 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3390</div>
3391<div class="doc_text">
3392
3393<h5>Syntax:</h5>
3394<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3395 &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]3396</pre>
3397
3398<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3399<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3400integer and converts that value to the <tt>ty2</tt> type.</p>
3401
3402<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3403<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3404scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3405to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3406type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3407floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3408
3409<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3410<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3411integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3412the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3413
3414<h5>Example:</h5>
3415<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3416 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3417 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3418</pre>
3419</div>
3420
3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3423 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3424</div>
3425<div class="doc_text">
3426
3427<h5>Syntax:</h5>
3428<pre>
3429 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3430</pre>
3431
3432<h5>Overview:</h5>
3433<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3434the integer type <tt>ty2</tt>.</p>
3435
3436<h5>Arguments:</h5>
3437<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3438must 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]3439<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3440
3441<h5>Semantics:</h5>
3442<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3443<tt>ty2</tt> by interpreting the pointer value as an integer and either
3444truncating or zero extending that value to the size of the integer type. If
3445<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3446<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]3447are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3448change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3449
3450<h5>Example:</h5>
3451<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3452 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3453 %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]3454</pre>
3455</div>
3456
3457<!-- _______________________________________________________________________ -->
3458<div class="doc_subsubsection">
3459 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3460</div>
3461<div class="doc_text">
3462
3463<h5>Syntax:</h5>
3464<pre>
3465 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3466</pre>
3467
3468<h5>Overview:</h5>
3469<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3470a pointer type, <tt>ty2</tt>.</p>
3471
3472<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3473<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3474value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3475<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3476
3477<h5>Semantics:</h5>
3478<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3479<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3480the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3481size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3482the size of a pointer then a zero extension is done. If they are the same size,
3483nothing is done (<i>no-op cast</i>).</p>
3484
3485<h5>Example:</h5>
3486<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3487 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3488 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3489 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3490</pre>
3491</div>
3492
3493<!-- _______________________________________________________________________ -->
3494<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3495 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3496</div>
3497<div class="doc_text">
3498
3499<h5>Syntax:</h5>
3500<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3501 &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]3502</pre>
3503
3504<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3505<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3506<tt>ty2</tt> without changing any bits.</p>
3507
3508<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3509<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3510a first class value, and a type to cast it to, which must also be a <a
3511 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3512and the destination type, <tt>ty2</tt>, must be identical. If the source
3513type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3514
3515<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3516<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3517<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3518this conversion. The conversion is done as if the <tt>value</tt> had been
3519stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3520converted to other pointer types with this instruction. To convert pointers to
3521other types, use the <a href="#i_inttoptr">inttoptr</a> or
3522<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3523
3524<h5>Example:</h5>
3525<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3526 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3527 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3528 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3529</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3530</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3531
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3532<!-- ======================================================================= -->
3533<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3534<div class="doc_text">
3535<p>The instructions in this category are the "miscellaneous"
3536instructions, which defy better classification.</p>
3537</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3538
3539<!-- _______________________________________________________________________ -->
3540<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3541</div>
3542<div class="doc_text">
3543<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3544<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]3545</pre>
3546<h5>Overview:</h5>
3547<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3548of its two integer operands.</p>
3549<h5>Arguments:</h5>
3550<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3551the condition code indicating the kind of comparison to perform. It is not
3552a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3553<ol>
3554 <li><tt>eq</tt>: equal</li>
3555 <li><tt>ne</tt>: not equal </li>
3556 <li><tt>ugt</tt>: unsigned greater than</li>
3557 <li><tt>uge</tt>: unsigned greater or equal</li>
3558 <li><tt>ult</tt>: unsigned less than</li>
3559 <li><tt>ule</tt>: unsigned less or equal</li>
3560 <li><tt>sgt</tt>: signed greater than</li>
3561 <li><tt>sge</tt>: signed greater or equal</li>
3562 <li><tt>slt</tt>: signed less than</li>
3563 <li><tt>sle</tt>: signed less or equal</li>
3564</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3565<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3566<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3567<h5>Semantics:</h5>
3568<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3569the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3570yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3571<ol>
3572 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3573 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3574 </li>
3575 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3576 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3577 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3578 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3579 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3580 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3581 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3582 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3583 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3584 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3585 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3586 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3587 <li><tt>sge</tt>: interprets the operands as signed values and yields
3588 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3589 <li><tt>slt</tt>: interprets the operands as signed values and yields
3590 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3591 <li><tt>sle</tt>: interprets the operands as signed values and yields
3592 <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]3593</ol>
3594<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3595values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3596
3597<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3598<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3599 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3600 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3601 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3602 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3603 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3604</pre>
3605</div>
3606
3607<!-- _______________________________________________________________________ -->
3608<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3609</div>
3610<div class="doc_text">
3611<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3612<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]3613</pre>
3614<h5>Overview:</h5>
3615<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3616of its floating point operands.</p>
3617<h5>Arguments:</h5>
3618<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3619the condition code indicating the kind of comparison to perform. It is not
3620a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3621<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3622 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3623 <li><tt>oeq</tt>: ordered and equal</li>
3624 <li><tt>ogt</tt>: ordered and greater than </li>
3625 <li><tt>oge</tt>: ordered and greater than or equal</li>
3626 <li><tt>olt</tt>: ordered and less than </li>
3627 <li><tt>ole</tt>: ordered and less than or equal</li>
3628 <li><tt>one</tt>: ordered and not equal</li>
3629 <li><tt>ord</tt>: ordered (no nans)</li>
3630 <li><tt>ueq</tt>: unordered or equal</li>
3631 <li><tt>ugt</tt>: unordered or greater than </li>
3632 <li><tt>uge</tt>: unordered or greater than or equal</li>
3633 <li><tt>ult</tt>: unordered or less than </li>
3634 <li><tt>ule</tt>: unordered or less than or equal</li>
3635 <li><tt>une</tt>: unordered or not equal</li>
3636 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3637 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3638</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3639<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3640<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3641<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3642<a href="#t_floating">floating point</a> typed. They must have identical
3643types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3644<h5>Semantics:</h5>
3645<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3646the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3647yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3648<ol>
3649 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3650 <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]3651 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3652 <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]3653 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3654 <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]3655 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3656 <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]3657 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3658 <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]3659 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3660 <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]3661 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3662 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3663 <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]3664 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3665 <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]3666 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3667 <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]3668 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3669 <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]3670 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3671 <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]3672 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3673 <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]3674 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3675 <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]3676 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3677</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3678
3679<h5>Example:</h5>
3680<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3681 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3682 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3683 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3684</pre>
3685</div>
3686
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3687<!-- _______________________________________________________________________ -->
3688<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3689Instruction</a> </div>
3690<div class="doc_text">
3691<h5>Syntax:</h5>
3692<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3693<h5>Overview:</h5>
3694<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3695the SSA graph representing the function.</p>
3696<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3697<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3698field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3699as arguments, with one pair for each predecessor basic block of the
3700current block. Only values of <a href="#t_firstclass">first class</a>
3701type may be used as the value arguments to the PHI node. Only labels
3702may be used as the label arguments.</p>
3703<p>There must be no non-phi instructions between the start of a basic
3704block and the PHI instructions: i.e. PHI instructions must be first in
3705a basic block.</p>
3706<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3707<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3708specified by the pair corresponding to the predecessor basic block that executed
3709just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3710<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3711<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3712</div>
3713
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection">
3716 <a name="i_select">'<tt>select</tt>' Instruction</a>
3717</div>
3718
3719<div class="doc_text">
3720
3721<h5>Syntax:</h5>
3722
3723<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3724 &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]3725</pre>
3726
3727<h5>Overview:</h5>
3728
3729<p>
3730The '<tt>select</tt>' instruction is used to choose one value based on a
3731condition, without branching.
3732</p>
3733
3734
3735<h5>Arguments:</h5>
3736
3737<p>
3738The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
3739</p>
3740
3741<h5>Semantics:</h5>
3742
3743<p>
3744If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3745value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3746</p>
3747
3748<h5>Example:</h5>
3749
3750<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3751 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3752</pre>
3753</div>
3754
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3755
3756<!-- _______________________________________________________________________ -->
3757<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3758 <a name="i_call">'<tt>call</tt>' Instruction</a>
3759</div>
3760
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3761<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3762
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3763<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3764<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3765 &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]3766</pre>
3767
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3768<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3769
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3770<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3771
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3772<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3773
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3774<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3775
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3776<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3777 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3778 <p>The optional "tail" marker indicates whether the callee function accesses
3779 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3780 function call is eligible for tail call optimization. Note that calls may
3781 be marked "tail" even if they do not occur before a <a
3782 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3783 </li>
3784 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3785 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3786 convention</a> the call should use. If none is specified, the call defaults
3787 to using C calling conventions.
3788 </li>
3789 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3790 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3791 the type of the return value. Functions that return no value are marked
3792 <tt><a href="#t_void">void</a></tt>.</p>
3793 </li>
3794 <li>
3795 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3796 value being invoked. The argument types must match the types implied by
3797 this signature. This type can be omitted if the function is not varargs
3798 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3799 </li>
3800 <li>
3801 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3802 be invoked. In most cases, this is a direct function invocation, but
3803 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3804 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3805 </li>
3806 <li>
3807 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3808 function signature argument types. All arguments must be of
3809 <a href="#t_firstclass">first class</a> type. If the function signature
3810 indicates the function accepts a variable number of arguments, the extra
3811 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3812 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3813</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3814
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3815<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3816
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3817<p>The '<tt>call</tt>' instruction is used to cause control flow to
3818transfer to a specified function, with its incoming arguments bound to
3819the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3820instruction in the called function, control flow continues with the
3821instruction after the function call, and the return value of the
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3822function is bound to the result argument. If the '<tt><a href="#i_ret">ret</a>
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]3823</tt>' instruction returns multiple values then the return values of the
3824function are only accessible through a '<tt><a href="#i_getresult">getresult</a>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3825</tt>' instruction. This is a simpler case of
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3826the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3827
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3828<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3829
3830<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3831 %retval = call i32 @test(i32 %argc)
3832 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3833 %X = tail call i32 @foo()
3834 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3835 %Z = call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3836
3837 %struct.A = type { i32, i8 }
3838 %r = call %struct.A @foo()
3839 %gr = getresult %struct.A %r, 0
3840 %gr1 = getresult %struct.A %r, 1
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3841</pre>
3842
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3843</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3844
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3845<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3846<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3847 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3848</div>
3849
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3850<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3851
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3852<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3853
3854<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3855 &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]3856</pre>
3857
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3858<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3859
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3860<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3861the "variable argument" area of a function call. It is used to implement the
3862<tt>va_arg</tt> macro in C.</p>
3863
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3864<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3865
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3866<p>This instruction takes a <tt>va_list*</tt> value and the type of
3867the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3868increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3869actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3870
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3871<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3872
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3873<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3874type from the specified <tt>va_list</tt> and causes the
3875<tt>va_list</tt> to point to the next argument. For more information,
3876see the variable argument handling <a href="#int_varargs">Intrinsic
3877Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3878
3879<p>It is legal for this instruction to be called in a function which does not
3880take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3881function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3882
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3883<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3884href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3885argument.</p>
3886
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3887<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3888
3889<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3890
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3891</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3892
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3893<!-- _______________________________________________________________________ -->
3894<div class="doc_subsubsection">
3895 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3896</div>
3897
3898<div class="doc_text">
3899
3900<h5>Syntax:</h5>
3901<pre>
3902 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
3903</pre>
3904<h5>Overview:</h5>
3905
3906<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]3907from multiple values returned by a '<tt><a href="#i_call">call</a></tt>'
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3908or '<tt><a href="#i_invoke">invoke</a></tt>' instruction.
3909
3910<h5>Arguments:</h5>
3911
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]3912The '<tt>getresult</tt>' instruction takes a return value as first argument.
3913The value must have <a href="#t_struct">structure type</a>. The second argument
3914is an unsigned index value.
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3915
3916<h5>Semantics:</h5>
3917
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]3918The '<tt>getresult</tt>' instruction extracts the element identified by
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3919'<tt>index</tt>' from the aggregate value.
3920
3921<h5>Example:</h5>
3922
3923<pre>
3924 %struct.A = type { i32, i8 }
3925
3926 %r = call %struct.A @foo()
3927 %gr = getresult %struct.A %r, 0
3928 %gr1 = getresult %struct.A %r, 1
3929 add i32 %gr, 42
3930 add i8 %gr1, 41
3931</pre>
3932
3933</div>
3934
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3935<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3936<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3937<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3938
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3939<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3940
3941<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3942well known names and semantics and are required to follow certain restrictions.
3943Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3944language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]3945adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3946
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3947<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3948prefix is reserved in LLVM for intrinsic names; thus, function names may not
3949begin with this prefix. Intrinsic functions must always be external functions:
3950you cannot define the body of intrinsic functions. Intrinsic functions may
3951only be used in call or invoke instructions: it is illegal to take the address
3952of an intrinsic function. Additionally, because intrinsic functions are part
3953of the LLVM language, it is required if any are added that they be documented
3954here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3955
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3956<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3957a family of functions that perform the same operation but on different data
3958types. Because LLVM can represent over 8 million different integer types,
3959overloading is used commonly to allow an intrinsic function to operate on any
3960integer type. One or more of the argument types or the result type can be
3961overloaded to accept any integer type. Argument types may also be defined as
3962exactly matching a previous argument's type or the result type. This allows an
3963intrinsic function which accepts multiple arguments, but needs all of them to
3964be of the same type, to only be overloaded with respect to a single argument or
3965the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3966
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3967<p>Overloaded intrinsics will have the names of its overloaded argument types
3968encoded into its function name, each preceded by a period. Only those types
3969which are overloaded result in a name suffix. Arguments whose type is matched
3970against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3971take an integer of any width and returns an integer of exactly the same integer
3972width. This leads to a family of functions such as
3973<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3974Only one type, the return type, is overloaded, and only one type suffix is
3975required. Because the argument's type is matched against the return type, it
3976does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3977
3978<p>To learn how to add an intrinsic function, please see the
3979<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3980</p>
3981
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3982</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3983
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3984<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3985<div class="doc_subsection">
3986 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3987</div>
3988
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3989<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3990
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3991<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3992 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3993intrinsic functions. These functions are related to the similarly
3994named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3995
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3996<p>All of these functions operate on arguments that use a
3997target-specific value type "<tt>va_list</tt>". The LLVM assembly
3998language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3999transformations should be prepared to handle these functions regardless of
4000the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4001
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]4002<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]4003instruction and the variable argument handling intrinsic functions are
4004used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4005
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4006<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4007<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4008define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4009 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4010 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4011 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4012 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4013
4014 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4015 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4016
4017 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4018 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4019 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4020 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4021 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4022
4023 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4024 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4025 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4026}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4027
4028declare void @llvm.va_start(i8*)
4029declare void @llvm.va_copy(i8*, i8*)
4030declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4031</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4032</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4033
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4034</div>
4035
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4036<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4037<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4038 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4039</div>
4040
4041
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4042<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4043<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4044<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4045<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4046<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4047<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4048href="#i_va_arg">va_arg</a></tt>.</p>
4049
4050<h5>Arguments:</h5>
4051
4052<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4053
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4054<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4055
4056<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4057macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4058<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]4059<tt>va_arg</tt> will produce the first variable argument passed to the function.
4060Unlike 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]4061last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4062
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4063</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4064
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4065<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4066<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4067 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4068</div>
4069
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4070<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4071<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4072<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4073<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4074
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4075<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4076which 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]4077or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4078
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4079<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4080
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4081<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]4082
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4083<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4084
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4085<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]4086macro available in C. In a target-dependent way, it destroys the
4087<tt>va_list</tt> element to which the argument points. Calls to <a
4088href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4089<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4090<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4091
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4092</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4093
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4094<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4095<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4096 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4097</div>
4098
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4099<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4100
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4101<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4102
4103<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4104 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4105</pre>
4106
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4107<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4108
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4109<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4110from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4111
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4112<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4113
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4114<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]4115The 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]4116
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4117
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4118<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4119
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4120<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4121macro available in C. In a target-dependent way, it copies the source
4122<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4123intrinsic is necessary because the <tt><a href="#int_va_start">
4124llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4125example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4126
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4127</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4128
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4129<!-- ======================================================================= -->
4130<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4131 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4132</div>
4133
4134<div class="doc_text">
4135
4136<p>
4137LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4138Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4139These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4140stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4141href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4142Front-ends for type-safe garbage collected languages should generate these
4143intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4144href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4145</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4146
4147<p>The garbage collection intrinsics only operate on objects in the generic
4148 address space (address space zero).</p>
4149
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4150</div>
4151
4152<!-- _______________________________________________________________________ -->
4153<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4154 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4155</div>
4156
4157<div class="doc_text">
4158
4159<h5>Syntax:</h5>
4160
4161<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4162 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4163</pre>
4164
4165<h5>Overview:</h5>
4166
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4167<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]4168the code generator, and allows some metadata to be associated with it.</p>
4169
4170<h5>Arguments:</h5>
4171
4172<p>The first argument specifies the address of a stack object that contains the
4173root pointer. The second pointer (which must be either a constant or a global
4174value address) contains the meta-data to be associated with the root.</p>
4175
4176<h5>Semantics:</h5>
4177
4178<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4179location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4180the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4181intrinsic may only be used in a function which <a href="#gc">specifies a GC
4182algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4183
4184</div>
4185
4186
4187<!-- _______________________________________________________________________ -->
4188<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4189 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4190</div>
4191
4192<div class="doc_text">
4193
4194<h5>Syntax:</h5>
4195
4196<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4197 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4198</pre>
4199
4200<h5>Overview:</h5>
4201
4202<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4203locations, allowing garbage collector implementations that require read
4204barriers.</p>
4205
4206<h5>Arguments:</h5>
4207
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4208<p>The second argument is the address to read from, which should be an address
4209allocated from the garbage collector. The first object is a pointer to the
4210start of the referenced object, if needed by the language runtime (otherwise
4211null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4212
4213<h5>Semantics:</h5>
4214
4215<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4216instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4217garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4218may only be used in a function which <a href="#gc">specifies a GC
4219algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4220
4221</div>
4222
4223
4224<!-- _______________________________________________________________________ -->
4225<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4226 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4227</div>
4228
4229<div class="doc_text">
4230
4231<h5>Syntax:</h5>
4232
4233<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4234 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4235</pre>
4236
4237<h5>Overview:</h5>
4238
4239<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4240locations, allowing garbage collector implementations that require write
4241barriers (such as generational or reference counting collectors).</p>
4242
4243<h5>Arguments:</h5>
4244
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4245<p>The first argument is the reference to store, the second is the start of the
4246object to store it to, and the third is the address of the field of Obj to
4247store to. If the runtime does not require a pointer to the object, Obj may be
4248null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4249
4250<h5>Semantics:</h5>
4251
4252<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4253instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4254garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4255may only be used in a function which <a href="#gc">specifies a GC
4256algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4257
4258</div>
4259
4260
4261
4262<!-- ======================================================================= -->
4263<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4264 <a name="int_codegen">Code Generator Intrinsics</a>
4265</div>
4266
4267<div class="doc_text">
4268<p>
4269These intrinsics are provided by LLVM to expose special features that may only
4270be implemented with code generator support.
4271</p>
4272
4273</div>
4274
4275<!-- _______________________________________________________________________ -->
4276<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4277 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4278</div>
4279
4280<div class="doc_text">
4281
4282<h5>Syntax:</h5>
4283<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4284 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4285</pre>
4286
4287<h5>Overview:</h5>
4288
4289<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4290The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4291target-specific value indicating the return address of the current function
4292or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4293</p>
4294
4295<h5>Arguments:</h5>
4296
4297<p>
4298The argument to this intrinsic indicates which function to return the address
4299for. Zero indicates the calling function, one indicates its caller, etc. The
4300argument is <b>required</b> to be a constant integer value.
4301</p>
4302
4303<h5>Semantics:</h5>
4304
4305<p>
4306The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4307the return address of the specified call frame, or zero if it cannot be
4308identified. The value returned by this intrinsic is likely to be incorrect or 0
4309for arguments other than zero, so it should only be used for debugging purposes.
4310</p>
4311
4312<p>
4313Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4314aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4315source-language caller.
4316</p>
4317</div>
4318
4319
4320<!-- _______________________________________________________________________ -->
4321<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4322 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4323</div>
4324
4325<div class="doc_text">
4326
4327<h5>Syntax:</h5>
4328<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4329 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4330</pre>
4331
4332<h5>Overview:</h5>
4333
4334<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4335The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4336target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4337</p>
4338
4339<h5>Arguments:</h5>
4340
4341<p>
4342The argument to this intrinsic indicates which function to return the frame
4343pointer for. Zero indicates the calling function, one indicates its caller,
4344etc. The argument is <b>required</b> to be a constant integer value.
4345</p>
4346
4347<h5>Semantics:</h5>
4348
4349<p>
4350The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4351the frame address of the specified call frame, or zero if it cannot be
4352identified. The value returned by this intrinsic is likely to be incorrect or 0
4353for arguments other than zero, so it should only be used for debugging purposes.
4354</p>
4355
4356<p>
4357Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4358aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4359source-language caller.
4360</p>
4361</div>
4362
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4363<!-- _______________________________________________________________________ -->
4364<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4365 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4366</div>
4367
4368<div class="doc_text">
4369
4370<h5>Syntax:</h5>
4371<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4372 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4373</pre>
4374
4375<h5>Overview:</h5>
4376
4377<p>
4378The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4379the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4380<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4381features like scoped automatic variable sized arrays in C99.
4382</p>
4383
4384<h5>Semantics:</h5>
4385
4386<p>
4387This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4388href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4389<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4390<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4391state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4392practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4393that were allocated after the <tt>llvm.stacksave</tt> was executed.
4394</p>
4395
4396</div>
4397
4398<!-- _______________________________________________________________________ -->
4399<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4400 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4401</div>
4402
4403<div class="doc_text">
4404
4405<h5>Syntax:</h5>
4406<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4407 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4408</pre>
4409
4410<h5>Overview:</h5>
4411
4412<p>
4413The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4414the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4415href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4416useful for implementing language features like scoped automatic variable sized
4417arrays in C99.
4418</p>
4419
4420<h5>Semantics:</h5>
4421
4422<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4423See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4424</p>
4425
4426</div>
4427
4428
4429<!-- _______________________________________________________________________ -->
4430<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4431 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4432</div>
4433
4434<div class="doc_text">
4435
4436<h5>Syntax:</h5>
4437<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4438 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]4439</pre>
4440
4441<h5>Overview:</h5>
4442
4443
4444<p>
4445The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4446a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4447no
4448effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4449characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4450</p>
4451
4452<h5>Arguments:</h5>
4453
4454<p>
4455<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4456determining if the fetch should be for a read (0) or write (1), and
4457<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4458locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4459<tt>locality</tt> arguments must be constant integers.
4460</p>
4461
4462<h5>Semantics:</h5>
4463
4464<p>
4465This intrinsic does not modify the behavior of the program. In particular,
4466prefetches cannot trap and do not produce a value. On targets that support this
4467intrinsic, the prefetch can provide hints to the processor cache for better
4468performance.
4469</p>
4470
4471</div>
4472
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4473<!-- _______________________________________________________________________ -->
4474<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4475 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4476</div>
4477
4478<div class="doc_text">
4479
4480<h5>Syntax:</h5>
4481<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4482 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4483</pre>
4484
4485<h5>Overview:</h5>
4486
4487
4488<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4489The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4490(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4491code to simulators and other tools. The method is target specific, but it is
4492expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4493The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4494after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4495optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4496correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4497</p>
4498
4499<h5>Arguments:</h5>
4500
4501<p>
4502<tt>id</tt> is a numerical id identifying the marker.
4503</p>
4504
4505<h5>Semantics:</h5>
4506
4507<p>
4508This intrinsic does not modify the behavior of the program. Backends that do not
4509support this intrinisic may ignore it.
4510</p>
4511
4512</div>
4513
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4514<!-- _______________________________________________________________________ -->
4515<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4516 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4517</div>
4518
4519<div class="doc_text">
4520
4521<h5>Syntax:</h5>
4522<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4523 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4524</pre>
4525
4526<h5>Overview:</h5>
4527
4528
4529<p>
4530The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4531counter register (or similar low latency, high accuracy clocks) on those targets
4532that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4533As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4534should only be used for small timings.
4535</p>
4536
4537<h5>Semantics:</h5>
4538
4539<p>
4540When directly supported, reading the cycle counter should not modify any memory.
4541Implementations are allowed to either return a application specific value or a
4542system wide value. On backends without support, this is lowered to a constant 0.
4543</p>
4544
4545</div>
4546
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4547<!-- ======================================================================= -->
4548<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4549 <a name="int_libc">Standard C Library Intrinsics</a>
4550</div>
4551
4552<div class="doc_text">
4553<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4554LLVM provides intrinsics for a few important standard C library functions.
4555These intrinsics allow source-language front-ends to pass information about the
4556alignment of the pointer arguments to the code generator, providing opportunity
4557for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4558</p>
4559
4560</div>
4561
4562<!-- _______________________________________________________________________ -->
4563<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4564 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4565</div>
4566
4567<div class="doc_text">
4568
4569<h5>Syntax:</h5>
4570<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4571 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4572 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4573 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4574 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4575</pre>
4576
4577<h5>Overview:</h5>
4578
4579<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4580The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4581location to the destination location.
4582</p>
4583
4584<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4585Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4586intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4587</p>
4588
4589<h5>Arguments:</h5>
4590
4591<p>
4592The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4593the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4594specifying the number of bytes to copy, and the fourth argument is the alignment
4595of the source and destination locations.
4596</p>
4597
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4598<p>
4599If 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]4600the caller guarantees that both the source and destination pointers are aligned
4601to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4602</p>
4603
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4604<h5>Semantics:</h5>
4605
4606<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4607The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4608location to the destination location, which are not allowed to overlap. It
4609copies "len" bytes of memory over. If the argument is known to be aligned to
4610some boundary, this can be specified as the fourth argument, otherwise it should
4611be set to 0 or 1.
4612</p>
4613</div>
4614
4615
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4616<!-- _______________________________________________________________________ -->
4617<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4618 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4619</div>
4620
4621<div class="doc_text">
4622
4623<h5>Syntax:</h5>
4624<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4625 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4626 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4627 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4628 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4629</pre>
4630
4631<h5>Overview:</h5>
4632
4633<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4634The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4635location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]4636'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4637</p>
4638
4639<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4640Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4641intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4642</p>
4643
4644<h5>Arguments:</h5>
4645
4646<p>
4647The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4648the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4649specifying the number of bytes to copy, and the fourth argument is the alignment
4650of the source and destination locations.
4651</p>
4652
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4653<p>
4654If 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]4655the caller guarantees that the source and destination pointers are aligned to
4656that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4657</p>
4658
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4659<h5>Semantics:</h5>
4660
4661<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4662The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4663location to the destination location, which may overlap. It
4664copies "len" bytes of memory over. If the argument is known to be aligned to
4665some boundary, this can be specified as the fourth argument, otherwise it should
4666be set to 0 or 1.
4667</p>
4668</div>
4669
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4670
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4671<!-- _______________________________________________________________________ -->
4672<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4673 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4674</div>
4675
4676<div class="doc_text">
4677
4678<h5>Syntax:</h5>
4679<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4680 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4681 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4682 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4683 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4684</pre>
4685
4686<h5>Overview:</h5>
4687
4688<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4689The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4690byte value.
4691</p>
4692
4693<p>
4694Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4695does not return a value, and takes an extra alignment argument.
4696</p>
4697
4698<h5>Arguments:</h5>
4699
4700<p>
4701The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4702byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4703argument specifying the number of bytes to fill, and the fourth argument is the
4704known alignment of destination location.
4705</p>
4706
4707<p>
4708If 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]4709the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4710</p>
4711
4712<h5>Semantics:</h5>
4713
4714<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4715The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4716the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4717destination location. If the argument is known to be aligned to some boundary,
4718this can be specified as the fourth argument, otherwise it should be set to 0 or
47191.
4720</p>
4721</div>
4722
4723
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4724<!-- _______________________________________________________________________ -->
4725<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4726 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4727</div>
4728
4729<div class="doc_text">
4730
4731<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4732<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]4733floating point or vector of floating point type. Not all targets support all
4734types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4735<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4736 declare float @llvm.sqrt.f32(float %Val)
4737 declare double @llvm.sqrt.f64(double %Val)
4738 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4739 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4740 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4741</pre>
4742
4743<h5>Overview:</h5>
4744
4745<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4746The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4747returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4748<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +0000[diff] [blame]4749negative numbers other than -0.0 (which allows for better optimization, because
4750there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4751defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4752</p>
4753
4754<h5>Arguments:</h5>
4755
4756<p>
4757The argument and return value are floating point numbers of the same type.
4758</p>
4759
4760<h5>Semantics:</h5>
4761
4762<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]4763This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4764floating point number.
4765</p>
4766</div>
4767
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4768<!-- _______________________________________________________________________ -->
4769<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4770 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4771</div>
4772
4773<div class="doc_text">
4774
4775<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4776<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]4777floating point or vector of floating point type. Not all targets support all
4778types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4779<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4780 declare float @llvm.powi.f32(float %Val, i32 %power)
4781 declare double @llvm.powi.f64(double %Val, i32 %power)
4782 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4783 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4784 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4785</pre>
4786
4787<h5>Overview:</h5>
4788
4789<p>
4790The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4791specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4792multiplications is not defined. When a vector of floating point type is
4793used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4794</p>
4795
4796<h5>Arguments:</h5>
4797
4798<p>
4799The second argument is an integer power, and the first is a value to raise to
4800that power.
4801</p>
4802
4803<h5>Semantics:</h5>
4804
4805<p>
4806This function returns the first value raised to the second power with an
4807unspecified sequence of rounding operations.</p>
4808</div>
4809
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4810<!-- _______________________________________________________________________ -->
4811<div class="doc_subsubsection">
4812 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4813</div>
4814
4815<div class="doc_text">
4816
4817<h5>Syntax:</h5>
4818<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4819floating point or vector of floating point type. Not all targets support all
4820types however.
4821<pre>
4822 declare float @llvm.sin.f32(float %Val)
4823 declare double @llvm.sin.f64(double %Val)
4824 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4825 declare fp128 @llvm.sin.f128(fp128 %Val)
4826 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4827</pre>
4828
4829<h5>Overview:</h5>
4830
4831<p>
4832The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4833</p>
4834
4835<h5>Arguments:</h5>
4836
4837<p>
4838The argument and return value are floating point numbers of the same type.
4839</p>
4840
4841<h5>Semantics:</h5>
4842
4843<p>
4844This function returns the sine of the specified operand, returning the
4845same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4846conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4847</div>
4848
4849<!-- _______________________________________________________________________ -->
4850<div class="doc_subsubsection">
4851 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4852</div>
4853
4854<div class="doc_text">
4855
4856<h5>Syntax:</h5>
4857<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4858floating point or vector of floating point type. Not all targets support all
4859types however.
4860<pre>
4861 declare float @llvm.cos.f32(float %Val)
4862 declare double @llvm.cos.f64(double %Val)
4863 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4864 declare fp128 @llvm.cos.f128(fp128 %Val)
4865 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4866</pre>
4867
4868<h5>Overview:</h5>
4869
4870<p>
4871The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4872</p>
4873
4874<h5>Arguments:</h5>
4875
4876<p>
4877The argument and return value are floating point numbers of the same type.
4878</p>
4879
4880<h5>Semantics:</h5>
4881
4882<p>
4883This function returns the cosine of the specified operand, returning the
4884same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4885conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4886</div>
4887
4888<!-- _______________________________________________________________________ -->
4889<div class="doc_subsubsection">
4890 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4891</div>
4892
4893<div class="doc_text">
4894
4895<h5>Syntax:</h5>
4896<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4897floating point or vector of floating point type. Not all targets support all
4898types however.
4899<pre>
4900 declare float @llvm.pow.f32(float %Val, float %Power)
4901 declare double @llvm.pow.f64(double %Val, double %Power)
4902 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4903 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4904 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4905</pre>
4906
4907<h5>Overview:</h5>
4908
4909<p>
4910The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4911specified (positive or negative) power.
4912</p>
4913
4914<h5>Arguments:</h5>
4915
4916<p>
4917The second argument is a floating point power, and the first is a value to
4918raise to that power.
4919</p>
4920
4921<h5>Semantics:</h5>
4922
4923<p>
4924This function returns the first value raised to the second power,
4925returning the
4926same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4927conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4928</div>
4929
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4930
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4931<!-- ======================================================================= -->
4932<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4933 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4934</div>
4935
4936<div class="doc_text">
4937<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4938LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4939These allow efficient code generation for some algorithms.
4940</p>
4941
4942</div>
4943
4944<!-- _______________________________________________________________________ -->
4945<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4946 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4947</div>
4948
4949<div class="doc_text">
4950
4951<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4952<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4953type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4954<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4955 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4956 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4957 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4958</pre>
4959
4960<h5>Overview:</h5>
4961
4962<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4963The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4964values with an even number of bytes (positive multiple of 16 bits). These are
4965useful for performing operations on data that is not in the target's native
4966byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4967</p>
4968
4969<h5>Semantics:</h5>
4970
4971<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4972The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4973and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4974intrinsic returns an i32 value that has the four bytes of the input i32
4975swapped, 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]4976i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4977<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4978additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4979</p>
4980
4981</div>
4982
4983<!-- _______________________________________________________________________ -->
4984<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4985 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4986</div>
4987
4988<div class="doc_text">
4989
4990<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4991<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4992width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4993<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4994 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4995 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4996 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4997 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4998 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4999</pre>
5000
5001<h5>Overview:</h5>
5002
5003<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]5004The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5005value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5006</p>
5007
5008<h5>Arguments:</h5>
5009
5010<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5011The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5012integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5013</p>
5014
5015<h5>Semantics:</h5>
5016
5017<p>
5018The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5019</p>
5020</div>
5021
5022<!-- _______________________________________________________________________ -->
5023<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5024 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5025</div>
5026
5027<div class="doc_text">
5028
5029<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5030<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5031integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5032<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5033 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5034 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5035 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5036 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5037 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5038</pre>
5039
5040<h5>Overview:</h5>
5041
5042<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5043The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5044leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5045</p>
5046
5047<h5>Arguments:</h5>
5048
5049<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5050The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5051integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5052</p>
5053
5054<h5>Semantics:</h5>
5055
5056<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5057The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5058in 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]5059of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5060</p>
5061</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5062
5063
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5064
5065<!-- _______________________________________________________________________ -->
5066<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5067 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5068</div>
5069
5070<div class="doc_text">
5071
5072<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5073<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5074integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5075<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5076 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5077 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5078 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5079 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5080 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5081</pre>
5082
5083<h5>Overview:</h5>
5084
5085<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5086The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5087trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5088</p>
5089
5090<h5>Arguments:</h5>
5091
5092<p>
5093The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5094integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5095</p>
5096
5097<h5>Semantics:</h5>
5098
5099<p>
5100The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5101in a variable. If the src == 0 then the result is the size in bits of the type
5102of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5103</p>
5104</div>
5105
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5106<!-- _______________________________________________________________________ -->
5107<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5108 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5109</div>
5110
5111<div class="doc_text">
5112
5113<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5114<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5115on any integer bit width.
5116<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5117 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5118 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5119</pre>
5120
5121<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5122<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5123range of bits from an integer value and returns them in the same bit width as
5124the original value.</p>
5125
5126<h5>Arguments:</h5>
5127<p>The first argument, <tt>%val</tt> and the result may be integer types of
5128any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5129arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5130
5131<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5132<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5133of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5134<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5135operates in forward mode.</p>
5136<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5137right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5138only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5139<ol>
5140 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5141 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5142 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5143 to determine the number of bits to retain.</li>
5144 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5145 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5146</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5147<p>In reverse mode, a similar computation is made except that the bits are
5148returned in the reverse order. So, for example, if <tt>X</tt> has the value
5149<tt>i16 0x0ACF (101011001111)</tt> and we apply
5150<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5151<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5152</div>
5153
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5154<div class="doc_subsubsection">
5155 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5156</div>
5157
5158<div class="doc_text">
5159
5160<h5>Syntax:</h5>
5161<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5162on any integer bit width.
5163<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5164 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5165 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]5166</pre>
5167
5168<h5>Overview:</h5>
5169<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5170of bits in an integer value with another integer value. It returns the integer
5171with the replaced bits.</p>
5172
5173<h5>Arguments:</h5>
5174<p>The first argument, <tt>%val</tt> and the result may be integer types of
5175any bit width but they must have the same bit width. <tt>%val</tt> is the value
5176whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5177integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5178type since they specify only a bit index.</p>
5179
5180<h5>Semantics:</h5>
5181<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5182of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5183<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5184operates in forward mode.</p>
5185<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5186truncating it down to the size of the replacement area or zero extending it
5187up to that size.</p>
5188<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5189are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5190in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5191to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5192<p>In reverse mode, a similar computation is made except that the bits are
5193reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5194<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]5195<h5>Examples:</h5>
5196<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5197 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5198 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5199 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5200 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5201 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5202</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5203</div>
5204
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5205<!-- ======================================================================= -->
5206<div class="doc_subsection">
5207 <a name="int_debugger">Debugger Intrinsics</a>
5208</div>
5209
5210<div class="doc_text">
5211<p>
5212The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5213are described in the <a
5214href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5215Debugging</a> document.
5216</p>
5217</div>
5218
5219
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5220<!-- ======================================================================= -->
5221<div class="doc_subsection">
5222 <a name="int_eh">Exception Handling Intrinsics</a>
5223</div>
5224
5225<div class="doc_text">
5226<p> The LLVM exception handling intrinsics (which all start with
5227<tt>llvm.eh.</tt> prefix), are described in the <a
5228href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5229Handling</a> document. </p>
5230</div>
5231
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5232<!-- ======================================================================= -->
5233<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5234 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5235</div>
5236
5237<div class="doc_text">
5238<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5239 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5240 the <tt>nest</tt> attribute, from a function. The result is a callable
5241 function pointer lacking the nest parameter - the caller does not need
5242 to provide a value for it. Instead, the value to use is stored in
5243 advance in a "trampoline", a block of memory usually allocated
5244 on the stack, which also contains code to splice the nest value into the
5245 argument list. This is used to implement the GCC nested function address
5246 extension.
5247</p>
5248<p>
5249 For example, if the function is
5250 <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]5251 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]5252<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5253 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5254 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5255 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5256 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5257</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5258 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5259 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5260</div>
5261
5262<!-- _______________________________________________________________________ -->
5263<div class="doc_subsubsection">
5264 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5265</div>
5266<div class="doc_text">
5267<h5>Syntax:</h5>
5268<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5269declare 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]5270</pre>
5271<h5>Overview:</h5>
5272<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5273 This fills the memory pointed to by <tt>tramp</tt> with code
5274 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5275</p>
5276<h5>Arguments:</h5>
5277<p>
5278 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5279 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5280 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5281 intrinsic. Note that the size and the alignment are target-specific - LLVM
5282 currently provides no portable way of determining them, so a front-end that
5283 generates this intrinsic needs to have some target-specific knowledge.
5284 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]5285</p>
5286<h5>Semantics:</h5>
5287<p>
5288 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5289 dependent code, turning it into a function. A pointer to this function is
5290 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5291 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5292 before being called. The new function's signature is the same as that of
5293 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5294 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5295 of pointer type. Calling the new function is equivalent to calling
5296 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5297 missing <tt>nest</tt> argument. If, after calling
5298 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5299 modified, then the effect of any later call to the returned function pointer is
5300 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5301</p>
5302</div>
5303
5304<!-- ======================================================================= -->
5305<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5306 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5307</div>
5308
5309<div class="doc_text">
5310<p>
5311 These intrinsic functions expand the "universal IR" of LLVM to represent
5312 hardware constructs for atomic operations and memory synchronization. This
5313 provides an interface to the hardware, not an interface to the programmer. It
5314 is aimed at a low enough level to allow any programming models or APIs which
5315 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5316 hardware behavior. Just as hardware provides a "universal IR" for source
5317 languages, it also provides a starting point for developing a "universal"
5318 atomic operation and synchronization IR.
5319</p>
5320<p>
5321 These do <em>not</em> form an API such as high-level threading libraries,
5322 software transaction memory systems, atomic primitives, and intrinsic
5323 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5324 application libraries. The hardware interface provided by LLVM should allow
5325 a clean implementation of all of these APIs and parallel programming models.
5326 No one model or paradigm should be selected above others unless the hardware
5327 itself ubiquitously does so.
5328
5329</p>
5330</div>
5331
5332<!-- _______________________________________________________________________ -->
5333<div class="doc_subsubsection">
5334 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5335</div>
5336<div class="doc_text">
5337<h5>Syntax:</h5>
5338<pre>
5339declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5340i1 &lt;device&gt; )
5341
5342</pre>
5343<h5>Overview:</h5>
5344<p>
5345 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5346 specific pairs of memory access types.
5347</p>
5348<h5>Arguments:</h5>
5349<p>
5350 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5351 The first four arguments enables a specific barrier as listed below. The fith
5352 argument specifies that the barrier applies to io or device or uncached memory.
5353
5354</p>
5355 <ul>
5356 <li><tt>ll</tt>: load-load barrier</li>
5357 <li><tt>ls</tt>: load-store barrier</li>
5358 <li><tt>sl</tt>: store-load barrier</li>
5359 <li><tt>ss</tt>: store-store barrier</li>
5360 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5361 </ul>
5362<h5>Semantics:</h5>
5363<p>
5364 This intrinsic causes the system to enforce some ordering constraints upon
5365 the loads and stores of the program. This barrier does not indicate
5366 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5367 which they occur. For any of the specified pairs of load and store operations
5368 (f.ex. load-load, or store-load), all of the first operations preceding the
5369 barrier will complete before any of the second operations succeeding the
5370 barrier begin. Specifically the semantics for each pairing is as follows:
5371</p>
5372 <ul>
5373 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5374 after the barrier begins.</li>
5375
5376 <li><tt>ls</tt>: All loads before the barrier must complete before any
5377 store after the barrier begins.</li>
5378 <li><tt>ss</tt>: All stores before the barrier must complete before any
5379 store after the barrier begins.</li>
5380 <li><tt>sl</tt>: All stores before the barrier must complete before any
5381 load after the barrier begins.</li>
5382 </ul>
5383<p>
5384 These semantics are applied with a logical "and" behavior when more than one
5385 is enabled in a single memory barrier intrinsic.
5386</p>
5387<p>
5388 Backends may implement stronger barriers than those requested when they do not
5389 support as fine grained a barrier as requested. Some architectures do not
5390 need all types of barriers and on such architectures, these become noops.
5391</p>
5392<h5>Example:</h5>
5393<pre>
5394%ptr = malloc i32
5395 store i32 4, %ptr
5396
5397%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5398 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5399 <i>; guarantee the above finishes</i>
5400 store i32 8, %ptr <i>; before this begins</i>
5401</pre>
5402</div>
5403
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]5404<!-- _______________________________________________________________________ -->
5405<div class="doc_subsubsection">
5406 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5407</div>
5408<div class="doc_text">
5409<h5>Syntax:</h5>
5410<p>
5411 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5412 integer bit width. Not all targets support all bit widths however.</p>
5413
5414<pre>
5415declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5416declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5417declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5418declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5419
5420</pre>
5421<h5>Overview:</h5>
5422<p>
5423 This loads a value in memory and compares it to a given value. If they are
5424 equal, it stores a new value into the memory.
5425</p>
5426<h5>Arguments:</h5>
5427<p>
5428 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5429 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5430 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5431 this integer type. While any bit width integer may be used, targets may only
5432 lower representations they support in hardware.
5433
5434</p>
5435<h5>Semantics:</h5>
5436<p>
5437 This entire intrinsic must be executed atomically. It first loads the value
5438 in memory pointed to by <tt>ptr</tt> and compares it with the value
5439 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5440 loaded value is yielded in all cases. This provides the equivalent of an
5441 atomic compare-and-swap operation within the SSA framework.
5442</p>
5443<h5>Examples:</h5>
5444
5445<pre>
5446%ptr = malloc i32
5447 store i32 4, %ptr
5448
5449%val1 = add i32 4, 4
5450%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5451 <i>; yields {i32}:result1 = 4</i>
5452%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5453%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5454
5455%val2 = add i32 1, 1
5456%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5457 <i>; yields {i32}:result2 = 8</i>
5458%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5459
5460%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5461</pre>
5462</div>
5463
5464<!-- _______________________________________________________________________ -->
5465<div class="doc_subsubsection">
5466 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5467</div>
5468<div class="doc_text">
5469<h5>Syntax:</h5>
5470
5471<p>
5472 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5473 integer bit width. Not all targets support all bit widths however.</p>
5474<pre>
5475declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5476declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5477declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5478declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5479
5480</pre>
5481<h5>Overview:</h5>
5482<p>
5483 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5484 the value from memory. It then stores the value in <tt>val</tt> in the memory
5485 at <tt>ptr</tt>.
5486</p>
5487<h5>Arguments:</h5>
5488
5489<p>
5490 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5491 <tt>val</tt> argument and the result must be integers of the same bit width.
5492 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5493 integer type. The targets may only lower integer representations they
5494 support.
5495</p>
5496<h5>Semantics:</h5>
5497<p>
5498 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5499 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5500 equivalent of an atomic swap operation within the SSA framework.
5501
5502</p>
5503<h5>Examples:</h5>
5504<pre>
5505%ptr = malloc i32
5506 store i32 4, %ptr
5507
5508%val1 = add i32 4, 4
5509%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5510 <i>; yields {i32}:result1 = 4</i>
5511%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5512%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5513
5514%val2 = add i32 1, 1
5515%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5516 <i>; yields {i32}:result2 = 8</i>
5517
5518%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5519%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5520</pre>
5521</div>
5522
5523<!-- _______________________________________________________________________ -->
5524<div class="doc_subsubsection">
5525 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5526
5527</div>
5528<div class="doc_text">
5529<h5>Syntax:</h5>
5530<p>
5531 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5532 integer bit width. Not all targets support all bit widths however.</p>
5533<pre>
5534declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5535declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5536declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5537declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5538
5539</pre>
5540<h5>Overview:</h5>
5541<p>
5542 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5543 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5544</p>
5545<h5>Arguments:</h5>
5546<p>
5547
5548 The intrinsic takes two arguments, the first a pointer to an integer value
5549 and the second an integer value. The result is also an integer value. These
5550 integer types can have any bit width, but they must all have the same bit
5551 width. The targets may only lower integer representations they support.
5552</p>
5553<h5>Semantics:</h5>
5554<p>
5555 This intrinsic does a series of operations atomically. It first loads the
5556 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5557 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5558</p>
5559
5560<h5>Examples:</h5>
5561<pre>
5562%ptr = malloc i32
5563 store i32 4, %ptr
5564%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5565 <i>; yields {i32}:result1 = 4</i>
5566%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5567 <i>; yields {i32}:result2 = 8</i>
5568%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5569 <i>; yields {i32}:result3 = 10</i>
5570%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5571</pre>
5572</div>
5573
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5574
5575<!-- ======================================================================= -->
5576<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5577 <a name="int_general">General Intrinsics</a>
5578</div>
5579
5580<div class="doc_text">
5581<p> This class of intrinsics is designed to be generic and has
5582no specific purpose. </p>
5583</div>
5584
5585<!-- _______________________________________________________________________ -->
5586<div class="doc_subsubsection">
5587 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5588</div>
5589
5590<div class="doc_text">
5591
5592<h5>Syntax:</h5>
5593<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5594 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]5595</pre>
5596
5597<h5>Overview:</h5>
5598
5599<p>
5600The '<tt>llvm.var.annotation</tt>' intrinsic
5601</p>
5602
5603<h5>Arguments:</h5>
5604
5605<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5606The first argument is a pointer to a value, the second is a pointer to a
5607global string, the third is a pointer to a global string which is the source
5608file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5609</p>
5610
5611<h5>Semantics:</h5>
5612
5613<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5614This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5615This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5616annotations. These have no other defined use, they are ignored by code
5617generation and optimization.
5618</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5619</div>
5620
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5621<!-- _______________________________________________________________________ -->
5622<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5623 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5624</div>
5625
5626<div class="doc_text">
5627
5628<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5629<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5630any integer bit width.
5631</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5632<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]5633 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5634 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5635 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5636 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5637 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]5638</pre>
5639
5640<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5641
5642<p>
5643The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5644</p>
5645
5646<h5>Arguments:</h5>
5647
5648<p>
5649The first argument is an integer value (result of some expression),
5650the second is a pointer to a global string, the third is a pointer to a global
5651string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5652It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5653</p>
5654
5655<h5>Semantics:</h5>
5656
5657<p>
5658This intrinsic allows annotations to be put on arbitrary expressions
5659with arbitrary strings. This can be useful for special purpose optimizations
5660that want to look for these annotations. These have no other defined use, they
5661are ignored by code generation and optimization.
5662</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5663
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5664<!-- _______________________________________________________________________ -->
5665<div class="doc_subsubsection">
5666 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5667</div>
5668
5669<div class="doc_text">
5670
5671<h5>Syntax:</h5>
5672<pre>
5673 declare void @llvm.trap()
5674</pre>
5675
5676<h5>Overview:</h5>
5677
5678<p>
5679The '<tt>llvm.trap</tt>' intrinsic
5680</p>
5681
5682<h5>Arguments:</h5>
5683
5684<p>
5685None
5686</p>
5687
5688<h5>Semantics:</h5>
5689
5690<p>
5691This intrinsics is lowered to the target dependent trap instruction. If the
5692target does not have a trap instruction, this intrinsic will be lowered to the
5693call of the abort() function.
5694</p>
5695</div>
5696
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5697<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5698<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5699<address>
5700 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5701 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5702 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]5703 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5704
5705 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]5706 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5707 Last modified: $Date$
5708</address>
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