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gerrit-public.fairphone.software / toolchain / llvm-project / c50977b02538aa0c3bfd1f5f4651f97cec3c45e1 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
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 Korobeynikov25b2e822008-03-22 08:36:14 +0000[diff] [blame]766 function, global variable, another alias or bitcast of global value). Aliases
767 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]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
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1228consists of a return type and a list of formal parameter types. The
1229return type of a function type is a scalar type or a struct type. If the
1230return type is a struct type then all struct elements must be of a first
1231class type. Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1232(which are structures of pointers to functions), for indirect function
1233calls, and when defining a function.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1234
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1235<h5>Syntax:</h5>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1236<pre> &lt;returntype list&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1237<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]1238specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1239which indicates that the function takes a variable number of arguments.
1240Variable argument functions can access their arguments with the <a
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1241 href="#int_varargs">variable argument handling intrinsic</a> functions.
1242'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1243<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1244<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1245<table class="layout">
1246 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1247 <td class="left"><tt>i32 (i32)</tt></td>
1248 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1249 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1250 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1251 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1252 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1253 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1254 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1255 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1256 <tt>float</tt>.
1257 </td>
1258 </tr><tr class="layout">
1259 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1260 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1261 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1262 which returns an integer. This is the signature for <tt>printf</tt> in
1263 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1264 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]1265 </tr><tr class="layout">
1266 <td class="left"><tt>{i32, i32} (i32)</tt></td>
1267 <td class="left">A function taking an <tt>i32></tt>, returning two values
1268 <tt> i32 </tt> as an arggregate of type <tt>{ i32, i32 }</tt>
1269 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1270 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1271</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1272
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1273</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1274<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1275<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1276<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1277<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1278<p>The structure type is used to represent a collection of data members
1279together in memory. The packing of the field types is defined to match
1280the ABI of the underlying processor. The elements of a structure may
1281be any type that has a size.</p>
1282<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1283and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1284field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1285instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1286<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1287<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1288<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1289<table class="layout">
1290 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1291 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1292 <td class="left">A triple of three <tt>i32</tt> values</td>
1293 </tr><tr class="layout">
1294 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1295 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1296 second element is a <a href="#t_pointer">pointer</a> to a
1297 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1298 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1299 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1300</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1301</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1302
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1303<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1304<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1305</div>
1306<div class="doc_text">
1307<h5>Overview:</h5>
1308<p>The packed structure type is used to represent a collection of data members
1309together in memory. There is no padding between fields. Further, the alignment
1310of a packed structure is 1 byte. The elements of a packed structure may
1311be any type that has a size.</p>
1312<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1313and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1314field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1315instruction.</p>
1316<h5>Syntax:</h5>
1317<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1318<h5>Examples:</h5>
1319<table class="layout">
1320 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1321 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1322 <td class="left">A triple of three <tt>i32</tt> values</td>
1323 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1324 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1325 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1326 second element is a <a href="#t_pointer">pointer</a> to a
1327 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1328 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1329 </tr>
1330</table>
1331</div>
1332
1333<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1334<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1335<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1336<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1337<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1338reference to another object, which must live in memory. Pointer types may have
1339an optional address space attribute defining the target-specific numbered
1340address space where the pointed-to object resides. The default address space is
1341zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1342<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1343<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1344<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1345<table class="layout">
1346 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1347 <td class="left"><tt>[4x i32]*</tt></td>
1348 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1349 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1350 </tr>
1351 <tr class="layout">
1352 <td class="left"><tt>i32 (i32 *) *</tt></td>
1353 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1354 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1355 <tt>i32</tt>.</td>
1356 </tr>
1357 <tr class="layout">
1358 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1359 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1360 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1361 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1362</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1363</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1364
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1365<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1366<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1367<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1368
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1369<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1370
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1371<p>A vector type is a simple derived type that represents a vector
1372of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1373are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1374A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1375elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1376of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1377considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1378
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1379<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1380
1381<pre>
1382 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1383</pre>
1384
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1385<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1386be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1387
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1388<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1389
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1390<table class="layout">
1391 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1392 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1393 <td class="left">Vector of 4 32-bit integer values.</td>
1394 </tr>
1395 <tr class="layout">
1396 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1397 <td class="left">Vector of 8 32-bit floating-point values.</td>
1398 </tr>
1399 <tr class="layout">
1400 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1401 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1402 </tr>
1403</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1404</div>
1405
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1406<!-- _______________________________________________________________________ -->
1407<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411
1412<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1413corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1414In LLVM, opaque types can eventually be resolved to any type (not just a
1415structure type).</p>
1416
1417<h5>Syntax:</h5>
1418
1419<pre>
1420 opaque
1421</pre>
1422
1423<h5>Examples:</h5>
1424
1425<table class="layout">
1426 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1427 <td class="left"><tt>opaque</tt></td>
1428 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1429 </tr>
1430</table>
1431</div>
1432
1433
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1434<!-- *********************************************************************** -->
1435<div class="doc_section"> <a name="constants">Constants</a> </div>
1436<!-- *********************************************************************** -->
1437
1438<div class="doc_text">
1439
1440<p>LLVM has several different basic types of constants. This section describes
1441them all and their syntax.</p>
1442
1443</div>
1444
1445<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1446<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1447
1448<div class="doc_text">
1449
1450<dl>
1451 <dt><b>Boolean constants</b></dt>
1452
1453 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1454 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1455 </dd>
1456
1457 <dt><b>Integer constants</b></dt>
1458
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1459 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1460 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1461 integer types.
1462 </dd>
1463
1464 <dt><b>Floating point constants</b></dt>
1465
1466 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1467 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1468 notation (see below). Floating point constants must have a <a
1469 href="#t_floating">floating point</a> type. </dd>
1470
1471 <dt><b>Null pointer constants</b></dt>
1472
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1473 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1474 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1475
1476</dl>
1477
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1478<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1479of floating point constants. For example, the form '<tt>double
14800x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14814.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1482(and the only time that they are generated by the disassembler) is when a
1483floating point constant must be emitted but it cannot be represented as a
1484decimal floating point number. For example, NaN's, infinities, and other
1485special values are represented in their IEEE hexadecimal format so that
1486assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1487
1488</div>
1489
1490<!-- ======================================================================= -->
1491<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1492</div>
1493
1494<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1495<p>Aggregate constants arise from aggregation of simple constants
1496and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1497
1498<dl>
1499 <dt><b>Structure constants</b></dt>
1500
1501 <dd>Structure constants are represented with notation similar to structure
1502 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1503 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1504 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]1505 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1506 types of elements must match those specified by the type.
1507 </dd>
1508
1509 <dt><b>Array constants</b></dt>
1510
1511 <dd>Array constants are represented with notation similar to array type
1512 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1513 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1514 constants must have <a href="#t_array">array type</a>, and the number and
1515 types of elements must match those specified by the type.
1516 </dd>
1517
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1518 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1519
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1520 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1521 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1522 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]1523 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1524 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1525 match those specified by the type.
1526 </dd>
1527
1528 <dt><b>Zero initialization</b></dt>
1529
1530 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1531 value to zero of <em>any</em> type, including scalar and aggregate types.
1532 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]1533 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1534 initializers.
1535 </dd>
1536</dl>
1537
1538</div>
1539
1540<!-- ======================================================================= -->
1541<div class="doc_subsection">
1542 <a name="globalconstants">Global Variable and Function Addresses</a>
1543</div>
1544
1545<div class="doc_text">
1546
1547<p>The addresses of <a href="#globalvars">global variables</a> and <a
1548href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1549constants. These constants are explicitly referenced when the <a
1550href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1551href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1552file:</p>
1553
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1554<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1555<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1556@X = global i32 17
1557@Y = global i32 42
1558@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1559</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1560</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1561
1562</div>
1563
1564<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1565<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1566<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1567 <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]1568 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1569 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1570
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1571 <p>Undefined values indicate to the compiler that the program is well defined
1572 no matter what value is used, giving the compiler more freedom to optimize.
1573 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1574</div>
1575
1576<!-- ======================================================================= -->
1577<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1578</div>
1579
1580<div class="doc_text">
1581
1582<p>Constant expressions are used to allow expressions involving other constants
1583to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1584href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1585that does not have side effects (e.g. load and call are not supported). The
1586following is the syntax for constant expressions:</p>
1587
1588<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1589 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1590 <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]1591 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1592
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1593 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1594 <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]1595 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]1596
1597 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1598 <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]1599 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]1600
1601 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1602 <dd>Truncate a floating point constant to another floating point type. The
1603 size of CST must be larger than the size of TYPE. Both types must be
1604 floating point.</dd>
1605
1606 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1607 <dd>Floating point extend a constant to another type. The size of CST must be
1608 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1609
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1610 <dt><b><tt>fptoui ( 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 unsigned 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>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1618 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1619 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1620 or vector floating point 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 integer type,
1622 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>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1625 <dd>Convert an unsigned 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 Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1631 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1632 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1633 constant. TYPE must be a scalar or vector floating point type. CST must be of
1634 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1635 of the same number of elements. If the value won't fit in the floating point
1636 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1637
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1638 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1639 <dd>Convert a pointer typed constant to the corresponding integer constant
1640 TYPE must be an integer type. CST must be of pointer type. The CST value is
1641 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1642
1643 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1644 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1645 pointer type. CST must be of integer type. The CST value is zero extended,
1646 truncated, or unchanged to make it fit in a pointer size. This one is
1647 <i>really</i> dangerous!</dd>
1648
1649 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1650 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1651 identical (same number of bits). The conversion is done as if the CST value
1652 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]1653 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1654 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]1655 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1656 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1657
1658 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1659
1660 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1661 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1662 instruction, the index list may have zero or more indexes, which are required
1663 to make sense for the type of "CSTPTR".</dd>
1664
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1665 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1666
1667 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1668 constants.</dd>
1669
1670 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1671 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1672
1673 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1674 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1675
1676 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1677
1678 <dd>Perform the <a href="#i_extractelement">extractelement
1679 operation</a> on constants.
1680
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1681 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1682
1683 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1684 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1685
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1686
1687 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1688
1689 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1690 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1691
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1692 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1693
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1694 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1695 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1696 binary</a> operations. The constraints on operands are the same as those for
1697 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1698 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1699</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1700</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1701
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1702<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1703<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1704<!-- *********************************************************************** -->
1705
1706<!-- ======================================================================= -->
1707<div class="doc_subsection">
1708<a name="inlineasm">Inline Assembler Expressions</a>
1709</div>
1710
1711<div class="doc_text">
1712
1713<p>
1714LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1715Module-Level Inline Assembly</a>) through the use of a special value. This
1716value represents the inline assembler as a string (containing the instructions
1717to emit), a list of operand constraints (stored as a string), and a flag that
1718indicates whether or not the inline asm expression has side effects. An example
1719inline assembler expression is:
1720</p>
1721
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1722<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1723<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1724i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1725</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1726</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1727
1728<p>
1729Inline assembler expressions may <b>only</b> be used as the callee operand of
1730a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1731</p>
1732
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1733<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1734<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1735%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]1736</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1737</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1738
1739<p>
1740Inline asms with side effects not visible in the constraint list must be marked
1741as having side effects. This is done through the use of the
1742'<tt>sideeffect</tt>' keyword, like so:
1743</p>
1744
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1745<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1746<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1747call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1748</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1749</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1750
1751<p>TODO: The format of the asm and constraints string still need to be
1752documented here. Constraints on what can be done (e.g. duplication, moving, etc
1753need to be documented).
1754</p>
1755
1756</div>
1757
1758<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1759<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1760<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1762<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1763
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1764<p>The LLVM instruction set consists of several different
1765classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1766instructions</a>, <a href="#binaryops">binary instructions</a>,
1767<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1768 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1769instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1770
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1771</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1772
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1773<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1774<div class="doc_subsection"> <a name="terminators">Terminator
1775Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1776
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1777<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1778
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1779<p>As mentioned <a href="#functionstructure">previously</a>, every
1780basic block in a program ends with a "Terminator" instruction, which
1781indicates which block should be executed after the current block is
1782finished. These terminator instructions typically yield a '<tt>void</tt>'
1783value: they produce control flow, not values (the one exception being
1784the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1785<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1786 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1787instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1788the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1789 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1790 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1791
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1792</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1793
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1794<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1795<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1796Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1797<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1798<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1799<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]1800 ret void <i>; Return from void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1801 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]1802</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1803<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1804<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1805value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1806<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1807returns a value and then causes control flow, and one that just causes
1808control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1809<h5>Arguments:</h5>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1810<p>The '<tt>ret</tt>' instruction may return one or multiple values. The
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1811type of each return value must be a '<a href="#t_firstclass">first class</a>'
1812 type. Note that a function is not <a href="#wellformed">well formed</a>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1813if there exists a '<tt>ret</tt>' instruction inside of the function that
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1814returns values that do not match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1815<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1816<p>When the '<tt>ret</tt>' instruction is executed, control flow
1817returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1818 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1819the instruction after the call. If the caller was an "<a
1820 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1821at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1822returns a value, that value shall set the call or invoke instruction's
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1823return value. If the instruction returns multiple values then these
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1824values can only be accessed through a '<a href="#i_getresult"><tt>getresult</tt>
1825</a>' instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1826<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1827<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1828 ret void <i>; Return from a void function</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1829 ret i32 4, i8 2 <i>; Return two values 4 and 2 </i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1830</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1831</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1832<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1833<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1834<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1835<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1836<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]1837</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1838<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1839<p>The '<tt>br</tt>' instruction is used to cause control flow to
1840transfer to a different basic block in the current function. There are
1841two forms of this instruction, corresponding to a conditional branch
1842and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1843<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1844<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1845single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1846unconditional form of the '<tt>br</tt>' instruction takes a single
1847'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1848<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1849<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1850argument is evaluated. If the value is <tt>true</tt>, control flows
1851to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1852control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1853<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1854<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]1855 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]1856</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1857<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1858<div class="doc_subsubsection">
1859 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1860</div>
1861
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1862<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1863<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1864
1865<pre>
1866 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1867</pre>
1868
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1869<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1870
1871<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1872several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1873instruction, allowing a branch to occur to one of many possible
1874destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1875
1876
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1877<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1878
1879<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1880comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1881an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1882table is not allowed to contain duplicate constant entries.</p>
1883
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1884<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1885
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1886<p>The <tt>switch</tt> instruction specifies a table of values and
1887destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1888table is searched for the given value. If the value is found, control flow is
1889transfered to the corresponding destination; otherwise, control flow is
1890transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1891
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1892<h5>Implementation:</h5>
1893
1894<p>Depending on properties of the target machine and the particular
1895<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1896ways. For example, it could be generated as a series of chained conditional
1897branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1898
1899<h5>Example:</h5>
1900
1901<pre>
1902 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1903 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1904 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1905
1906 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1907 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1908
1909 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1910 switch i32 %val, label %otherwise [ i32 0, label %onzero
1911 i32 1, label %onone
1912 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1913</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1914</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1916<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1917<div class="doc_subsubsection">
1918 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1919</div>
1920
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1921<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1922
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1923<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1924
1925<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1926 &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]1927 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1928</pre>
1929
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1930<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1931
1932<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1933function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1934'<tt>normal</tt>' label or the
1935'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1936"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1937"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1938href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1939continued at the dynamically nearest "exception" label. If the callee function
Devang Pateld0f47642008-03-11 05:51:59 +0000[diff] [blame]1940returns multiple values then individual return values are only accessible through
1941a '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1942
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1943<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1944
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1945<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1946
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1947<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1948 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1949 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1950 convention</a> the call should use. If none is specified, the call defaults
1951 to using C calling conventions.
1952 </li>
1953 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1954 function value being invoked. In most cases, this is a direct function
1955 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1956 an arbitrary pointer to function value.
1957 </li>
1958
1959 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1960 function to be invoked. </li>
1961
1962 <li>'<tt>function args</tt>': argument list whose types match the function
1963 signature argument types. If the function signature indicates the function
1964 accepts a variable number of arguments, the extra arguments can be
1965 specified. </li>
1966
1967 <li>'<tt>normal label</tt>': the label reached when the called function
1968 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1969
1970 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1971 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1972
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1973</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1974
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1976
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1977<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1978href="#i_call">call</a></tt>' instruction in most regards. The primary
1979difference is that it establishes an association with a label, which is used by
1980the runtime library to unwind the stack.</p>
1981
1982<p>This instruction is used in languages with destructors to ensure that proper
1983cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1984exception. Additionally, this is important for implementation of
1985'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1986
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1987<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1988<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1989 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1990 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]1991 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1992 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1993</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1994</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1995
1996
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1997<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1998
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1999<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2000Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2001
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2002<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2003
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2004<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2005<pre>
2006 unwind
2007</pre>
2008
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2009<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2010
2011<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2012at the first callee in the dynamic call stack which used an <a
2013href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2014primarily used to implement exception handling.</p>
2015
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]2016<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2017
2018<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
2019immediately halt. The dynamic call stack is then searched for the first <a
2020href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2021execution continues at the "exceptional" destination block specified by the
2022<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2023dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2024</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2025
2026<!-- _______________________________________________________________________ -->
2027
2028<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2029Instruction</a> </div>
2030
2031<div class="doc_text">
2032
2033<h5>Syntax:</h5>
2034<pre>
2035 unreachable
2036</pre>
2037
2038<h5>Overview:</h5>
2039
2040<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2041instruction is used to inform the optimizer that a particular portion of the
2042code is not reachable. This can be used to indicate that the code after a
2043no-return function cannot be reached, and other facts.</p>
2044
2045<h5>Semantics:</h5>
2046
2047<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2048</div>
2049
2050
2051
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2052<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2053<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2054<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2055<p>Binary operators are used to do most of the computation in a
2056program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2057produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2058multiple 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]2059The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2060necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2061<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2062</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2063<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2064<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2065Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2066<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2067<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2068<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]2069</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2070<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2071<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2072<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2073<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2074 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2075 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]2076Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2077<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2078<p>The value produced is the integer or floating point sum of the two
2079operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2080<p>If an integer sum has unsigned overflow, the result returned is the
2081mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2082the result.</p>
2083<p>Because LLVM integers use a two's complement representation, this
2084instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2085<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2086<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]2087</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2088</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2089<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2090<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2091Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2092<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2093<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2094<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]2095</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2096<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2097<p>The '<tt>sub</tt>' instruction returns the difference of its two
2098operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2099<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2100instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2102<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2103 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2104values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2105This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2106Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2107<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2108<p>The value produced is the integer or floating point difference of
2109the two operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2110<p>If an integer difference has unsigned overflow, the result returned is the
2111mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2112the result.</p>
2113<p>Because LLVM integers use a two's complement representation, this
2114instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2115<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2116<pre>
2117 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2118 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2119</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2120</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2121<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2122<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2123Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2124<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2125<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2126<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]2127</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2128<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2129<p>The '<tt>mul</tt>' instruction returns the product of its two
2130operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2131<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2132<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2133 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2134values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2135This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2136Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2137<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2138<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2139two operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2140<p>If the result of an integer multiplication has unsigned overflow,
2141the result returned is the mathematical result modulo
21422<sup>n</sup>, where n is the bit width of the result.</p>
2143<p>Because LLVM integers use a two's complement representation, and the
2144result is the same width as the operands, this instruction returns the
2145correct result for both signed and unsigned integers. If a full product
2146(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2147should be sign-extended or zero-extended as appropriate to the
2148width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2149<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2150<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]2151</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2152</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2153<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2154<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2155</a></div>
2156<div class="doc_text">
2157<h5>Syntax:</h5>
2158<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2159</pre>
2160<h5>Overview:</h5>
2161<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2162operands.</p>
2163<h5>Arguments:</h5>
2164<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2165<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2166types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2167of the values in which case the elements must be integers.</p>
2168<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2169<p>The value produced is the unsigned integer quotient of the two operands.</p>
2170<p>Note that unsigned integer division and signed integer division are distinct
2171operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2172<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2173<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2174<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]2175</pre>
2176</div>
2177<!-- _______________________________________________________________________ -->
2178<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2179</a> </div>
2180<div class="doc_text">
2181<h5>Syntax:</h5>
2182<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2183</pre>
2184<h5>Overview:</h5>
2185<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2186operands.</p>
2187<h5>Arguments:</h5>
2188<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2189<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2190types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2191of the values in which case the elements must be integers.</p>
2192<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2193<p>The value produced is the signed integer quotient of the two operands.</p>
2194<p>Note that signed integer division and unsigned integer division are distinct
2195operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2196<p>Division by zero leads to undefined behavior. Overflow also leads to
2197undefined behavior; this is a rare case, but can occur, for example,
2198by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2199<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2200<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]2201</pre>
2202</div>
2203<!-- _______________________________________________________________________ -->
2204<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2205Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2206<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2207<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2208<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]2209</pre>
2210<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2211<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2212operands.</p>
2213<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2214<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2215<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2216identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2217versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2218<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2219<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2220<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2221<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]2222</pre>
2223</div>
2224<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2225<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2226</div>
2227<div class="doc_text">
2228<h5>Syntax:</h5>
2229<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2230</pre>
2231<h5>Overview:</h5>
2232<p>The '<tt>urem</tt>' instruction returns the remainder from the
2233unsigned division of its two arguments.</p>
2234<h5>Arguments:</h5>
2235<p>The two arguments to the '<tt>urem</tt>' instruction must be
2236<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2237types. This instruction can also take <a href="#t_vector">vector</a> versions
2238of the values in which case the elements must be integers.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2239<h5>Semantics:</h5>
2240<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2241This instruction always performs an unsigned division to get the remainder,
2242regardless of whether the arguments are unsigned or not.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2243<p>Note that unsigned integer remainder and signed integer remainder are
2244distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2245<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2246<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2247<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]2248</pre>
2249
2250</div>
2251<!-- _______________________________________________________________________ -->
2252<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2253Instruction</a> </div>
2254<div class="doc_text">
2255<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2256<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]2257</pre>
2258<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2259<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2260signed division of its two operands. This instruction can also take
2261<a href="#t_vector">vector</a> versions of the values in which case
2262the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2263
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2264<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2265<p>The two arguments to the '<tt>srem</tt>' instruction must be
2266<a href="#t_integer">integer</a> values. Both arguments must have identical
2267types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2268<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2269<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2270has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2271operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2272a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2273 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2274Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2275please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2276Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2277<p>Note that signed integer remainder and unsigned integer remainder are
2278distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2279<p>Taking the remainder of a division by zero leads to undefined behavior.
2280Overflow also leads to undefined behavior; this is a rare case, but can occur,
2281for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2282(The remainder doesn't actually overflow, but this rule lets srem be
2283implemented using instructions that return both the result of the division
2284and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2285<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2286<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]2287</pre>
2288
2289</div>
2290<!-- _______________________________________________________________________ -->
2291<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2292Instruction</a> </div>
2293<div class="doc_text">
2294<h5>Syntax:</h5>
2295<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2296</pre>
2297<h5>Overview:</h5>
2298<p>The '<tt>frem</tt>' instruction returns the remainder from the
2299division of its two operands.</p>
2300<h5>Arguments:</h5>
2301<p>The two arguments to the '<tt>frem</tt>' instruction must be
2302<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2303identical types. This instruction can also take <a href="#t_vector">vector</a>
2304versions of floating point values.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2305<h5>Semantics:</h5>
2306<p>This instruction returns the <i>remainder</i> of a division.</p>
2307<h5>Example:</h5>
2308<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]2309</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2310</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2311
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2312<!-- ======================================================================= -->
2313<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2314Operations</a> </div>
2315<div class="doc_text">
2316<p>Bitwise binary operators are used to do various forms of
2317bit-twiddling in a program. They are generally very efficient
2318instructions and can commonly be strength reduced from other
2319instructions. They require two operands, execute an operation on them,
2320and produce a single value. The resulting value of the bitwise binary
2321operators is always the same type as its first operand.</p>
2322</div>
2323
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2324<!-- _______________________________________________________________________ -->
2325<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2326Instruction</a> </div>
2327<div class="doc_text">
2328<h5>Syntax:</h5>
2329<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2330</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2331
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2332<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2333
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2334<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2335the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2336
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2337<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2338
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2339<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2340 href="#t_integer">integer</a> type.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2341
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2342<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2343
2344<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2345<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2346of bits in <tt>var1</tt>, the result is undefined.</p>
2347
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2348<h5>Example:</h5><pre>
2349 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2350 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2351 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2352 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2353</pre>
2354</div>
2355<!-- _______________________________________________________________________ -->
2356<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2357Instruction</a> </div>
2358<div class="doc_text">
2359<h5>Syntax:</h5>
2360<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2361</pre>
2362
2363<h5>Overview:</h5>
2364<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2365operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2366
2367<h5>Arguments:</h5>
2368<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2369<a href="#t_integer">integer</a> type.</p>
2370
2371<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2372
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2373<p>This instruction always performs a logical shift right operation. The most
2374significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2375shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2376the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2377
2378<h5>Example:</h5>
2379<pre>
2380 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2381 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2382 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2383 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2384 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2385</pre>
2386</div>
2387
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2388<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2389<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2390Instruction</a> </div>
2391<div class="doc_text">
2392
2393<h5>Syntax:</h5>
2394<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2395</pre>
2396
2397<h5>Overview:</h5>
2398<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2399operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2400
2401<h5>Arguments:</h5>
2402<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2403<a href="#t_integer">integer</a> type.</p>
2404
2405<h5>Semantics:</h5>
2406<p>This instruction always performs an arithmetic shift right operation,
2407The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2408of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2409larger than the number of bits in <tt>var1</tt>, the result is undefined.
2410</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2411
2412<h5>Example:</h5>
2413<pre>
2414 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2415 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2416 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2417 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2418 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2419</pre>
2420</div>
2421
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2422<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2423<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2424Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2425<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2426<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2427<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]2428</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2429<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2430<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2431its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2432<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2433<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2434 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2435identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2436<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2437<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2438<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2439<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2440<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2441 <tbody>
2442 <tr>
2443 <td>In0</td>
2444 <td>In1</td>
2445 <td>Out</td>
2446 </tr>
2447 <tr>
2448 <td>0</td>
2449 <td>0</td>
2450 <td>0</td>
2451 </tr>
2452 <tr>
2453 <td>0</td>
2454 <td>1</td>
2455 <td>0</td>
2456 </tr>
2457 <tr>
2458 <td>1</td>
2459 <td>0</td>
2460 <td>0</td>
2461 </tr>
2462 <tr>
2463 <td>1</td>
2464 <td>1</td>
2465 <td>1</td>
2466 </tr>
2467 </tbody>
2468</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2469</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2470<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2471<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2472 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2473 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2474</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2475</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2476<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2477<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2478<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2479<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2480<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]2481</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2482<h5>Overview:</h5>
2483<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2484or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2485<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2486<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2487 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2488identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2489<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2490<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2491<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2492<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2493<table border="1" cellspacing="0" cellpadding="4">
2494 <tbody>
2495 <tr>
2496 <td>In0</td>
2497 <td>In1</td>
2498 <td>Out</td>
2499 </tr>
2500 <tr>
2501 <td>0</td>
2502 <td>0</td>
2503 <td>0</td>
2504 </tr>
2505 <tr>
2506 <td>0</td>
2507 <td>1</td>
2508 <td>1</td>
2509 </tr>
2510 <tr>
2511 <td>1</td>
2512 <td>0</td>
2513 <td>1</td>
2514 </tr>
2515 <tr>
2516 <td>1</td>
2517 <td>1</td>
2518 <td>1</td>
2519 </tr>
2520 </tbody>
2521</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2522</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2523<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2524<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2525 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2526 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2527</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2528</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2529<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2530<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2531Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2532<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2533<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2534<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]2535</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2536<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2537<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2538or of its two operands. The <tt>xor</tt> is used to implement the
2539"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2540<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2541<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2542 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2543identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2544<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2545<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2546<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2547<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2548<table border="1" cellspacing="0" cellpadding="4">
2549 <tbody>
2550 <tr>
2551 <td>In0</td>
2552 <td>In1</td>
2553 <td>Out</td>
2554 </tr>
2555 <tr>
2556 <td>0</td>
2557 <td>0</td>
2558 <td>0</td>
2559 </tr>
2560 <tr>
2561 <td>0</td>
2562 <td>1</td>
2563 <td>1</td>
2564 </tr>
2565 <tr>
2566 <td>1</td>
2567 <td>0</td>
2568 <td>1</td>
2569 </tr>
2570 <tr>
2571 <td>1</td>
2572 <td>1</td>
2573 <td>0</td>
2574 </tr>
2575 </tbody>
2576</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2577</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2578<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2579<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2580<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2581 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2582 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2583 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2584</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2585</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2586
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2587<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2588<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2589 <a name="vectorops">Vector Operations</a>
2590</div>
2591
2592<div class="doc_text">
2593
2594<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2595target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2596vector-specific operations needed to process vectors effectively. While LLVM
2597does directly support these vector operations, many sophisticated algorithms
2598will want to use target-specific intrinsics to take full advantage of a specific
2599target.</p>
2600
2601</div>
2602
2603<!-- _______________________________________________________________________ -->
2604<div class="doc_subsubsection">
2605 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2606</div>
2607
2608<div class="doc_text">
2609
2610<h5>Syntax:</h5>
2611
2612<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2613 &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]2614</pre>
2615
2616<h5>Overview:</h5>
2617
2618<p>
2619The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2620element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2621</p>
2622
2623
2624<h5>Arguments:</h5>
2625
2626<p>
2627The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2628value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2629an index indicating the position from which to extract the element.
2630The index may be a variable.</p>
2631
2632<h5>Semantics:</h5>
2633
2634<p>
2635The result is a scalar of the same type as the element type of
2636<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2637<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2638results are undefined.
2639</p>
2640
2641<h5>Example:</h5>
2642
2643<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2644 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2645</pre>
2646</div>
2647
2648
2649<!-- _______________________________________________________________________ -->
2650<div class="doc_subsubsection">
2651 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2652</div>
2653
2654<div class="doc_text">
2655
2656<h5>Syntax:</h5>
2657
2658<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2659 &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]2660</pre>
2661
2662<h5>Overview:</h5>
2663
2664<p>
2665The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2666element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2667</p>
2668
2669
2670<h5>Arguments:</h5>
2671
2672<p>
2673The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2674value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2675scalar value whose type must equal the element type of the first
2676operand. The third operand is an index indicating the position at
2677which to insert the value. The index may be a variable.</p>
2678
2679<h5>Semantics:</h5>
2680
2681<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2682The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2683element values are those of <tt>val</tt> except at position
2684<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2685exceeds the length of <tt>val</tt>, the results are undefined.
2686</p>
2687
2688<h5>Example:</h5>
2689
2690<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2691 %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]2692</pre>
2693</div>
2694
2695<!-- _______________________________________________________________________ -->
2696<div class="doc_subsubsection">
2697 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2698</div>
2699
2700<div class="doc_text">
2701
2702<h5>Syntax:</h5>
2703
2704<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2705 &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]2706</pre>
2707
2708<h5>Overview:</h5>
2709
2710<p>
2711The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2712from two input vectors, returning a vector of the same type.
2713</p>
2714
2715<h5>Arguments:</h5>
2716
2717<p>
2718The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2719with types that match each other and types that match the result of the
2720instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2721of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2722</p>
2723
2724<p>
2725The shuffle mask operand is required to be a constant vector with either
2726constant integer or undef values.
2727</p>
2728
2729<h5>Semantics:</h5>
2730
2731<p>
2732The elements of the two input vectors are numbered from left to right across
2733both of the vectors. The shuffle mask operand specifies, for each element of
2734the result vector, which element of the two input registers the result element
2735gets. The element selector may be undef (meaning "don't care") and the second
2736operand may be undef if performing a shuffle from only one vector.
2737</p>
2738
2739<h5>Example:</h5>
2740
2741<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2742 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2743 &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]2744 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2745 &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]2746</pre>
2747</div>
2748
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2749
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2750<!-- ======================================================================= -->
2751<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2752 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2753</div>
2754
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2755<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2756
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2757<p>A key design point of an SSA-based representation is how it
2758represents memory. In LLVM, no memory locations are in SSA form, which
2759makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2760allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2761
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2762</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2764<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2765<div class="doc_subsubsection">
2766 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2767</div>
2768
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2769<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2770
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2771<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2772
2773<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2774 &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]2775</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2776
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2777<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2778
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2779<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2780heap and returns a pointer to it. The object is always allocated in the generic
2781address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2782
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2783<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2784
2785<p>The '<tt>malloc</tt>' instruction allocates
2786<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2787bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2788appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]2789number of elements allocated, otherwise "NumElements" is defaulted to be one.
2790If an alignment is specified, the value result of the allocation is guaranteed to
2791be aligned to at least that boundary. If not specified, or if zero, the target can
2792choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2793
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2794<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2795
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2796<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2797
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2798<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2799a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2800
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2801<h5>Example:</h5>
2802
2803<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2804 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2805
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2806 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2807 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2808 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2809 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2810 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2811</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2812</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2813
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2814<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2815<div class="doc_subsubsection">
2816 <a name="i_free">'<tt>free</tt>' Instruction</a>
2817</div>
2818
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2819<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2820
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2821<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2822
2823<pre>
2824 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2825</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2826
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2827<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2828
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2829<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2830memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2831
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2832<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2833
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2834<p>'<tt>value</tt>' shall be a pointer value that points to a value
2835that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2836instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2837
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2838<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2839
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2840<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2841after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2842
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2843<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2844
2845<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2846 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2847 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2848</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2849</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2850
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2851<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2852<div class="doc_subsubsection">
2853 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2854</div>
2855
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2856<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2857
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2858<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2859
2860<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2861 &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]2862</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2863
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2864<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2865
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2866<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2867currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2868returns to its caller. The object is always allocated in the generic address
2869space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2870
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2871<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2872
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2873<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2874bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]2875appropriate type to the program. If "NumElements" is specified, it is the
2876number of elements allocated, otherwise "NumElements" is defaulted to be one.
2877If an alignment is specified, the value result of the allocation is guaranteed
2878to be aligned to at least that boundary. If not specified, or if zero, the target
2879can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2880
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2881<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2882
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2883<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2884
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2885<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2886memory is automatically released when the function returns. The '<tt>alloca</tt>'
2887instruction is commonly used to represent automatic variables that must
2888have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2889 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]2890instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2891
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2892<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2893
2894<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2895 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2896 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2897 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2898 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2899</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2900</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2901
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2902<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2903<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2904Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2905<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2906<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2907<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]2908<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2909<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2910<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2911<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2912address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2913 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2914marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2915the number or order of execution of this <tt>load</tt> with other
2916volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2917instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2918<p>
2919The optional "align" argument specifies the alignment of the operation
2920(that is, the alignment of the memory address). A value of 0 or an
2921omitted "align" argument means that the operation has the preferential
2922alignment for the target. It is the responsibility of the code emitter
2923to ensure that the alignment information is correct. Overestimating
2924the alignment results in an undefined behavior. Underestimating the
2925alignment may produce less efficient code. An alignment of 1 is always
2926safe.
2927</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2928<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2929<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2930<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2931<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2932 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2933 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2934 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2935</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2936</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2937<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2938<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2939Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2940<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2941<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2942<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2943 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]2944</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2945<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2946<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2947<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2948<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2949to 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]2950operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2951operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2952optimizer is not allowed to modify the number or order of execution of
2953this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2954 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2955<p>
2956The optional "align" argument specifies the alignment of the operation
2957(that is, the alignment of the memory address). A value of 0 or an
2958omitted "align" argument means that the operation has the preferential
2959alignment for the target. It is the responsibility of the code emitter
2960to ensure that the alignment information is correct. Overestimating
2961the alignment results in an undefined behavior. Underestimating the
2962alignment may produce less efficient code. An alignment of 1 is always
2963safe.
2964</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2965<h5>Semantics:</h5>
2966<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2967at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2968<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2969<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]2970 store i32 3, i32* %ptr <i>; yields {void}</i>
2971 %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]2972</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2973</div>
2974
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2975<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2976<div class="doc_subsubsection">
2977 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2978</div>
2979
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2980<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2981<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2982<pre>
2983 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2984</pre>
2985
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2986<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2987
2988<p>
2989The '<tt>getelementptr</tt>' instruction is used to get the address of a
2990subelement of an aggregate data structure.</p>
2991
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2992<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2993
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2994<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2995elements of the aggregate object to index to. The actual types of the arguments
2996provided depend on the type of the first pointer argument. The
2997'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2998levels 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]2999structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3000into an array or pointer, only integers of 32 or 64 bits are allowed, and will
3001be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3002
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3003<p>For example, let's consider a C code fragment and how it gets
3004compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3005
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3006<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3007<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3008struct RT {
3009 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3010 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3011 char C;
3012};
3013struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3014 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3015 double Y;
3016 struct RT Z;
3017};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3018
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]3019int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3020 return &amp;s[1].Z.B[5][13];
3021}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3022</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3023</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3024
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3025<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3026
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3027<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3028<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3029%RT = type { i8 , [10 x [20 x i32]], i8 }
3030%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3031
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3032define i32* %foo(%ST* %s) {
3033entry:
3034 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3035 ret i32* %reg
3036}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3037</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3038</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3039
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3040<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3041
3042<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3043on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3044and <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]3045<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]3046to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]3047<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3048
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3049<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]3050type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3051}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3052the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3053i8 }</tt>' type, another structure. The third index indexes into the second
3054element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3055array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3056'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3057to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3058
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3059<p>Note that it is perfectly legal to index partially through a
3060structure, returning a pointer to an inner element. Because of this,
3061the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3062
3063<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3064 define i32* %foo(%ST* %s) {
3065 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3066 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3067 %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]3068 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3069 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3070 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3071 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3072</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3073
3074<p>Note that it is undefined to access an array out of bounds: array and
3075pointer indexes must always be within the defined bounds of the array type.
3076The one exception for this rules is zero length arrays. These arrays are
3077defined to be accessible as variable length arrays, which requires access
3078beyond the zero'th element.</p>
3079
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3080<p>The getelementptr instruction is often confusing. For some more insight
3081into how it works, see <a href="GetElementPtr.html">the getelementptr
3082FAQ</a>.</p>
3083
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3084<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3085
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3086<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3087 <i>; yields [12 x i8]*:aptr</i>
3088 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3089</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3090</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3091
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3092<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3093<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3094</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3095<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3096<p>The instructions in this category are the conversion instructions (casting)
3097which all take a single operand and a type. They perform various bit conversions
3098on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3099</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3100
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3101<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3102<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3103 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3104</div>
3105<div class="doc_text">
3106
3107<h5>Syntax:</h5>
3108<pre>
3109 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3110</pre>
3111
3112<h5>Overview:</h5>
3113<p>
3114The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3115</p>
3116
3117<h5>Arguments:</h5>
3118<p>
3119The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3120be 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]3121and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3122type. The bit size of <tt>value</tt> must be larger than the bit size of
3123<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3124
3125<h5>Semantics:</h5>
3126<p>
3127The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3128and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3129larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3130It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3131
3132<h5>Example:</h5>
3133<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3134 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3135 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3136 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3137</pre>
3138</div>
3139
3140<!-- _______________________________________________________________________ -->
3141<div class="doc_subsubsection">
3142 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3143</div>
3144<div class="doc_text">
3145
3146<h5>Syntax:</h5>
3147<pre>
3148 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3149</pre>
3150
3151<h5>Overview:</h5>
3152<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3153<tt>ty2</tt>.</p>
3154
3155
3156<h5>Arguments:</h5>
3157<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]3158<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3159also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3160<tt>value</tt> must be smaller than the bit size of the destination type,
3161<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3162
3163<h5>Semantics:</h5>
3164<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]3165bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3166
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3167<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]3168
3169<h5>Example:</h5>
3170<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3171 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3172 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3173</pre>
3174</div>
3175
3176<!-- _______________________________________________________________________ -->
3177<div class="doc_subsubsection">
3178 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3179</div>
3180<div class="doc_text">
3181
3182<h5>Syntax:</h5>
3183<pre>
3184 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3185</pre>
3186
3187<h5>Overview:</h5>
3188<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3189
3190<h5>Arguments:</h5>
3191<p>
3192The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3193<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3194also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3195<tt>value</tt> must be smaller than the bit size of the destination type,
3196<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3197
3198<h5>Semantics:</h5>
3199<p>
3200The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3201bit (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]3202the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3203
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3204<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]3205
3206<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3207<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3208 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3209 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3210</pre>
3211</div>
3212
3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3215 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3216</div>
3217
3218<div class="doc_text">
3219
3220<h5>Syntax:</h5>
3221
3222<pre>
3223 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3224</pre>
3225
3226<h5>Overview:</h5>
3227<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3228<tt>ty2</tt>.</p>
3229
3230
3231<h5>Arguments:</h5>
3232<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3233 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3234cast it to. The size of <tt>value</tt> must be larger than the size of
3235<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3236<i>no-op cast</i>.</p>
3237
3238<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3239<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3240<a href="#t_floating">floating point</a> type to a smaller
3241<a href="#t_floating">floating point</a> type. If the value cannot fit within
3242the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3243
3244<h5>Example:</h5>
3245<pre>
3246 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3247 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3248</pre>
3249</div>
3250
3251<!-- _______________________________________________________________________ -->
3252<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3253 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3254</div>
3255<div class="doc_text">
3256
3257<h5>Syntax:</h5>
3258<pre>
3259 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3260</pre>
3261
3262<h5>Overview:</h5>
3263<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3264floating point value.</p>
3265
3266<h5>Arguments:</h5>
3267<p>The '<tt>fpext</tt>' instruction takes a
3268<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3269and a <a href="#t_floating">floating point</a> type to cast it to. The source
3270type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3271
3272<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3273<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3274<a href="#t_floating">floating point</a> type to a larger
3275<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3276used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3277<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]3278
3279<h5>Example:</h5>
3280<pre>
3281 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3282 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3283</pre>
3284</div>
3285
3286<!-- _______________________________________________________________________ -->
3287<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3288 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3289</div>
3290<div class="doc_text">
3291
3292<h5>Syntax:</h5>
3293<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3294 &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]3295</pre>
3296
3297<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3298<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3299unsigned integer equivalent of type <tt>ty2</tt>.
3300</p>
3301
3302<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3303<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]3304scalar or vector <a href="#t_floating">floating point</a> value, and a type
3305to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3306type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3307vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3308
3309<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3310<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3311<a href="#t_floating">floating point</a> operand into the nearest (rounding
3312towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3313the results are undefined.</p>
3314
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3315<h5>Example:</h5>
3316<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3317 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3318 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3319 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3320</pre>
3321</div>
3322
3323<!-- _______________________________________________________________________ -->
3324<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3325 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3326</div>
3327<div class="doc_text">
3328
3329<h5>Syntax:</h5>
3330<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3331 &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]3332</pre>
3333
3334<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3335<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3336<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]3337</p>
3338
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3339<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3340<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]3341scalar or vector <a href="#t_floating">floating point</a> value, and a type
3342to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3343type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3344vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3345
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3346<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3347<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3348<a href="#t_floating">floating point</a> operand into the nearest (rounding
3349towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3350the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3351
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3352<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3353<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3354 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3355 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3356 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3357</pre>
3358</div>
3359
3360<!-- _______________________________________________________________________ -->
3361<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3362 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3363</div>
3364<div class="doc_text">
3365
3366<h5>Syntax:</h5>
3367<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3368 &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]3369</pre>
3370
3371<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3372<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3373integer and converts that value to the <tt>ty2</tt> type.</p>
3374
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3375<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3376<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3377scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3378to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3379type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3380floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3381
3382<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3383<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3384integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3385the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3386
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3387<h5>Example:</h5>
3388<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3389 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3390 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3391</pre>
3392</div>
3393
3394<!-- _______________________________________________________________________ -->
3395<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3396 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3397</div>
3398<div class="doc_text">
3399
3400<h5>Syntax:</h5>
3401<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3402 &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]3403</pre>
3404
3405<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3406<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3407integer and converts that value to the <tt>ty2</tt> type.</p>
3408
3409<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3410<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3411scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3412to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3413type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3414floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3415
3416<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3417<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3418integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3419the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3420
3421<h5>Example:</h5>
3422<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3423 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3424 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3425</pre>
3426</div>
3427
3428<!-- _______________________________________________________________________ -->
3429<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3430 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3431</div>
3432<div class="doc_text">
3433
3434<h5>Syntax:</h5>
3435<pre>
3436 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3437</pre>
3438
3439<h5>Overview:</h5>
3440<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3441the integer type <tt>ty2</tt>.</p>
3442
3443<h5>Arguments:</h5>
3444<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3445must 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]3446<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3447
3448<h5>Semantics:</h5>
3449<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3450<tt>ty2</tt> by interpreting the pointer value as an integer and either
3451truncating or zero extending that value to the size of the integer type. If
3452<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3453<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]3454are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3455change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3456
3457<h5>Example:</h5>
3458<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3459 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3460 %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]3461</pre>
3462</div>
3463
3464<!-- _______________________________________________________________________ -->
3465<div class="doc_subsubsection">
3466 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3467</div>
3468<div class="doc_text">
3469
3470<h5>Syntax:</h5>
3471<pre>
3472 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3473</pre>
3474
3475<h5>Overview:</h5>
3476<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3477a pointer type, <tt>ty2</tt>.</p>
3478
3479<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3480<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3481value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3482<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3483
3484<h5>Semantics:</h5>
3485<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3486<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3487the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3488size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3489the size of a pointer then a zero extension is done. If they are the same size,
3490nothing is done (<i>no-op cast</i>).</p>
3491
3492<h5>Example:</h5>
3493<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3494 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3495 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3496 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3497</pre>
3498</div>
3499
3500<!-- _______________________________________________________________________ -->
3501<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3502 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3503</div>
3504<div class="doc_text">
3505
3506<h5>Syntax:</h5>
3507<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3508 &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]3509</pre>
3510
3511<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3512<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3513<tt>ty2</tt> without changing any bits.</p>
3514
3515<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3516<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3517a first class value, and a type to cast it to, which must also be a <a
3518 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3519and the destination type, <tt>ty2</tt>, must be identical. If the source
3520type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3521
3522<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3523<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3524<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3525this conversion. The conversion is done as if the <tt>value</tt> had been
3526stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3527converted to other pointer types with this instruction. To convert pointers to
3528other types, use the <a href="#i_inttoptr">inttoptr</a> or
3529<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3530
3531<h5>Example:</h5>
3532<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3533 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3534 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3535 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3536</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3537</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3538
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3539<!-- ======================================================================= -->
3540<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3541<div class="doc_text">
3542<p>The instructions in this category are the "miscellaneous"
3543instructions, which defy better classification.</p>
3544</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3545
3546<!-- _______________________________________________________________________ -->
3547<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3548</div>
3549<div class="doc_text">
3550<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3551<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]3552</pre>
3553<h5>Overview:</h5>
3554<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3555of its two integer operands.</p>
3556<h5>Arguments:</h5>
3557<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3558the condition code indicating the kind of comparison to perform. It is not
3559a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3560<ol>
3561 <li><tt>eq</tt>: equal</li>
3562 <li><tt>ne</tt>: not equal </li>
3563 <li><tt>ugt</tt>: unsigned greater than</li>
3564 <li><tt>uge</tt>: unsigned greater or equal</li>
3565 <li><tt>ult</tt>: unsigned less than</li>
3566 <li><tt>ule</tt>: unsigned less or equal</li>
3567 <li><tt>sgt</tt>: signed greater than</li>
3568 <li><tt>sge</tt>: signed greater or equal</li>
3569 <li><tt>slt</tt>: signed less than</li>
3570 <li><tt>sle</tt>: signed less or equal</li>
3571</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3572<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3573<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3574<h5>Semantics:</h5>
3575<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3576the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3577yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3578<ol>
3579 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3580 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3581 </li>
3582 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3583 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3584 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3585 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3586 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3587 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3588 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3589 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3590 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3591 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3592 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3593 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3594 <li><tt>sge</tt>: interprets the operands as signed values and yields
3595 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3596 <li><tt>slt</tt>: interprets the operands as signed values and yields
3597 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3598 <li><tt>sle</tt>: interprets the operands as signed values and yields
3599 <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]3600</ol>
3601<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3602values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3603
3604<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3605<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3606 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3607 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3608 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3609 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3610 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3611</pre>
3612</div>
3613
3614<!-- _______________________________________________________________________ -->
3615<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3616</div>
3617<div class="doc_text">
3618<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3619<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]3620</pre>
3621<h5>Overview:</h5>
3622<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3623of its floating point operands.</p>
3624<h5>Arguments:</h5>
3625<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3626the condition code indicating the kind of comparison to perform. It is not
3627a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3628<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3629 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3630 <li><tt>oeq</tt>: ordered and equal</li>
3631 <li><tt>ogt</tt>: ordered and greater than </li>
3632 <li><tt>oge</tt>: ordered and greater than or equal</li>
3633 <li><tt>olt</tt>: ordered and less than </li>
3634 <li><tt>ole</tt>: ordered and less than or equal</li>
3635 <li><tt>one</tt>: ordered and not equal</li>
3636 <li><tt>ord</tt>: ordered (no nans)</li>
3637 <li><tt>ueq</tt>: unordered or equal</li>
3638 <li><tt>ugt</tt>: unordered or greater than </li>
3639 <li><tt>uge</tt>: unordered or greater than or equal</li>
3640 <li><tt>ult</tt>: unordered or less than </li>
3641 <li><tt>ule</tt>: unordered or less than or equal</li>
3642 <li><tt>une</tt>: unordered or not equal</li>
3643 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3644 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3645</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3646<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3647<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3648<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3649<a href="#t_floating">floating point</a> typed. They must have identical
3650types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3651<h5>Semantics:</h5>
3652<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3653the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3654yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3655<ol>
3656 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3657 <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]3658 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3659 <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]3660 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3661 <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]3662 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3663 <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]3664 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3665 <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]3666 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3667 <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]3668 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3669 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3670 <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]3671 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3672 <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]3673 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3674 <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]3675 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3676 <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]3677 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3678 <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]3679 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3680 <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]3681 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3682 <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]3683 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3684</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3685
3686<h5>Example:</h5>
3687<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3688 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3689 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3690 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3691</pre>
3692</div>
3693
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3696Instruction</a> </div>
3697<div class="doc_text">
3698<h5>Syntax:</h5>
3699<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3700<h5>Overview:</h5>
3701<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3702the SSA graph representing the function.</p>
3703<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3704<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3705field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3706as arguments, with one pair for each predecessor basic block of the
3707current block. Only values of <a href="#t_firstclass">first class</a>
3708type may be used as the value arguments to the PHI node. Only labels
3709may be used as the label arguments.</p>
3710<p>There must be no non-phi instructions between the start of a basic
3711block and the PHI instructions: i.e. PHI instructions must be first in
3712a basic block.</p>
3713<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3714<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3715specified by the pair corresponding to the predecessor basic block that executed
3716just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3717<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3718<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]3719</div>
3720
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3721<!-- _______________________________________________________________________ -->
3722<div class="doc_subsubsection">
3723 <a name="i_select">'<tt>select</tt>' Instruction</a>
3724</div>
3725
3726<div class="doc_text">
3727
3728<h5>Syntax:</h5>
3729
3730<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3731 &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]3732</pre>
3733
3734<h5>Overview:</h5>
3735
3736<p>
3737The '<tt>select</tt>' instruction is used to choose one value based on a
3738condition, without branching.
3739</p>
3740
3741
3742<h5>Arguments:</h5>
3743
3744<p>
3745The '<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.
3746</p>
3747
3748<h5>Semantics:</h5>
3749
3750<p>
3751If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3752value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3753</p>
3754
3755<h5>Example:</h5>
3756
3757<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3758 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3759</pre>
3760</div>
3761
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3762
3763<!-- _______________________________________________________________________ -->
3764<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3765 <a name="i_call">'<tt>call</tt>' Instruction</a>
3766</div>
3767
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3768<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3769
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3770<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3771<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3772 &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]3773</pre>
3774
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3775<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3776
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3777<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3778
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3779<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3780
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3781<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3782
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3783<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3784 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3785 <p>The optional "tail" marker indicates whether the callee function accesses
3786 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3787 function call is eligible for tail call optimization. Note that calls may
3788 be marked "tail" even if they do not occur before a <a
3789 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3790 </li>
3791 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3792 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3793 convention</a> the call should use. If none is specified, the call defaults
3794 to using C calling conventions.
3795 </li>
3796 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3797 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3798 the type of the return value. Functions that return no value are marked
3799 <tt><a href="#t_void">void</a></tt>.</p>
3800 </li>
3801 <li>
3802 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3803 value being invoked. The argument types must match the types implied by
3804 this signature. This type can be omitted if the function is not varargs
3805 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3806 </li>
3807 <li>
3808 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3809 be invoked. In most cases, this is a direct function invocation, but
3810 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3811 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3812 </li>
3813 <li>
3814 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3815 function signature argument types. All arguments must be of
3816 <a href="#t_firstclass">first class</a> type. If the function signature
3817 indicates the function accepts a variable number of arguments, the extra
3818 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3819 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3820</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3822<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3823
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3824<p>The '<tt>call</tt>' instruction is used to cause control flow to
3825transfer to a specified function, with its incoming arguments bound to
3826the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3827instruction in the called function, control flow continues with the
3828instruction after the function call, and the return value of the
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]3829function is bound to the result argument. If the callee returns multiple
3830values then the return values of the function are only accessible through
3831the '<tt><a href="#i_getresult">getresult</a></tt>' instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3832
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3833<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3834
3835<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3836 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]3837 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
3838 %X = tail call i32 @foo() <i>; yields i32</i>
3839 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
3840 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3841
3842 %struct.A = type { i32, i8 }
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]3843 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
3844 %gr = getresult %struct.A %r, 0 <i>; yields i32</i>
3845 %gr1 = getresult %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3846</pre>
3847
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3848</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3849
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3850<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3851<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3852 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3853</div>
3854
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3855<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3856
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3857<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3858
3859<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3860 &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]3861</pre>
3862
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3863<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3864
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3865<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3866the "variable argument" area of a function call. It is used to implement the
3867<tt>va_arg</tt> macro in C.</p>
3868
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3869<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3870
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3871<p>This instruction takes a <tt>va_list*</tt> value and the type of
3872the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3873increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3874actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3875
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3876<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3877
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3878<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3879type from the specified <tt>va_list</tt> and causes the
3880<tt>va_list</tt> to point to the next argument. For more information,
3881see the variable argument handling <a href="#int_varargs">Intrinsic
3882Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3883
3884<p>It is legal for this instruction to be called in a function which does not
3885take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3886function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3887
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3888<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3889href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3890argument.</p>
3891
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3892<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3893
3894<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3895
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3896</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3897
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3898<!-- _______________________________________________________________________ -->
3899<div class="doc_subsubsection">
3900 <a name="i_getresult">'<tt>getresult</tt>' Instruction</a>
3901</div>
3902
3903<div class="doc_text">
3904
3905<h5>Syntax:</h5>
3906<pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]3907 &lt;resultval&gt; = getresult &lt;type&gt; &lt;retval&gt;, &lt;index&gt;
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3908</pre>
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]3909
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3910<h5>Overview:</h5>
3911
3912<p> The '<tt>getresult</tt>' instruction is used to extract individual values
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]3913from a '<tt><a href="#i_call">call</a></tt>'
3914or '<tt><a href="#i_invoke">invoke</a></tt>' instruction that returns multiple
3915results.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3916
3917<h5>Arguments:</h5>
3918
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]3919<p>The '<tt>getresult</tt>' instruction takes a call or invoke value as its
3920first argument. The value must have <a href="#t_struct">structure type</a>.
3921The second argument is an unsigned index value which must be in range for
3922the number of values returned by the call.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3923
3924<h5>Semantics:</h5>
3925
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]3926<p>The '<tt>getresult</tt>' instruction extracts the element identified by
3927'<tt>index</tt>' from the aggregate value.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3928
3929<h5>Example:</h5>
3930
3931<pre>
3932 %struct.A = type { i32, i8 }
3933
3934 %r = call %struct.A @foo()
Chris Lattner141b6132008-03-21 17:20:51 +0000[diff] [blame]3935 %gr = getresult %struct.A %r, 0 <i>; yields i32:%gr</i>
3936 %gr1 = getresult %struct.A %r, 1 <i>; yields i8:%gr1</i>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]3937 add i32 %gr, 42
3938 add i8 %gr1, 41
3939</pre>
3940
3941</div>
3942
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3943<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3944<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3945<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3946
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3947<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3948
3949<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3950well known names and semantics and are required to follow certain restrictions.
3951Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3952language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]3953adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3954
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3955<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3956prefix is reserved in LLVM for intrinsic names; thus, function names may not
3957begin with this prefix. Intrinsic functions must always be external functions:
3958you cannot define the body of intrinsic functions. Intrinsic functions may
3959only be used in call or invoke instructions: it is illegal to take the address
3960of an intrinsic function. Additionally, because intrinsic functions are part
3961of the LLVM language, it is required if any are added that they be documented
3962here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3963
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3964<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3965a family of functions that perform the same operation but on different data
3966types. Because LLVM can represent over 8 million different integer types,
3967overloading is used commonly to allow an intrinsic function to operate on any
3968integer type. One or more of the argument types or the result type can be
3969overloaded to accept any integer type. Argument types may also be defined as
3970exactly matching a previous argument's type or the result type. This allows an
3971intrinsic function which accepts multiple arguments, but needs all of them to
3972be of the same type, to only be overloaded with respect to a single argument or
3973the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3974
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3975<p>Overloaded intrinsics will have the names of its overloaded argument types
3976encoded into its function name, each preceded by a period. Only those types
3977which are overloaded result in a name suffix. Arguments whose type is matched
3978against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3979take an integer of any width and returns an integer of exactly the same integer
3980width. This leads to a family of functions such as
3981<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3982Only one type, the return type, is overloaded, and only one type suffix is
3983required. Because the argument's type is matched against the return type, it
3984does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3985
3986<p>To learn how to add an intrinsic function, please see the
3987<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3988</p>
3989
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3990</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3991
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3992<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3993<div class="doc_subsection">
3994 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3995</div>
3996
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3997<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3998
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3999<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]4000 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4001intrinsic functions. These functions are related to the similarly
4002named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4003
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4004<p>All of these functions operate on arguments that use a
4005target-specific value type "<tt>va_list</tt>". The LLVM assembly
4006language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4007transformations should be prepared to handle these functions regardless of
4008the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4009
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]4010<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]4011instruction and the variable argument handling intrinsic functions are
4012used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4013
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4014<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4015<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4016define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4017 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4018 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4019 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4020 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4021
4022 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4023 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4024
4025 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4026 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4027 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4028 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4029 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4030
4031 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4032 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4033 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4034}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]4035
4036declare void @llvm.va_start(i8*)
4037declare void @llvm.va_copy(i8*, i8*)
4038declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4039</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4040</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4041
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]4042</div>
4043
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4044<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4045<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4046 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4047</div>
4048
4049
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4050<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4051<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4052<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4053<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4054<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
4055<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4056href="#i_va_arg">va_arg</a></tt>.</p>
4057
4058<h5>Arguments:</h5>
4059
4060<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
4061
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4062<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4063
4064<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
4065macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4066<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]4067<tt>va_arg</tt> will produce the first variable argument passed to the function.
4068Unlike 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]4069last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4070
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4071</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4072
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4073<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4074<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4075 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4076</div>
4077
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4078<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4079<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4080<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4081<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4082
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4083<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4084which 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]4085or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4086
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4087<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4088
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4089<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]4090
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4091<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4092
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4093<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]4094macro available in C. In a target-dependent way, it destroys the
4095<tt>va_list</tt> element to which the argument points. Calls to <a
4096href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4097<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4098<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4099
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4100</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4101
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4102<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4103<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4104 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4105</div>
4106
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4107<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4108
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4109<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4110
4111<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4112 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4113</pre>
4114
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4115<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4116
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4117<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4118from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4119
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4120<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4121
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4122<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]4123The 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]4124
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4125
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4126<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4127
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4128<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4129macro available in C. In a target-dependent way, it copies the source
4130<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4131intrinsic is necessary because the <tt><a href="#int_va_start">
4132llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4133example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4134
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4135</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4136
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4137<!-- ======================================================================= -->
4138<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4139 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4140</div>
4141
4142<div class="doc_text">
4143
4144<p>
4145LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4146Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4147These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4148stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4149href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4150Front-ends for type-safe garbage collected languages should generate these
4151intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4152href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4153</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4154
4155<p>The garbage collection intrinsics only operate on objects in the generic
4156 address space (address space zero).</p>
4157
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4158</div>
4159
4160<!-- _______________________________________________________________________ -->
4161<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4162 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4163</div>
4164
4165<div class="doc_text">
4166
4167<h5>Syntax:</h5>
4168
4169<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4170 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4171</pre>
4172
4173<h5>Overview:</h5>
4174
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4175<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]4176the code generator, and allows some metadata to be associated with it.</p>
4177
4178<h5>Arguments:</h5>
4179
4180<p>The first argument specifies the address of a stack object that contains the
4181root pointer. The second pointer (which must be either a constant or a global
4182value address) contains the meta-data to be associated with the root.</p>
4183
4184<h5>Semantics:</h5>
4185
4186<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4187location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4188the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4189intrinsic may only be used in a function which <a href="#gc">specifies a GC
4190algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4191
4192</div>
4193
4194
4195<!-- _______________________________________________________________________ -->
4196<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4197 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4198</div>
4199
4200<div class="doc_text">
4201
4202<h5>Syntax:</h5>
4203
4204<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4205 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4206</pre>
4207
4208<h5>Overview:</h5>
4209
4210<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4211locations, allowing garbage collector implementations that require read
4212barriers.</p>
4213
4214<h5>Arguments:</h5>
4215
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4216<p>The second argument is the address to read from, which should be an address
4217allocated from the garbage collector. The first object is a pointer to the
4218start of the referenced object, if needed by the language runtime (otherwise
4219null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4220
4221<h5>Semantics:</h5>
4222
4223<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4224instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4225garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4226may only be used in a function which <a href="#gc">specifies a GC
4227algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4228
4229</div>
4230
4231
4232<!-- _______________________________________________________________________ -->
4233<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4234 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4235</div>
4236
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240
4241<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4242 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4243</pre>
4244
4245<h5>Overview:</h5>
4246
4247<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4248locations, allowing garbage collector implementations that require write
4249barriers (such as generational or reference counting collectors).</p>
4250
4251<h5>Arguments:</h5>
4252
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4253<p>The first argument is the reference to store, the second is the start of the
4254object to store it to, and the third is the address of the field of Obj to
4255store to. If the runtime does not require a pointer to the object, Obj may be
4256null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4257
4258<h5>Semantics:</h5>
4259
4260<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4261instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4262garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4263may only be used in a function which <a href="#gc">specifies a GC
4264algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4265
4266</div>
4267
4268
4269
4270<!-- ======================================================================= -->
4271<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4272 <a name="int_codegen">Code Generator Intrinsics</a>
4273</div>
4274
4275<div class="doc_text">
4276<p>
4277These intrinsics are provided by LLVM to expose special features that may only
4278be implemented with code generator support.
4279</p>
4280
4281</div>
4282
4283<!-- _______________________________________________________________________ -->
4284<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4285 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4286</div>
4287
4288<div class="doc_text">
4289
4290<h5>Syntax:</h5>
4291<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4292 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4293</pre>
4294
4295<h5>Overview:</h5>
4296
4297<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4298The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4299target-specific value indicating the return address of the current function
4300or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4301</p>
4302
4303<h5>Arguments:</h5>
4304
4305<p>
4306The argument to this intrinsic indicates which function to return the address
4307for. Zero indicates the calling function, one indicates its caller, etc. The
4308argument is <b>required</b> to be a constant integer value.
4309</p>
4310
4311<h5>Semantics:</h5>
4312
4313<p>
4314The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4315the return address of the specified call frame, or zero if it cannot be
4316identified. The value returned by this intrinsic is likely to be incorrect or 0
4317for arguments other than zero, so it should only be used for debugging purposes.
4318</p>
4319
4320<p>
4321Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4322aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4323source-language caller.
4324</p>
4325</div>
4326
4327
4328<!-- _______________________________________________________________________ -->
4329<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4330 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4331</div>
4332
4333<div class="doc_text">
4334
4335<h5>Syntax:</h5>
4336<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4337 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4338</pre>
4339
4340<h5>Overview:</h5>
4341
4342<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4343The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4344target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4345</p>
4346
4347<h5>Arguments:</h5>
4348
4349<p>
4350The argument to this intrinsic indicates which function to return the frame
4351pointer for. Zero indicates the calling function, one indicates its caller,
4352etc. The argument is <b>required</b> to be a constant integer value.
4353</p>
4354
4355<h5>Semantics:</h5>
4356
4357<p>
4358The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4359the frame address of the specified call frame, or zero if it cannot be
4360identified. The value returned by this intrinsic is likely to be incorrect or 0
4361for arguments other than zero, so it should only be used for debugging purposes.
4362</p>
4363
4364<p>
4365Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4366aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4367source-language caller.
4368</p>
4369</div>
4370
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4371<!-- _______________________________________________________________________ -->
4372<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4373 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4374</div>
4375
4376<div class="doc_text">
4377
4378<h5>Syntax:</h5>
4379<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4380 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4381</pre>
4382
4383<h5>Overview:</h5>
4384
4385<p>
4386The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4387the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4388<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4389features like scoped automatic variable sized arrays in C99.
4390</p>
4391
4392<h5>Semantics:</h5>
4393
4394<p>
4395This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4396href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4397<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4398<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4399state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4400practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4401that were allocated after the <tt>llvm.stacksave</tt> was executed.
4402</p>
4403
4404</div>
4405
4406<!-- _______________________________________________________________________ -->
4407<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4408 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4409</div>
4410
4411<div class="doc_text">
4412
4413<h5>Syntax:</h5>
4414<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4415 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4416</pre>
4417
4418<h5>Overview:</h5>
4419
4420<p>
4421The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4422the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4423href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4424useful for implementing language features like scoped automatic variable sized
4425arrays in C99.
4426</p>
4427
4428<h5>Semantics:</h5>
4429
4430<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4431See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4432</p>
4433
4434</div>
4435
4436
4437<!-- _______________________________________________________________________ -->
4438<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4439 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4440</div>
4441
4442<div class="doc_text">
4443
4444<h5>Syntax:</h5>
4445<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4446 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]4447</pre>
4448
4449<h5>Overview:</h5>
4450
4451
4452<p>
4453The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4454a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4455no
4456effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4457characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4458</p>
4459
4460<h5>Arguments:</h5>
4461
4462<p>
4463<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4464determining if the fetch should be for a read (0) or write (1), and
4465<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4466locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4467<tt>locality</tt> arguments must be constant integers.
4468</p>
4469
4470<h5>Semantics:</h5>
4471
4472<p>
4473This intrinsic does not modify the behavior of the program. In particular,
4474prefetches cannot trap and do not produce a value. On targets that support this
4475intrinsic, the prefetch can provide hints to the processor cache for better
4476performance.
4477</p>
4478
4479</div>
4480
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4481<!-- _______________________________________________________________________ -->
4482<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4483 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4484</div>
4485
4486<div class="doc_text">
4487
4488<h5>Syntax:</h5>
4489<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4490 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4491</pre>
4492
4493<h5>Overview:</h5>
4494
4495
4496<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4497The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4498(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4499code to simulators and other tools. The method is target specific, but it is
4500expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4501The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4502after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4503optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4504correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4505</p>
4506
4507<h5>Arguments:</h5>
4508
4509<p>
4510<tt>id</tt> is a numerical id identifying the marker.
4511</p>
4512
4513<h5>Semantics:</h5>
4514
4515<p>
4516This intrinsic does not modify the behavior of the program. Backends that do not
4517support this intrinisic may ignore it.
4518</p>
4519
4520</div>
4521
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4522<!-- _______________________________________________________________________ -->
4523<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4524 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4525</div>
4526
4527<div class="doc_text">
4528
4529<h5>Syntax:</h5>
4530<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4531 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4532</pre>
4533
4534<h5>Overview:</h5>
4535
4536
4537<p>
4538The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4539counter register (or similar low latency, high accuracy clocks) on those targets
4540that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4541As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4542should only be used for small timings.
4543</p>
4544
4545<h5>Semantics:</h5>
4546
4547<p>
4548When directly supported, reading the cycle counter should not modify any memory.
4549Implementations are allowed to either return a application specific value or a
4550system wide value. On backends without support, this is lowered to a constant 0.
4551</p>
4552
4553</div>
4554
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4555<!-- ======================================================================= -->
4556<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4557 <a name="int_libc">Standard C Library Intrinsics</a>
4558</div>
4559
4560<div class="doc_text">
4561<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4562LLVM provides intrinsics for a few important standard C library functions.
4563These intrinsics allow source-language front-ends to pass information about the
4564alignment of the pointer arguments to the code generator, providing opportunity
4565for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4566</p>
4567
4568</div>
4569
4570<!-- _______________________________________________________________________ -->
4571<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4572 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4573</div>
4574
4575<div class="doc_text">
4576
4577<h5>Syntax:</h5>
4578<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4579 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4580 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4581 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4582 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4583</pre>
4584
4585<h5>Overview:</h5>
4586
4587<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4588The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4589location to the destination location.
4590</p>
4591
4592<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4593Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4594intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4595</p>
4596
4597<h5>Arguments:</h5>
4598
4599<p>
4600The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4601the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4602specifying the number of bytes to copy, and the fourth argument is the alignment
4603of the source and destination locations.
4604</p>
4605
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4606<p>
4607If 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]4608the caller guarantees that both the source and destination pointers are aligned
4609to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4610</p>
4611
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4612<h5>Semantics:</h5>
4613
4614<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4615The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4616location to the destination location, which are not allowed to overlap. It
4617copies "len" bytes of memory over. If the argument is known to be aligned to
4618some boundary, this can be specified as the fourth argument, otherwise it should
4619be set to 0 or 1.
4620</p>
4621</div>
4622
4623
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4624<!-- _______________________________________________________________________ -->
4625<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4626 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4627</div>
4628
4629<div class="doc_text">
4630
4631<h5>Syntax:</h5>
4632<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4633 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4634 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4635 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4636 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4637</pre>
4638
4639<h5>Overview:</h5>
4640
4641<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4642The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4643location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]4644'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4645</p>
4646
4647<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4648Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4649intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4650</p>
4651
4652<h5>Arguments:</h5>
4653
4654<p>
4655The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4656the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4657specifying the number of bytes to copy, and the fourth argument is the alignment
4658of the source and destination locations.
4659</p>
4660
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4661<p>
4662If 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]4663the caller guarantees that the source and destination pointers are aligned to
4664that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4665</p>
4666
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4667<h5>Semantics:</h5>
4668
4669<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4670The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4671location to the destination location, which may overlap. It
4672copies "len" bytes of memory over. If the argument is known to be aligned to
4673some boundary, this can be specified as the fourth argument, otherwise it should
4674be set to 0 or 1.
4675</p>
4676</div>
4677
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4678
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4679<!-- _______________________________________________________________________ -->
4680<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4681 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4682</div>
4683
4684<div class="doc_text">
4685
4686<h5>Syntax:</h5>
4687<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4688 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4689 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4690 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4691 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4692</pre>
4693
4694<h5>Overview:</h5>
4695
4696<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4697The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4698byte value.
4699</p>
4700
4701<p>
4702Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4703does not return a value, and takes an extra alignment argument.
4704</p>
4705
4706<h5>Arguments:</h5>
4707
4708<p>
4709The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4710byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4711argument specifying the number of bytes to fill, and the fourth argument is the
4712known alignment of destination location.
4713</p>
4714
4715<p>
4716If 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]4717the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4718</p>
4719
4720<h5>Semantics:</h5>
4721
4722<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4723The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4724the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4725destination location. If the argument is known to be aligned to some boundary,
4726this can be specified as the fourth argument, otherwise it should be set to 0 or
47271.
4728</p>
4729</div>
4730
4731
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4732<!-- _______________________________________________________________________ -->
4733<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4734 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4735</div>
4736
4737<div class="doc_text">
4738
4739<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4740<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]4741floating point or vector of floating point type. Not all targets support all
4742types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4743<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4744 declare float @llvm.sqrt.f32(float %Val)
4745 declare double @llvm.sqrt.f64(double %Val)
4746 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4747 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4748 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4749</pre>
4750
4751<h5>Overview:</h5>
4752
4753<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4754The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4755returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4756<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +0000[diff] [blame]4757negative numbers other than -0.0 (which allows for better optimization, because
4758there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4759defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4760</p>
4761
4762<h5>Arguments:</h5>
4763
4764<p>
4765The argument and return value are floating point numbers of the same type.
4766</p>
4767
4768<h5>Semantics:</h5>
4769
4770<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]4771This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4772floating point number.
4773</p>
4774</div>
4775
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4776<!-- _______________________________________________________________________ -->
4777<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4778 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4779</div>
4780
4781<div class="doc_text">
4782
4783<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4784<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]4785floating point or vector of floating point type. Not all targets support all
4786types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4787<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4788 declare float @llvm.powi.f32(float %Val, i32 %power)
4789 declare double @llvm.powi.f64(double %Val, i32 %power)
4790 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4791 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4792 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4793</pre>
4794
4795<h5>Overview:</h5>
4796
4797<p>
4798The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4799specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4800multiplications is not defined. When a vector of floating point type is
4801used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4802</p>
4803
4804<h5>Arguments:</h5>
4805
4806<p>
4807The second argument is an integer power, and the first is a value to raise to
4808that power.
4809</p>
4810
4811<h5>Semantics:</h5>
4812
4813<p>
4814This function returns the first value raised to the second power with an
4815unspecified sequence of rounding operations.</p>
4816</div>
4817
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4818<!-- _______________________________________________________________________ -->
4819<div class="doc_subsubsection">
4820 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4821</div>
4822
4823<div class="doc_text">
4824
4825<h5>Syntax:</h5>
4826<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4827floating point or vector of floating point type. Not all targets support all
4828types however.
4829<pre>
4830 declare float @llvm.sin.f32(float %Val)
4831 declare double @llvm.sin.f64(double %Val)
4832 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4833 declare fp128 @llvm.sin.f128(fp128 %Val)
4834 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4835</pre>
4836
4837<h5>Overview:</h5>
4838
4839<p>
4840The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4841</p>
4842
4843<h5>Arguments:</h5>
4844
4845<p>
4846The argument and return value are floating point numbers of the same type.
4847</p>
4848
4849<h5>Semantics:</h5>
4850
4851<p>
4852This function returns the sine of the specified operand, returning the
4853same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4854conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4855</div>
4856
4857<!-- _______________________________________________________________________ -->
4858<div class="doc_subsubsection">
4859 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4860</div>
4861
4862<div class="doc_text">
4863
4864<h5>Syntax:</h5>
4865<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4866floating point or vector of floating point type. Not all targets support all
4867types however.
4868<pre>
4869 declare float @llvm.cos.f32(float %Val)
4870 declare double @llvm.cos.f64(double %Val)
4871 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4872 declare fp128 @llvm.cos.f128(fp128 %Val)
4873 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4874</pre>
4875
4876<h5>Overview:</h5>
4877
4878<p>
4879The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4880</p>
4881
4882<h5>Arguments:</h5>
4883
4884<p>
4885The argument and return value are floating point numbers of the same type.
4886</p>
4887
4888<h5>Semantics:</h5>
4889
4890<p>
4891This function returns the cosine of the specified operand, returning the
4892same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4893conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4894</div>
4895
4896<!-- _______________________________________________________________________ -->
4897<div class="doc_subsubsection">
4898 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4899</div>
4900
4901<div class="doc_text">
4902
4903<h5>Syntax:</h5>
4904<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4905floating point or vector of floating point type. Not all targets support all
4906types however.
4907<pre>
4908 declare float @llvm.pow.f32(float %Val, float %Power)
4909 declare double @llvm.pow.f64(double %Val, double %Power)
4910 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4911 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4912 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4913</pre>
4914
4915<h5>Overview:</h5>
4916
4917<p>
4918The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4919specified (positive or negative) power.
4920</p>
4921
4922<h5>Arguments:</h5>
4923
4924<p>
4925The second argument is a floating point power, and the first is a value to
4926raise to that power.
4927</p>
4928
4929<h5>Semantics:</h5>
4930
4931<p>
4932This function returns the first value raised to the second power,
4933returning the
4934same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4935conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4936</div>
4937
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4938
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4939<!-- ======================================================================= -->
4940<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4941 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4942</div>
4943
4944<div class="doc_text">
4945<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4946LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4947These allow efficient code generation for some algorithms.
4948</p>
4949
4950</div>
4951
4952<!-- _______________________________________________________________________ -->
4953<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4954 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4955</div>
4956
4957<div class="doc_text">
4958
4959<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4960<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4961type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4962<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4963 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4964 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4965 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4966</pre>
4967
4968<h5>Overview:</h5>
4969
4970<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4971The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4972values with an even number of bytes (positive multiple of 16 bits). These are
4973useful for performing operations on data that is not in the target's native
4974byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4975</p>
4976
4977<h5>Semantics:</h5>
4978
4979<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4980The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4981and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4982intrinsic returns an i32 value that has the four bytes of the input i32
4983swapped, 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]4984i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4985<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4986additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4987</p>
4988
4989</div>
4990
4991<!-- _______________________________________________________________________ -->
4992<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4993 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4994</div>
4995
4996<div class="doc_text">
4997
4998<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4999<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
5000width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5001<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5002 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5003 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5004 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5005 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5006 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5007</pre>
5008
5009<h5>Overview:</h5>
5010
5011<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]5012The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5013value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5014</p>
5015
5016<h5>Arguments:</h5>
5017
5018<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5019The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5020integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5021</p>
5022
5023<h5>Semantics:</h5>
5024
5025<p>
5026The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5027</p>
5028</div>
5029
5030<!-- _______________________________________________________________________ -->
5031<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5032 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5033</div>
5034
5035<div class="doc_text">
5036
5037<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5038<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5039integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5040<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5041 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5042 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5043 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5044 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5045 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5046</pre>
5047
5048<h5>Overview:</h5>
5049
5050<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5051The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5052leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5053</p>
5054
5055<h5>Arguments:</h5>
5056
5057<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]5058The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5059integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5060</p>
5061
5062<h5>Semantics:</h5>
5063
5064<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5065The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5066in 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]5067of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]5068</p>
5069</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]5070
5071
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5072
5073<!-- _______________________________________________________________________ -->
5074<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5075 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5076</div>
5077
5078<div class="doc_text">
5079
5080<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5081<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5082integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5083<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5084 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5085 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5086 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5087 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5088 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5089</pre>
5090
5091<h5>Overview:</h5>
5092
5093<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5094The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5095trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5096</p>
5097
5098<h5>Arguments:</h5>
5099
5100<p>
5101The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5102integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5103</p>
5104
5105<h5>Semantics:</h5>
5106
5107<p>
5108The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5109in a variable. If the src == 0 then the result is the size in bits of the type
5110of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5111</p>
5112</div>
5113
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5114<!-- _______________________________________________________________________ -->
5115<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5116 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5117</div>
5118
5119<div class="doc_text">
5120
5121<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5122<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5123on any integer bit width.
5124<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5125 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5126 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5127</pre>
5128
5129<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5130<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5131range of bits from an integer value and returns them in the same bit width as
5132the original value.</p>
5133
5134<h5>Arguments:</h5>
5135<p>The first argument, <tt>%val</tt> and the result may be integer types of
5136any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5137arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5138
5139<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5140<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5141of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5142<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5143operates in forward mode.</p>
5144<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5145right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5146only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5147<ol>
5148 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5149 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5150 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5151 to determine the number of bits to retain.</li>
5152 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5153 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5154</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5155<p>In reverse mode, a similar computation is made except that the bits are
5156returned in the reverse order. So, for example, if <tt>X</tt> has the value
5157<tt>i16 0x0ACF (101011001111)</tt> and we apply
5158<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5159<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5160</div>
5161
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5162<div class="doc_subsubsection">
5163 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5164</div>
5165
5166<div class="doc_text">
5167
5168<h5>Syntax:</h5>
5169<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5170on any integer bit width.
5171<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5172 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5173 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]5174</pre>
5175
5176<h5>Overview:</h5>
5177<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5178of bits in an integer value with another integer value. It returns the integer
5179with the replaced bits.</p>
5180
5181<h5>Arguments:</h5>
5182<p>The first argument, <tt>%val</tt> and the result may be integer types of
5183any bit width but they must have the same bit width. <tt>%val</tt> is the value
5184whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5185integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5186type since they specify only a bit index.</p>
5187
5188<h5>Semantics:</h5>
5189<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5190of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5191<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5192operates in forward mode.</p>
5193<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5194truncating it down to the size of the replacement area or zero extending it
5195up to that size.</p>
5196<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5197are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5198in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5199to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5200<p>In reverse mode, a similar computation is made except that the bits are
5201reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5202<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]5203<h5>Examples:</h5>
5204<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5205 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5206 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5207 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5208 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5209 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5210</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5211</div>
5212
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5213<!-- ======================================================================= -->
5214<div class="doc_subsection">
5215 <a name="int_debugger">Debugger Intrinsics</a>
5216</div>
5217
5218<div class="doc_text">
5219<p>
5220The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5221are described in the <a
5222href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5223Debugging</a> document.
5224</p>
5225</div>
5226
5227
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5228<!-- ======================================================================= -->
5229<div class="doc_subsection">
5230 <a name="int_eh">Exception Handling Intrinsics</a>
5231</div>
5232
5233<div class="doc_text">
5234<p> The LLVM exception handling intrinsics (which all start with
5235<tt>llvm.eh.</tt> prefix), are described in the <a
5236href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5237Handling</a> document. </p>
5238</div>
5239
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5240<!-- ======================================================================= -->
5241<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5242 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5243</div>
5244
5245<div class="doc_text">
5246<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5247 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5248 the <tt>nest</tt> attribute, from a function. The result is a callable
5249 function pointer lacking the nest parameter - the caller does not need
5250 to provide a value for it. Instead, the value to use is stored in
5251 advance in a "trampoline", a block of memory usually allocated
5252 on the stack, which also contains code to splice the nest value into the
5253 argument list. This is used to implement the GCC nested function address
5254 extension.
5255</p>
5256<p>
5257 For example, if the function is
5258 <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]5259 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]5260<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5261 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5262 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5263 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5264 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5265</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5266 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5267 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5268</div>
5269
5270<!-- _______________________________________________________________________ -->
5271<div class="doc_subsubsection">
5272 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5273</div>
5274<div class="doc_text">
5275<h5>Syntax:</h5>
5276<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5277declare 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]5278</pre>
5279<h5>Overview:</h5>
5280<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5281 This fills the memory pointed to by <tt>tramp</tt> with code
5282 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5283</p>
5284<h5>Arguments:</h5>
5285<p>
5286 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5287 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5288 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5289 intrinsic. Note that the size and the alignment are target-specific - LLVM
5290 currently provides no portable way of determining them, so a front-end that
5291 generates this intrinsic needs to have some target-specific knowledge.
5292 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]5293</p>
5294<h5>Semantics:</h5>
5295<p>
5296 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5297 dependent code, turning it into a function. A pointer to this function is
5298 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5299 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5300 before being called. The new function's signature is the same as that of
5301 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5302 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5303 of pointer type. Calling the new function is equivalent to calling
5304 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5305 missing <tt>nest</tt> argument. If, after calling
5306 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5307 modified, then the effect of any later call to the returned function pointer is
5308 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5309</p>
5310</div>
5311
5312<!-- ======================================================================= -->
5313<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5314 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5315</div>
5316
5317<div class="doc_text">
5318<p>
5319 These intrinsic functions expand the "universal IR" of LLVM to represent
5320 hardware constructs for atomic operations and memory synchronization. This
5321 provides an interface to the hardware, not an interface to the programmer. It
5322 is aimed at a low enough level to allow any programming models or APIs which
5323 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5324 hardware behavior. Just as hardware provides a "universal IR" for source
5325 languages, it also provides a starting point for developing a "universal"
5326 atomic operation and synchronization IR.
5327</p>
5328<p>
5329 These do <em>not</em> form an API such as high-level threading libraries,
5330 software transaction memory systems, atomic primitives, and intrinsic
5331 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5332 application libraries. The hardware interface provided by LLVM should allow
5333 a clean implementation of all of these APIs and parallel programming models.
5334 No one model or paradigm should be selected above others unless the hardware
5335 itself ubiquitously does so.
5336
5337</p>
5338</div>
5339
5340<!-- _______________________________________________________________________ -->
5341<div class="doc_subsubsection">
5342 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5343</div>
5344<div class="doc_text">
5345<h5>Syntax:</h5>
5346<pre>
5347declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5348i1 &lt;device&gt; )
5349
5350</pre>
5351<h5>Overview:</h5>
5352<p>
5353 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5354 specific pairs of memory access types.
5355</p>
5356<h5>Arguments:</h5>
5357<p>
5358 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5359 The first four arguments enables a specific barrier as listed below. The fith
5360 argument specifies that the barrier applies to io or device or uncached memory.
5361
5362</p>
5363 <ul>
5364 <li><tt>ll</tt>: load-load barrier</li>
5365 <li><tt>ls</tt>: load-store barrier</li>
5366 <li><tt>sl</tt>: store-load barrier</li>
5367 <li><tt>ss</tt>: store-store barrier</li>
5368 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5369 </ul>
5370<h5>Semantics:</h5>
5371<p>
5372 This intrinsic causes the system to enforce some ordering constraints upon
5373 the loads and stores of the program. This barrier does not indicate
5374 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5375 which they occur. For any of the specified pairs of load and store operations
5376 (f.ex. load-load, or store-load), all of the first operations preceding the
5377 barrier will complete before any of the second operations succeeding the
5378 barrier begin. Specifically the semantics for each pairing is as follows:
5379</p>
5380 <ul>
5381 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5382 after the barrier begins.</li>
5383
5384 <li><tt>ls</tt>: All loads before the barrier must complete before any
5385 store after the barrier begins.</li>
5386 <li><tt>ss</tt>: All stores before the barrier must complete before any
5387 store after the barrier begins.</li>
5388 <li><tt>sl</tt>: All stores before the barrier must complete before any
5389 load after the barrier begins.</li>
5390 </ul>
5391<p>
5392 These semantics are applied with a logical "and" behavior when more than one
5393 is enabled in a single memory barrier intrinsic.
5394</p>
5395<p>
5396 Backends may implement stronger barriers than those requested when they do not
5397 support as fine grained a barrier as requested. Some architectures do not
5398 need all types of barriers and on such architectures, these become noops.
5399</p>
5400<h5>Example:</h5>
5401<pre>
5402%ptr = malloc i32
5403 store i32 4, %ptr
5404
5405%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5406 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5407 <i>; guarantee the above finishes</i>
5408 store i32 8, %ptr <i>; before this begins</i>
5409</pre>
5410</div>
5411
Andrew Lenharth95528942008-02-21 06:45:13 +0000[diff] [blame]5412<!-- _______________________________________________________________________ -->
5413<div class="doc_subsubsection">
5414 <a name="int_atomic_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
5415</div>
5416<div class="doc_text">
5417<h5>Syntax:</h5>
5418<p>
5419 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
5420 integer bit width. Not all targets support all bit widths however.</p>
5421
5422<pre>
5423declare i8 @llvm.atomic.lcs.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5424declare i16 @llvm.atomic.lcs.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5425declare i32 @llvm.atomic.lcs.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5426declare i64 @llvm.atomic.lcs.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
5427
5428</pre>
5429<h5>Overview:</h5>
5430<p>
5431 This loads a value in memory and compares it to a given value. If they are
5432 equal, it stores a new value into the memory.
5433</p>
5434<h5>Arguments:</h5>
5435<p>
5436 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
5437 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5438 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5439 this integer type. While any bit width integer may be used, targets may only
5440 lower representations they support in hardware.
5441
5442</p>
5443<h5>Semantics:</h5>
5444<p>
5445 This entire intrinsic must be executed atomically. It first loads the value
5446 in memory pointed to by <tt>ptr</tt> and compares it with the value
5447 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5448 loaded value is yielded in all cases. This provides the equivalent of an
5449 atomic compare-and-swap operation within the SSA framework.
5450</p>
5451<h5>Examples:</h5>
5452
5453<pre>
5454%ptr = malloc i32
5455 store i32 4, %ptr
5456
5457%val1 = add i32 4, 4
5458%result1 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 4, %val1 )
5459 <i>; yields {i32}:result1 = 4</i>
5460%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5461%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5462
5463%val2 = add i32 1, 1
5464%result2 = call i32 @llvm.atomic.lcs.i32( i32* %ptr, i32 5, %val2 )
5465 <i>; yields {i32}:result2 = 8</i>
5466%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5467
5468%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5469</pre>
5470</div>
5471
5472<!-- _______________________________________________________________________ -->
5473<div class="doc_subsubsection">
5474 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5475</div>
5476<div class="doc_text">
5477<h5>Syntax:</h5>
5478
5479<p>
5480 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5481 integer bit width. Not all targets support all bit widths however.</p>
5482<pre>
5483declare i8 @llvm.atomic.swap.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
5484declare i16 @llvm.atomic.swap.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
5485declare i32 @llvm.atomic.swap.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
5486declare i64 @llvm.atomic.swap.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
5487
5488</pre>
5489<h5>Overview:</h5>
5490<p>
5491 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
5492 the value from memory. It then stores the value in <tt>val</tt> in the memory
5493 at <tt>ptr</tt>.
5494</p>
5495<h5>Arguments:</h5>
5496
5497<p>
5498 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
5499 <tt>val</tt> argument and the result must be integers of the same bit width.
5500 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
5501 integer type. The targets may only lower integer representations they
5502 support.
5503</p>
5504<h5>Semantics:</h5>
5505<p>
5506 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
5507 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
5508 equivalent of an atomic swap operation within the SSA framework.
5509
5510</p>
5511<h5>Examples:</h5>
5512<pre>
5513%ptr = malloc i32
5514 store i32 4, %ptr
5515
5516%val1 = add i32 4, 4
5517%result1 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val1 )
5518 <i>; yields {i32}:result1 = 4</i>
5519%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5520%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5521
5522%val2 = add i32 1, 1
5523%result2 = call i32 @llvm.atomic.swap.i32( i32* %ptr, i32 %val2 )
5524 <i>; yields {i32}:result2 = 8</i>
5525
5526%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
5527%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
5528</pre>
5529</div>
5530
5531<!-- _______________________________________________________________________ -->
5532<div class="doc_subsubsection">
5533 <a name="int_atomic_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
5534
5535</div>
5536<div class="doc_text">
5537<h5>Syntax:</h5>
5538<p>
5539 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
5540 integer bit width. Not all targets support all bit widths however.</p>
5541<pre>
5542declare i8 @llvm.atomic.las.i8.( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5543declare i16 @llvm.atomic.las.i16.( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5544declare i32 @llvm.atomic.las.i32.( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5545declare i64 @llvm.atomic.las.i64.( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5546
5547</pre>
5548<h5>Overview:</h5>
5549<p>
5550 This intrinsic adds <tt>delta</tt> to the value stored in memory at
5551 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
5552</p>
5553<h5>Arguments:</h5>
5554<p>
5555
5556 The intrinsic takes two arguments, the first a pointer to an integer value
5557 and the second an integer value. The result is also an integer value. These
5558 integer types can have any bit width, but they must all have the same bit
5559 width. The targets may only lower integer representations they support.
5560</p>
5561<h5>Semantics:</h5>
5562<p>
5563 This intrinsic does a series of operations atomically. It first loads the
5564 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5565 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5566</p>
5567
5568<h5>Examples:</h5>
5569<pre>
5570%ptr = malloc i32
5571 store i32 4, %ptr
5572%result1 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 4 )
5573 <i>; yields {i32}:result1 = 4</i>
5574%result2 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 2 )
5575 <i>; yields {i32}:result2 = 8</i>
5576%result3 = call i32 @llvm.atomic.las.i32( i32* %ptr, i32 5 )
5577 <i>; yields {i32}:result3 = 10</i>
5578%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5579</pre>
5580</div>
5581
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]5582
5583<!-- ======================================================================= -->
5584<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5585 <a name="int_general">General Intrinsics</a>
5586</div>
5587
5588<div class="doc_text">
5589<p> This class of intrinsics is designed to be generic and has
5590no specific purpose. </p>
5591</div>
5592
5593<!-- _______________________________________________________________________ -->
5594<div class="doc_subsubsection">
5595 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5596</div>
5597
5598<div class="doc_text">
5599
5600<h5>Syntax:</h5>
5601<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5602 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]5603</pre>
5604
5605<h5>Overview:</h5>
5606
5607<p>
5608The '<tt>llvm.var.annotation</tt>' intrinsic
5609</p>
5610
5611<h5>Arguments:</h5>
5612
5613<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5614The first argument is a pointer to a value, the second is a pointer to a
5615global string, the third is a pointer to a global string which is the source
5616file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5617</p>
5618
5619<h5>Semantics:</h5>
5620
5621<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5622This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5623This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5624annotations. These have no other defined use, they are ignored by code
5625generation and optimization.
5626</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5627</div>
5628
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5629<!-- _______________________________________________________________________ -->
5630<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5631 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5632</div>
5633
5634<div class="doc_text">
5635
5636<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5637<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5638any integer bit width.
5639</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5640<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]5641 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5642 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5643 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5644 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5645 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]5646</pre>
5647
5648<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5649
5650<p>
5651The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5652</p>
5653
5654<h5>Arguments:</h5>
5655
5656<p>
5657The first argument is an integer value (result of some expression),
5658the second is a pointer to a global string, the third is a pointer to a global
5659string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5660It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5661</p>
5662
5663<h5>Semantics:</h5>
5664
5665<p>
5666This intrinsic allows annotations to be put on arbitrary expressions
5667with arbitrary strings. This can be useful for special purpose optimizations
5668that want to look for these annotations. These have no other defined use, they
5669are ignored by code generation and optimization.
5670</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5671
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5672<!-- _______________________________________________________________________ -->
5673<div class="doc_subsubsection">
5674 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5675</div>
5676
5677<div class="doc_text">
5678
5679<h5>Syntax:</h5>
5680<pre>
5681 declare void @llvm.trap()
5682</pre>
5683
5684<h5>Overview:</h5>
5685
5686<p>
5687The '<tt>llvm.trap</tt>' intrinsic
5688</p>
5689
5690<h5>Arguments:</h5>
5691
5692<p>
5693None
5694</p>
5695
5696<h5>Semantics:</h5>
5697
5698<p>
5699This intrinsics is lowered to the target dependent trap instruction. If the
5700target does not have a trap instruction, this intrinsic will be lowered to the
5701call of the abort() function.
5702</p>
5703</div>
5704
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5705<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5706<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5707<address>
5708 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5709 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5710 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]5711 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5712
5713 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]5714 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5715 Last modified: $Date$
5716</address>
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