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gerrit-public.fairphone.software / toolchain / llvm-project / 9b254eed320283371ee43f900e76794c3991957e / . / 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>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]147 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]149 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]150 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]151 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]152 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
154 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]155 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
156 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
157 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]158 </ol>
159 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]160 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
161 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]162 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
163 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
164 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]165 </ol>
166 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]167 <li><a href="#int_codegen">Code Generator Intrinsics</a>
168 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]169 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
170 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
171 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
172 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
173 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
174 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
175 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]176 </ol>
177 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]178 <li><a href="#int_libc">Standard C Library Intrinsics</a>
179 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]180 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
181 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
182 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
183 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
184 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]185 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
186 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
187 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]188 </ol>
189 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]190 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]191 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]192 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]193 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
194 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
195 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]196 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
197 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]198 </ol>
199 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]200 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]201 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]202 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]203 <ol>
204 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]205 </ol>
206 </li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame^]207 <li><a href="#int_atomics">Atomic intrinsics</a>
208 <ol>
209 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></li>
210 </ol>
211 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]212 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]213 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]214 <li><a href="#int_var_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]215 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]216 <li><a href="#int_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]217 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]218 <li><a href="#int_trap">
219 <tt>llvm.trap</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]220 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]221 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]222 </ol>
223 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]224</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]225
226<div class="doc_author">
227 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
228 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]229</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]230
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]231<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]232<div class="doc_section"> <a name="abstract">Abstract </a></div>
233<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]234
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]235<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]236<p>This document is a reference manual for the LLVM assembly language.
237LLVM is an SSA based representation that provides type safety,
238low-level operations, flexibility, and the capability of representing
239'all' high-level languages cleanly. It is the common code
240representation used throughout all phases of the LLVM compilation
241strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]242</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]243
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]244<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]245<div class="doc_section"> <a name="introduction">Introduction</a> </div>
246<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]247
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]248<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]249
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]250<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]251different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]252representation (suitable for fast loading by a Just-In-Time compiler),
253and as a human readable assembly language representation. This allows
254LLVM to provide a powerful intermediate representation for efficient
255compiler transformations and analysis, while providing a natural means
256to debug and visualize the transformations. The three different forms
257of LLVM are all equivalent. This document describes the human readable
258representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]259
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]260<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]261while being expressive, typed, and extensible at the same time. It
262aims to be a "universal IR" of sorts, by being at a low enough level
263that high-level ideas may be cleanly mapped to it (similar to how
264microprocessors are "universal IR's", allowing many source languages to
265be mapped to them). By providing type information, LLVM can be used as
266the target of optimizations: for example, through pointer analysis, it
267can be proven that a C automatic variable is never accessed outside of
268the current function... allowing it to be promoted to a simple SSA
269value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]271</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]272
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]273<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]274<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]275
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]276<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]277
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]278<p>It is important to note that this document describes 'well formed'
279LLVM assembly language. There is a difference between what the parser
280accepts and what is considered 'well formed'. For example, the
281following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]282
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]283<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]284<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]285%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]286</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]287</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]288
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]289<p>...because the definition of <tt>%x</tt> does not dominate all of
290its uses. The LLVM infrastructure provides a verification pass that may
291be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]292automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]293the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]294by the verifier pass indicate bugs in transformation passes or input to
295the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]296</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]297
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]298<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]299
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]300<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]301<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]302<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]303
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]304<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]305
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]306 <p>LLVM identifiers come in two basic types: global and local. Global
307 identifiers (functions, global variables) begin with the @ character. Local
308 identifiers (register names, types) begin with the % character. Additionally,
309 there are three different formats for identifiers, for different purposes:
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]310
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]311<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]312 <li>Named values are represented as a string of characters with their prefix.
313 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
314 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]315 Identifiers which require other characters in their names can be surrounded
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]316 with quotes. In this way, anything except a <tt>&quot;</tt> character can
317 be used in a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]318
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]319 <li>Unnamed values are represented as an unsigned numeric value with their
320 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]321
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]322 <li>Constants, which are described in a <a href="#constants">section about
323 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]324</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]325
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]326<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]327don't need to worry about name clashes with reserved words, and the set of
328reserved words may be expanded in the future without penalty. Additionally,
329unnamed identifiers allow a compiler to quickly come up with a temporary
330variable without having to avoid symbol table conflicts.</p>
331
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]332<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]333languages. There are keywords for different opcodes
334('<tt><a href="#i_add">add</a></tt>',
335 '<tt><a href="#i_bitcast">bitcast</a></tt>',
336 '<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]337href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]338and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]339none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]340
341<p>Here is an example of LLVM code to multiply the integer variable
342'<tt>%X</tt>' by 8:</p>
343
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]344<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]345
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]346<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]347<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]348%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]349</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]350</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]351
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]352<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]353
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]354<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]355<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]356%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]357</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]358</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]359
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]360<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]361
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]362<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]363<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]364<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
365<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
366%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]367</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]368</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]369
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]370<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
371important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]372
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]373<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]374
375 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
376 line.</li>
377
378 <li>Unnamed temporaries are created when the result of a computation is not
379 assigned to a named value.</li>
380
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]381 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]382
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]383</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]384
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]385<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]386demonstrating instructions, we will follow an instruction with a comment that
387defines the type and name of value produced. Comments are shown in italic
388text.</p>
389
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]390</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]391
392<!-- *********************************************************************** -->
393<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
394<!-- *********************************************************************** -->
395
396<!-- ======================================================================= -->
397<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
398</div>
399
400<div class="doc_text">
401
402<p>LLVM programs are composed of "Module"s, each of which is a
403translation unit of the input programs. Each module consists of
404functions, global variables, and symbol table entries. Modules may be
405combined together with the LLVM linker, which merges function (and
406global variable) definitions, resolves forward declarations, and merges
407symbol table entries. Here is an example of the "hello world" module:</p>
408
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]409<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]410<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]411<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
412 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]413
414<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]415<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]416
417<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]418define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]419 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]420 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]421 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]422
423 <i>; Call puts function to write out the string to stdout...</i>
424 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]425 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]426 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]427 href="#i_ret">ret</a> i32 0<br>}<br>
428</pre>
429</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]430
431<p>This example is made up of a <a href="#globalvars">global variable</a>
432named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
433function, and a <a href="#functionstructure">function definition</a>
434for "<tt>main</tt>".</p>
435
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]436<p>In general, a module is made up of a list of global values,
437where both functions and global variables are global values. Global values are
438represented by a pointer to a memory location (in this case, a pointer to an
439array of char, and a pointer to a function), and have one of the following <a
440href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]441
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442</div>
443
444<!-- ======================================================================= -->
445<div class="doc_subsection">
446 <a name="linkage">Linkage Types</a>
447</div>
448
449<div class="doc_text">
450
451<p>
452All Global Variables and Functions have one of the following types of linkage:
453</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]454
455<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]456
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]457 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]458
459 <dd>Global values with internal linkage are only directly accessible by
460 objects in the current module. In particular, linking code into a module with
461 an internal global value may cause the internal to be renamed as necessary to
462 avoid collisions. Because the symbol is internal to the module, all
463 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]464 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]465 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]467 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]469 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
470 the same name when linkage occurs. This is typically used to implement
471 inline functions, templates, or other code which must be generated in each
472 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
473 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]474 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]475
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]476 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]477
478 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
479 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]480 used for globals that may be emitted in multiple translation units, but that
481 are not guaranteed to be emitted into every translation unit that uses them.
482 One example of this are common globals in C, such as "<tt>int X;</tt>" at
483 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]484 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]485
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]486 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]487
488 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
489 pointer to array type. When two global variables with appending linkage are
490 linked together, the two global arrays are appended together. This is the
491 LLVM, typesafe, equivalent of having the system linker append together
492 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]494
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]495 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
496 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
497 until linked, if not linked, the symbol becomes null instead of being an
498 undefined reference.
499 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]500
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]501 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]502
503 <dd>If none of the above identifiers are used, the global is externally
504 visible, meaning that it participates in linkage and can be used to resolve
505 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]506 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]507</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]508
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]509 <p>
510 The next two types of linkage are targeted for Microsoft Windows platform
511 only. They are designed to support importing (exporting) symbols from (to)
512 DLLs.
513 </p>
514
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]515 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]516 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
517
518 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
519 or variable via a global pointer to a pointer that is set up by the DLL
520 exporting the symbol. On Microsoft Windows targets, the pointer name is
521 formed by combining <code>_imp__</code> and the function or variable name.
522 </dd>
523
524 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
525
526 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
527 pointer to a pointer in a DLL, so that it can be referenced with the
528 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
529 name is formed by combining <code>_imp__</code> and the function or variable
530 name.
531 </dd>
532
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]533</dl>
534
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]535<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]536variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
537variable and was linked with this one, one of the two would be renamed,
538preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
539external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]540outside of the current module.</p>
541<p>It is illegal for a function <i>declaration</i>
542to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]543or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]544<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
545linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]546</div>
547
548<!-- ======================================================================= -->
549<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]550 <a name="callingconv">Calling Conventions</a>
551</div>
552
553<div class="doc_text">
554
555<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
556and <a href="#i_invoke">invokes</a> can all have an optional calling convention
557specified for the call. The calling convention of any pair of dynamic
558caller/callee must match, or the behavior of the program is undefined. The
559following calling conventions are supported by LLVM, and more may be added in
560the future:</p>
561
562<dl>
563 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
564
565 <dd>This calling convention (the default if no other calling convention is
566 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]567 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]568 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]569 </dd>
570
571 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
572
573 <dd>This calling convention attempts to make calls as fast as possible
574 (e.g. by passing things in registers). This calling convention allows the
575 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]576 without having to conform to an externally specified ABI. Implementations of
577 this convention should allow arbitrary tail call optimization to be supported.
578 This calling convention does not support varargs and requires the prototype of
579 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]580 </dd>
581
582 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
583
584 <dd>This calling convention attempts to make code in the caller as efficient
585 as possible under the assumption that the call is not commonly executed. As
586 such, these calls often preserve all registers so that the call does not break
587 any live ranges in the caller side. This calling convention does not support
588 varargs and requires the prototype of all callees to exactly match the
589 prototype of the function definition.
590 </dd>
591
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]592 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]593
594 <dd>Any calling convention may be specified by number, allowing
595 target-specific calling conventions to be used. Target specific calling
596 conventions start at 64.
597 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]598</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]599
600<p>More calling conventions can be added/defined on an as-needed basis, to
601support pascal conventions or any other well-known target-independent
602convention.</p>
603
604</div>
605
606<!-- ======================================================================= -->
607<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]608 <a name="visibility">Visibility Styles</a>
609</div>
610
611<div class="doc_text">
612
613<p>
614All Global Variables and Functions have one of the following visibility styles:
615</p>
616
617<dl>
618 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
619
620 <dd>On ELF, default visibility means that the declaration is visible to other
621 modules and, in shared libraries, means that the declared entity may be
622 overridden. On Darwin, default visibility means that the declaration is
623 visible to other modules. Default visibility corresponds to "external
624 linkage" in the language.
625 </dd>
626
627 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
628
629 <dd>Two declarations of an object with hidden visibility refer to the same
630 object if they are in the same shared object. Usually, hidden visibility
631 indicates that the symbol will not be placed into the dynamic symbol table,
632 so no other module (executable or shared library) can reference it
633 directly.
634 </dd>
635
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]636 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
637
638 <dd>On ELF, protected visibility indicates that the symbol will be placed in
639 the dynamic symbol table, but that references within the defining module will
640 bind to the local symbol. That is, the symbol cannot be overridden by another
641 module.
642 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]643</dl>
644
645</div>
646
647<!-- ======================================================================= -->
648<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]649 <a name="globalvars">Global Variables</a>
650</div>
651
652<div class="doc_text">
653
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]654<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]655instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]656an explicit section to be placed in, and may have an optional explicit alignment
657specified. A variable may be defined as "thread_local", which means that it
658will not be shared by threads (each thread will have a separated copy of the
659variable). A variable may be defined as a global "constant," which indicates
660that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]661optimization, allowing the global data to be placed in the read-only section of
662an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]663cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]664
665<p>
666LLVM explicitly allows <em>declarations</em> of global variables to be marked
667constant, even if the final definition of the global is not. This capability
668can be used to enable slightly better optimization of the program, but requires
669the language definition to guarantee that optimizations based on the
670'constantness' are valid for the translation units that do not include the
671definition.
672</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]673
674<p>As SSA values, global variables define pointer values that are in
675scope (i.e. they dominate) all basic blocks in the program. Global
676variables always define a pointer to their "content" type because they
677describe a region of memory, and all memory objects in LLVM are
678accessed through pointers.</p>
679
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]680<p>A global variable may be declared to reside in a target-specifc numbered
681address space. For targets that support them, address spaces may affect how
682optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000[diff] [blame]683the variable. The default address space is zero. The address space qualifier
684must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]685
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]686<p>LLVM allows an explicit section to be specified for globals. If the target
687supports it, it will emit globals to the section specified.</p>
688
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]689<p>An explicit alignment may be specified for a global. If not present, or if
690the alignment is set to zero, the alignment of the global is set by the target
691to whatever it feels convenient. If an explicit alignment is specified, the
692global is forced to have at least that much alignment. All alignments must be
693a power of 2.</p>
694
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]695<p>For example, the following defines a global in a numbered address space with
696an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]697
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]698<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]699<pre>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]700@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]701</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]702</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]703
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]704</div>
705
706
707<!-- ======================================================================= -->
708<div class="doc_subsection">
709 <a name="functionstructure">Functions</a>
710</div>
711
712<div class="doc_text">
713
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]714<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
715an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]716<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]717<a href="#callingconv">calling convention</a>, a return type, an optional
718<a href="#paramattrs">parameter attribute</a> for the return type, a function
719name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]720<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]721optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]722opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]723
724LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
725optional <a href="#linkage">linkage type</a>, an optional
726<a href="#visibility">visibility style</a>, an optional
727<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]728<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]729name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]730<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]731
732<p>A function definition contains a list of basic blocks, forming the CFG for
733the function. Each basic block may optionally start with a label (giving the
734basic block a symbol table entry), contains a list of instructions, and ends
735with a <a href="#terminators">terminator</a> instruction (such as a branch or
736function return).</p>
737
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]738<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]739executed on entrance to the function, and it is not allowed to have predecessor
740basic blocks (i.e. there can not be any branches to the entry block of a
741function). Because the block can have no predecessors, it also cannot have any
742<a href="#i_phi">PHI nodes</a>.</p>
743
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]744<p>LLVM allows an explicit section to be specified for functions. If the target
745supports it, it will emit functions to the section specified.</p>
746
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]747<p>An explicit alignment may be specified for a function. If not present, or if
748the alignment is set to zero, the alignment of the function is set by the target
749to whatever it feels convenient. If an explicit alignment is specified, the
750function is forced to have at least that much alignment. All alignments must be
751a power of 2.</p>
752
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]753</div>
754
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]755
756<!-- ======================================================================= -->
757<div class="doc_subsection">
758 <a name="aliasstructure">Aliases</a>
759</div>
760<div class="doc_text">
761 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikovb18f8f82007-04-28 13:45:00 +0000[diff] [blame]762 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]763 optional <a href="#linkage">linkage type</a>, and an
764 optional <a href="#visibility">visibility style</a>.</p>
765
766 <h5>Syntax:</h5>
767
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]768<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]769<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]770@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]771</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]772</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]773
774</div>
775
776
777
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]778<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]779<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
780<div class="doc_text">
781 <p>The return type and each parameter of a function type may have a set of
782 <i>parameter attributes</i> associated with them. Parameter attributes are
783 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]784 a function. Parameter attributes are considered to be part of the function,
785 not of the function type, so functions with different parameter attributes
786 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]787
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]788 <p>Parameter attributes are simple keywords that follow the type specified. If
789 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]790 example:</p>
791
792<div class="doc_code">
793<pre>
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]794declare i32 @printf(i8* noalias , ...) nounwind
795declare i32 @atoi(i8*) nounwind readonly
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]796</pre>
797</div>
798
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]799 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
800 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]801
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]802 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]803 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]804 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]805 <dd>This indicates that the parameter should be zero extended just before
806 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]807
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]808 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]809 <dd>This indicates that the parameter should be sign extended just before
810 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]811
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]812 <dt><tt>inreg</tt></dt>
813 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]814 possible) during assembling function call. Support for this attribute is
815 target-specific</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]816
817 <dt><tt>byval</tt></dt>
Chris Lattner352ab9b2008-01-15 04:34:22 +0000[diff] [blame]818 <dd>This indicates that the pointer parameter should really be passed by
819 value to the function. The attribute implies that a hidden copy of the
820 pointee is made between the caller and the callee, so the callee is unable
821 to modify the value in the callee. This attribute is only valid on llvm
822 pointer arguments. It is generally used to pass structs and arrays by
823 value, but is also valid on scalars (even though this is silly).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]824
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]825 <dt><tt>sret</tt></dt>
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]826 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]827 that is the return value of the function in the source program.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]828
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]829 <dt><tt>noalias</tt></dt>
830 <dd>This indicates that the parameter not alias any other object or any
831 other "noalias" objects during the function call.
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]832
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]833 <dt><tt>noreturn</tt></dt>
834 <dd>This function attribute indicates that the function never returns. This
835 indicates to LLVM that every call to this function should be treated as if
836 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]837
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]838 <dt><tt>nounwind</tt></dt>
839 <dd>This function attribute indicates that the function type does not use
840 the unwind instruction and does not allow stack unwinding to propagate
841 through it.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]842
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]843 <dt><tt>nest</tt></dt>
844 <dd>This indicates that the parameter can be excised using the
845 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]846 <dt><tt>readonly</tt></dt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]847 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]848 except for producing a return value or throwing an exception. The value
849 returned must only depend on the function arguments and/or global variables.
850 It may use values obtained by dereferencing pointers.</dd>
851 <dt><tt>readnone</tt></dt>
852 <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]853 function, but in addition it is not allowed to dereference any pointer arguments
854 or global variables.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]855 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]856
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]857</div>
858
859<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]860<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]861 <a name="gc">Garbage Collector Names</a>
862</div>
863
864<div class="doc_text">
865<p>Each function may specify a garbage collector name, which is simply a
866string.</p>
867
868<div class="doc_code"><pre
869>define void @f() gc "name" { ...</pre></div>
870
871<p>The compiler declares the supported values of <i>name</i>. Specifying a
872collector which will cause the compiler to alter its output in order to support
873the named garbage collection algorithm.</p>
874</div>
875
876<!-- ======================================================================= -->
877<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]878 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]879</div>
880
881<div class="doc_text">
882<p>
883Modules may contain "module-level inline asm" blocks, which corresponds to the
884GCC "file scope inline asm" blocks. These blocks are internally concatenated by
885LLVM and treated as a single unit, but may be separated in the .ll file if
886desired. The syntax is very simple:
887</p>
888
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]889<div class="doc_code">
890<pre>
891module asm "inline asm code goes here"
892module asm "more can go here"
893</pre>
894</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]895
896<p>The strings can contain any character by escaping non-printable characters.
897 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
898 for the number.
899</p>
900
901<p>
902 The inline asm code is simply printed to the machine code .s file when
903 assembly code is generated.
904</p>
905</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]906
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]907<!-- ======================================================================= -->
908<div class="doc_subsection">
909 <a name="datalayout">Data Layout</a>
910</div>
911
912<div class="doc_text">
913<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]914data is to be laid out in memory. The syntax for the data layout is simply:</p>
915<pre> target datalayout = "<i>layout specification</i>"</pre>
916<p>The <i>layout specification</i> consists of a list of specifications
917separated by the minus sign character ('-'). Each specification starts with a
918letter and may include other information after the letter to define some
919aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]920<dl>
921 <dt><tt>E</tt></dt>
922 <dd>Specifies that the target lays out data in big-endian form. That is, the
923 bits with the most significance have the lowest address location.</dd>
924 <dt><tt>e</tt></dt>
925 <dd>Specifies that hte target lays out data in little-endian form. That is,
926 the bits with the least significance have the lowest address location.</dd>
927 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
928 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
929 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
930 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
931 too.</dd>
932 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
933 <dd>This specifies the alignment for an integer type of a given bit
934 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
935 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
936 <dd>This specifies the alignment for a vector type of a given bit
937 <i>size</i>.</dd>
938 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
939 <dd>This specifies the alignment for a floating point type of a given bit
940 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
941 (double).</dd>
942 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
943 <dd>This specifies the alignment for an aggregate type of a given bit
944 <i>size</i>.</dd>
945</dl>
946<p>When constructing the data layout for a given target, LLVM starts with a
947default set of specifications which are then (possibly) overriden by the
948specifications in the <tt>datalayout</tt> keyword. The default specifications
949are given in this list:</p>
950<ul>
951 <li><tt>E</tt> - big endian</li>
952 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
953 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
954 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
955 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
956 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
957 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
958 alignment of 64-bits</li>
959 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
960 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
961 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
962 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
963 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
964</ul>
965<p>When llvm is determining the alignment for a given type, it uses the
966following rules:
967<ol>
968 <li>If the type sought is an exact match for one of the specifications, that
969 specification is used.</li>
970 <li>If no match is found, and the type sought is an integer type, then the
971 smallest integer type that is larger than the bitwidth of the sought type is
972 used. If none of the specifications are larger than the bitwidth then the the
973 largest integer type is used. For example, given the default specifications
974 above, the i7 type will use the alignment of i8 (next largest) while both
975 i65 and i256 will use the alignment of i64 (largest specified).</li>
976 <li>If no match is found, and the type sought is a vector type, then the
977 largest vector type that is smaller than the sought vector type will be used
978 as a fall back. This happens because <128 x double> can be implemented in
979 terms of 64 <2 x double>, for example.</li>
980</ol>
981</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]982
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]983<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]984<div class="doc_section"> <a name="typesystem">Type System</a> </div>
985<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]986
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]987<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]988
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]989<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]990intermediate representation. Being typed enables a number of
991optimizations to be performed on the IR directly, without having to do
992extra analyses on the side before the transformation. A strong type
993system makes it easier to read the generated code and enables novel
994analyses and transformations that are not feasible to perform on normal
995three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]996
997</div>
998
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]999<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1000<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1001Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1002<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1003<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1004classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1005
1006<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1007 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1008 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1009 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1010 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1011 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1012 </tr>
1013 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1014 <td><a href="#t_floating">floating point</a></td>
1015 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1016 </tr>
1017 <tr>
1018 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1019 <td><a href="#t_integer">integer</a>,
1020 <a href="#t_floating">floating point</a>,
1021 <a href="#t_pointer">pointer</a>,
1022 <a href="#t_vector">vector</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1023 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1024 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1025 <tr>
1026 <td><a href="#t_primitive">primitive</a></td>
1027 <td><a href="#t_label">label</a>,
1028 <a href="#t_void">void</a>,
1029 <a href="#t_integer">integer</a>,
1030 <a href="#t_floating">floating point</a>.</td>
1031 </tr>
1032 <tr>
1033 <td><a href="#t_derived">derived</a></td>
1034 <td><a href="#t_integer">integer</a>,
1035 <a href="#t_array">array</a>,
1036 <a href="#t_function">function</a>,
1037 <a href="#t_pointer">pointer</a>,
1038 <a href="#t_struct">structure</a>,
1039 <a href="#t_pstruct">packed structure</a>,
1040 <a href="#t_vector">vector</a>,
1041 <a href="#t_opaque">opaque</a>.
1042 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1043 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1044</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1045
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1046<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1047most important. Values of these types are the only ones which can be
1048produced by instructions, passed as arguments, or used as operands to
1049instructions. This means that all structures and arrays must be
1050manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1051</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1052
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1053<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1054<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1055
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1056<div class="doc_text">
1057<p>The primitive types are the fundamental building blocks of the LLVM
1058system.</p>
1059
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1060</div>
1061
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1062<!-- _______________________________________________________________________ -->
1063<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1064
1065<div class="doc_text">
1066 <table>
1067 <tbody>
1068 <tr><th>Type</th><th>Description</th></tr>
1069 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1070 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1071 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1072 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1073 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1074 </tbody>
1075 </table>
1076</div>
1077
1078<!-- _______________________________________________________________________ -->
1079<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1080
1081<div class="doc_text">
1082<h5>Overview:</h5>
1083<p>The void type does not represent any value and has no size.</p>
1084
1085<h5>Syntax:</h5>
1086
1087<pre>
1088 void
1089</pre>
1090</div>
1091
1092<!-- _______________________________________________________________________ -->
1093<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1094
1095<div class="doc_text">
1096<h5>Overview:</h5>
1097<p>The label type represents code labels.</p>
1098
1099<h5>Syntax:</h5>
1100
1101<pre>
1102 label
1103</pre>
1104</div>
1105
1106
1107<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1108<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1109
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1110<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1111
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1112<p>The real power in LLVM comes from the derived types in the system.
1113This is what allows a programmer to represent arrays, functions,
1114pointers, and other useful types. Note that these derived types may be
1115recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1116
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1117</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1118
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1119<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1120<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1121
1122<div class="doc_text">
1123
1124<h5>Overview:</h5>
1125<p>The integer type is a very simple derived type that simply specifies an
1126arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11272^23-1 (about 8 million) can be specified.</p>
1128
1129<h5>Syntax:</h5>
1130
1131<pre>
1132 iN
1133</pre>
1134
1135<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1136value.</p>
1137
1138<h5>Examples:</h5>
1139<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1140 <tbody>
1141 <tr>
1142 <td><tt>i1</tt></td>
1143 <td>a single-bit integer.</td>
1144 </tr><tr>
1145 <td><tt>i32</tt></td>
1146 <td>a 32-bit integer.</td>
1147 </tr><tr>
1148 <td><tt>i1942652</tt></td>
1149 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1150 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1151 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1152</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1153</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1154
1155<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1156<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1157
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1158<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1159
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1160<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1161
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1162<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1163sequentially in memory. The array type requires a size (number of
1164elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1165
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1166<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1167
1168<pre>
1169 [&lt;# elements&gt; x &lt;elementtype&gt;]
1170</pre>
1171
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1172<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1173be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1174
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1175<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1176<table class="layout">
1177 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1178 <td class="left"><tt>[40 x i32]</tt></td>
1179 <td class="left">Array of 40 32-bit integer values.</td>
1180 </tr>
1181 <tr class="layout">
1182 <td class="left"><tt>[41 x i32]</tt></td>
1183 <td class="left">Array of 41 32-bit integer values.</td>
1184 </tr>
1185 <tr class="layout">
1186 <td class="left"><tt>[4 x i8]</tt></td>
1187 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1188 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1189</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1190<p>Here are some examples of multidimensional arrays:</p>
1191<table class="layout">
1192 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1193 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1194 <td class="left">3x4 array of 32-bit integer values.</td>
1195 </tr>
1196 <tr class="layout">
1197 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1198 <td class="left">12x10 array of single precision floating point values.</td>
1199 </tr>
1200 <tr class="layout">
1201 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1202 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1203 </tr>
1204</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1205
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1206<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1207length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1208LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1209As a special case, however, zero length arrays are recognized to be variable
1210length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1211type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1212
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1213</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1214
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1215<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1216<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1217<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1218<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1219<p>The function type can be thought of as a function signature. It
1220consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1221Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1222(which are structures of pointers to functions), for indirect function
1223calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1224<p>
1225The return type of a function type cannot be an aggregate type.
1226</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1227<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1228<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1229<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]1230specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1231which indicates that the function takes a variable number of arguments.
1232Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1233 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1234<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1235<table class="layout">
1236 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1237 <td class="left"><tt>i32 (i32)</tt></td>
1238 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1239 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1240 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1241 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1242 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1243 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1244 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1245 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1246 <tt>float</tt>.
1247 </td>
1248 </tr><tr class="layout">
1249 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1250 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1251 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1252 which returns an integer. This is the signature for <tt>printf</tt> in
1253 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1254 </td>
1255 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1256</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1257
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1258</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1259<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1260<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1261<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1262<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1263<p>The structure type is used to represent a collection of data members
1264together in memory. The packing of the field types is defined to match
1265the ABI of the underlying processor. The elements of a structure may
1266be any type that has a size.</p>
1267<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1268and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1269field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1270instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1271<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1272<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1273<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1274<table class="layout">
1275 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1276 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1277 <td class="left">A triple of three <tt>i32</tt> values</td>
1278 </tr><tr class="layout">
1279 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1280 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1281 second element is a <a href="#t_pointer">pointer</a> to a
1282 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1283 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1284 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1285</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1286</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1287
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1288<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1289<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1290</div>
1291<div class="doc_text">
1292<h5>Overview:</h5>
1293<p>The packed structure type is used to represent a collection of data members
1294together in memory. There is no padding between fields. Further, the alignment
1295of a packed structure is 1 byte. The elements of a packed structure may
1296be any type that has a size.</p>
1297<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1298and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1299field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1300instruction.</p>
1301<h5>Syntax:</h5>
1302<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1303<h5>Examples:</h5>
1304<table class="layout">
1305 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1306 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1307 <td class="left">A triple of three <tt>i32</tt> values</td>
1308 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1309 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1310 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1311 second element is a <a href="#t_pointer">pointer</a> to a
1312 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1313 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1314 </tr>
1315</table>
1316</div>
1317
1318<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1319<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1320<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1321<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1322<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1323reference to another object, which must live in memory. Pointer types may have
1324an optional address space attribute defining the target-specific numbered
1325address space where the pointed-to object resides. The default address space is
1326zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1327<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1328<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1329<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1330<table class="layout">
1331 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1332 <td class="left"><tt>[4x i32]*</tt></td>
1333 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1334 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1335 </tr>
1336 <tr class="layout">
1337 <td class="left"><tt>i32 (i32 *) *</tt></td>
1338 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1339 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1340 <tt>i32</tt>.</td>
1341 </tr>
1342 <tr class="layout">
1343 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1344 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1345 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1346 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1347</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1348</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1349
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1350<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1351<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1352<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1353
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1354<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1355
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1356<p>A vector type is a simple derived type that represents a vector
1357of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1358are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1359A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1360elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1361of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1362considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1363
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1364<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1365
1366<pre>
1367 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1368</pre>
1369
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1370<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1371be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1372
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1373<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1374
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1375<table class="layout">
1376 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1377 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1378 <td class="left">Vector of 4 32-bit integer values.</td>
1379 </tr>
1380 <tr class="layout">
1381 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1382 <td class="left">Vector of 8 32-bit floating-point values.</td>
1383 </tr>
1384 <tr class="layout">
1385 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1386 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1387 </tr>
1388</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1389</div>
1390
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1391<!-- _______________________________________________________________________ -->
1392<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1393<div class="doc_text">
1394
1395<h5>Overview:</h5>
1396
1397<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1398corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1399In LLVM, opaque types can eventually be resolved to any type (not just a
1400structure type).</p>
1401
1402<h5>Syntax:</h5>
1403
1404<pre>
1405 opaque
1406</pre>
1407
1408<h5>Examples:</h5>
1409
1410<table class="layout">
1411 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1412 <td class="left"><tt>opaque</tt></td>
1413 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1414 </tr>
1415</table>
1416</div>
1417
1418
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1419<!-- *********************************************************************** -->
1420<div class="doc_section"> <a name="constants">Constants</a> </div>
1421<!-- *********************************************************************** -->
1422
1423<div class="doc_text">
1424
1425<p>LLVM has several different basic types of constants. This section describes
1426them all and their syntax.</p>
1427
1428</div>
1429
1430<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1431<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1432
1433<div class="doc_text">
1434
1435<dl>
1436 <dt><b>Boolean constants</b></dt>
1437
1438 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1439 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1440 </dd>
1441
1442 <dt><b>Integer constants</b></dt>
1443
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1444 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1445 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1446 integer types.
1447 </dd>
1448
1449 <dt><b>Floating point constants</b></dt>
1450
1451 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1452 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1453 notation (see below). Floating point constants must have a <a
1454 href="#t_floating">floating point</a> type. </dd>
1455
1456 <dt><b>Null pointer constants</b></dt>
1457
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1458 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1459 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1460
1461</dl>
1462
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1463<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1464of floating point constants. For example, the form '<tt>double
14650x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14664.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1467(and the only time that they are generated by the disassembler) is when a
1468floating point constant must be emitted but it cannot be represented as a
1469decimal floating point number. For example, NaN's, infinities, and other
1470special values are represented in their IEEE hexadecimal format so that
1471assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1472
1473</div>
1474
1475<!-- ======================================================================= -->
1476<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1477</div>
1478
1479<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1480<p>Aggregate constants arise from aggregation of simple constants
1481and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1482
1483<dl>
1484 <dt><b>Structure constants</b></dt>
1485
1486 <dd>Structure constants are represented with notation similar to structure
1487 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1488 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1489 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]1490 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1491 types of elements must match those specified by the type.
1492 </dd>
1493
1494 <dt><b>Array constants</b></dt>
1495
1496 <dd>Array constants are represented with notation similar to array type
1497 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1498 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1499 constants must have <a href="#t_array">array type</a>, and the number and
1500 types of elements must match those specified by the type.
1501 </dd>
1502
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1503 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1504
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1505 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1506 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1507 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]1508 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1509 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1510 match those specified by the type.
1511 </dd>
1512
1513 <dt><b>Zero initialization</b></dt>
1514
1515 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1516 value to zero of <em>any</em> type, including scalar and aggregate types.
1517 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]1518 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1519 initializers.
1520 </dd>
1521</dl>
1522
1523</div>
1524
1525<!-- ======================================================================= -->
1526<div class="doc_subsection">
1527 <a name="globalconstants">Global Variable and Function Addresses</a>
1528</div>
1529
1530<div class="doc_text">
1531
1532<p>The addresses of <a href="#globalvars">global variables</a> and <a
1533href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1534constants. These constants are explicitly referenced when the <a
1535href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1536href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1537file:</p>
1538
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1539<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1540<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1541@X = global i32 17
1542@Y = global i32 42
1543@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1544</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1545</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1546
1547</div>
1548
1549<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1550<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1551<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1552 <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]1553 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1554 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1555
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1556 <p>Undefined values indicate to the compiler that the program is well defined
1557 no matter what value is used, giving the compiler more freedom to optimize.
1558 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1559</div>
1560
1561<!-- ======================================================================= -->
1562<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1563</div>
1564
1565<div class="doc_text">
1566
1567<p>Constant expressions are used to allow expressions involving other constants
1568to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1569href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1570that does not have side effects (e.g. load and call are not supported). The
1571following is the syntax for constant expressions:</p>
1572
1573<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1574 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1575 <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]1576 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1577
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1578 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1579 <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]1580 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]1581
1582 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1583 <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]1584 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]1585
1586 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1587 <dd>Truncate a floating point constant to another floating point type. The
1588 size of CST must be larger than the size of TYPE. Both types must be
1589 floating point.</dd>
1590
1591 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1592 <dd>Floating point extend a constant to another type. The size of CST must be
1593 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1594
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1595 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1596 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1597 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1598 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1599 of the same number of elements. If the value won't fit in the integer type,
1600 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1601
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1602 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1603 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1604 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1605 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1606 of the same number of elements. If the value won't fit in the integer type,
1607 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1608
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1609 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1610 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1611 constant. TYPE must be a scalar or vector floating point type. CST must be of
1612 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1613 of the same number of elements. If the value won't fit in the floating point
1614 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1615
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1616 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1617 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1618 constant. TYPE must be a scalar or vector floating point type. CST must be of
1619 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1620 of the same number of elements. If the value won't fit in the floating point
1621 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1622
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1623 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1624 <dd>Convert a pointer typed constant to the corresponding integer constant
1625 TYPE must be an integer type. CST must be of pointer type. The CST value is
1626 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1627
1628 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1629 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1630 pointer type. CST must be of integer type. The CST value is zero extended,
1631 truncated, or unchanged to make it fit in a pointer size. This one is
1632 <i>really</i> dangerous!</dd>
1633
1634 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1635 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1636 identical (same number of bits). The conversion is done as if the CST value
1637 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]1638 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1639 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]1640 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1641 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1642
1643 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1644
1645 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1646 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1647 instruction, the index list may have zero or more indexes, which are required
1648 to make sense for the type of "CSTPTR".</dd>
1649
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1650 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1651
1652 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1653 constants.</dd>
1654
1655 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1656 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1657
1658 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1659 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1660
1661 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1662
1663 <dd>Perform the <a href="#i_extractelement">extractelement
1664 operation</a> on constants.
1665
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1666 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1667
1668 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1669 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1670
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1671
1672 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1673
1674 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1675 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1676
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1677 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1678
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1679 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1680 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1681 binary</a> operations. The constraints on operands are the same as those for
1682 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1683 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1684</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1685</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1686
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1687<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1688<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1689<!-- *********************************************************************** -->
1690
1691<!-- ======================================================================= -->
1692<div class="doc_subsection">
1693<a name="inlineasm">Inline Assembler Expressions</a>
1694</div>
1695
1696<div class="doc_text">
1697
1698<p>
1699LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1700Module-Level Inline Assembly</a>) through the use of a special value. This
1701value represents the inline assembler as a string (containing the instructions
1702to emit), a list of operand constraints (stored as a string), and a flag that
1703indicates whether or not the inline asm expression has side effects. An example
1704inline assembler expression is:
1705</p>
1706
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1707<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1708<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1709i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1710</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1711</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1712
1713<p>
1714Inline assembler expressions may <b>only</b> be used as the callee operand of
1715a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1716</p>
1717
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1718<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1719<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1720%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]1721</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1722</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1723
1724<p>
1725Inline asms with side effects not visible in the constraint list must be marked
1726as having side effects. This is done through the use of the
1727'<tt>sideeffect</tt>' keyword, like so:
1728</p>
1729
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1730<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1731<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1732call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1733</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1734</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1735
1736<p>TODO: The format of the asm and constraints string still need to be
1737documented here. Constraints on what can be done (e.g. duplication, moving, etc
1738need to be documented).
1739</p>
1740
1741</div>
1742
1743<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1744<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1745<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1746
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1747<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1748
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1749<p>The LLVM instruction set consists of several different
1750classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1751instructions</a>, <a href="#binaryops">binary instructions</a>,
1752<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1753 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1754instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1755
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1756</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1757
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1758<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1759<div class="doc_subsection"> <a name="terminators">Terminator
1760Instructions</a> </div>
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>As mentioned <a href="#functionstructure">previously</a>, every
1765basic block in a program ends with a "Terminator" instruction, which
1766indicates which block should be executed after the current block is
1767finished. These terminator instructions typically yield a '<tt>void</tt>'
1768value: they produce control flow, not values (the one exception being
1769the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1770<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1771 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1772instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1773the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1774 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1775 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1776
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1777</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1778
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1779<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1780<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1781Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1782<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1783<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1784<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]1785 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1786</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1787<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1788<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1789value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1790<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1791returns a value and then causes control flow, and one that just causes
1792control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1793<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1794<p>The '<tt>ret</tt>' instruction may return any '<a
1795 href="#t_firstclass">first class</a>' type. Notice that a function is
1796not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1797instruction inside of the function that returns a value that does not
1798match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1799<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1800<p>When the '<tt>ret</tt>' instruction is executed, control flow
1801returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1802 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1803the instruction after the call. If the caller was an "<a
1804 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1805at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1806returns a value, that value shall set the call or invoke instruction's
1807return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1808<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1809<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1810 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1811</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1812</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1813<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1814<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1815<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1816<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1817<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]1818</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1819<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1820<p>The '<tt>br</tt>' instruction is used to cause control flow to
1821transfer to a different basic block in the current function. There are
1822two forms of this instruction, corresponding to a conditional branch
1823and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1824<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1825<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1826single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1827unconditional form of the '<tt>br</tt>' instruction takes a single
1828'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1830<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1831argument is evaluated. If the value is <tt>true</tt>, control flows
1832to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1833control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1834<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1835<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]1836 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]1837</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1838<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1839<div class="doc_subsubsection">
1840 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1841</div>
1842
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1843<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1844<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1845
1846<pre>
1847 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1848</pre>
1849
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1850<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1851
1852<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1853several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1854instruction, allowing a branch to occur to one of many possible
1855destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1856
1857
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1858<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1859
1860<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1861comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1862an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1863table is not allowed to contain duplicate constant entries.</p>
1864
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1865<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1866
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1867<p>The <tt>switch</tt> instruction specifies a table of values and
1868destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1869table is searched for the given value. If the value is found, control flow is
1870transfered to the corresponding destination; otherwise, control flow is
1871transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1872
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1873<h5>Implementation:</h5>
1874
1875<p>Depending on properties of the target machine and the particular
1876<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1877ways. For example, it could be generated as a series of chained conditional
1878branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1879
1880<h5>Example:</h5>
1881
1882<pre>
1883 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1884 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1885 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1886
1887 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1888 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1889
1890 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1891 switch i32 %val, label %otherwise [ i32 0, label %onzero
1892 i32 1, label %onone
1893 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1894</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1895</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1896
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1897<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1898<div class="doc_subsubsection">
1899 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1900</div>
1901
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1902<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1903
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1904<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1905
1906<pre>
1907 &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]1908 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1909</pre>
1910
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1911<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1912
1913<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1914function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1915'<tt>normal</tt>' label or the
1916'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1917"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1918"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1919href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1920continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1921
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1922<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1923
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1924<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1925
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1926<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1927 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1928 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1929 convention</a> the call should use. If none is specified, the call defaults
1930 to using C calling conventions.
1931 </li>
1932 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1933 function value being invoked. In most cases, this is a direct function
1934 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1935 an arbitrary pointer to function value.
1936 </li>
1937
1938 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1939 function to be invoked. </li>
1940
1941 <li>'<tt>function args</tt>': argument list whose types match the function
1942 signature argument types. If the function signature indicates the function
1943 accepts a variable number of arguments, the extra arguments can be
1944 specified. </li>
1945
1946 <li>'<tt>normal label</tt>': the label reached when the called function
1947 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1948
1949 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1950 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1951
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1952</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1953
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1954<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1955
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1956<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1957href="#i_call">call</a></tt>' instruction in most regards. The primary
1958difference is that it establishes an association with a label, which is used by
1959the runtime library to unwind the stack.</p>
1960
1961<p>This instruction is used in languages with destructors to ensure that proper
1962cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1963exception. Additionally, this is important for implementation of
1964'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1965
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1966<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1967<pre>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1968 %retval = invoke i32 %Test(i32 15) to label %Continue
1969 unwind label %TestCleanup <i>; {i32}:retval set</i>
1970 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1971 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1972</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1973</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1974
1975
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1976<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1977
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1978<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1979Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1980
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1981<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1982
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1983<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1984<pre>
1985 unwind
1986</pre>
1987
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1988<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1989
1990<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1991at the first callee in the dynamic call stack which used an <a
1992href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1993primarily used to implement exception handling.</p>
1994
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1995<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1996
1997<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1998immediately halt. The dynamic call stack is then searched for the first <a
1999href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2000execution continues at the "exceptional" destination block specified by the
2001<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2002dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2003</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]2004
2005<!-- _______________________________________________________________________ -->
2006
2007<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2008Instruction</a> </div>
2009
2010<div class="doc_text">
2011
2012<h5>Syntax:</h5>
2013<pre>
2014 unreachable
2015</pre>
2016
2017<h5>Overview:</h5>
2018
2019<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2020instruction is used to inform the optimizer that a particular portion of the
2021code is not reachable. This can be used to indicate that the code after a
2022no-return function cannot be reached, and other facts.</p>
2023
2024<h5>Semantics:</h5>
2025
2026<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2027</div>
2028
2029
2030
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2031<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2032<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2033<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2034<p>Binary operators are used to do most of the computation in a
2035program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2036produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2037multiple 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]2038The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2039necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2040<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2041</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2042<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2043<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2044Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2045<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2046<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2047<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]2048</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2049<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2050<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2051<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2052<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2053 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2054 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]2055Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2056<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2057<p>The value produced is the integer or floating point sum of the two
2058operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2059<p>If an integer sum has unsigned overflow, the result returned is the
2060mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2061the result.</p>
2062<p>Because LLVM integers use a two's complement representation, this
2063instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2064<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2065<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]2066</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2067</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2068<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2069<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2070Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2071<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2072<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2073<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]2074</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2076<p>The '<tt>sub</tt>' instruction returns the difference of its two
2077operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2078<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2079instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2080<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2081<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2082 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2083values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2084This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2085Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2086<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2087<p>The value produced is the integer or floating point difference of
2088the two operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2089<p>If an integer difference has unsigned overflow, the result returned is the
2090mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2091the result.</p>
2092<p>Because LLVM integers use a two's complement representation, this
2093instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2095<pre>
2096 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2097 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2098</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2099</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2100<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2101<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2102Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2103<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2104<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2105<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]2106</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2107<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2108<p>The '<tt>mul</tt>' instruction returns the product of its two
2109operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2110<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2111<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2112 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2113values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2114This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2115Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2116<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2117<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2118two operands.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2119<p>If the result of an integer multiplication has unsigned overflow,
2120the result returned is the mathematical result modulo
21212<sup>n</sup>, where n is the bit width of the result.</p>
2122<p>Because LLVM integers use a two's complement representation, and the
2123result is the same width as the operands, this instruction returns the
2124correct result for both signed and unsigned integers. If a full product
2125(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2126should be sign-extended or zero-extended as appropriate to the
2127width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2128<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2129<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]2130</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2131</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2132<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2133<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2134</a></div>
2135<div class="doc_text">
2136<h5>Syntax:</h5>
2137<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2138</pre>
2139<h5>Overview:</h5>
2140<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2141operands.</p>
2142<h5>Arguments:</h5>
2143<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2144<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2145types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2146of the values in which case the elements must be integers.</p>
2147<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2148<p>The value produced is the unsigned integer quotient of the two operands.</p>
2149<p>Note that unsigned integer division and signed integer division are distinct
2150operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2151<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2152<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2153<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]2154</pre>
2155</div>
2156<!-- _______________________________________________________________________ -->
2157<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2158</a> </div>
2159<div class="doc_text">
2160<h5>Syntax:</h5>
2161<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2162</pre>
2163<h5>Overview:</h5>
2164<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2165operands.</p>
2166<h5>Arguments:</h5>
2167<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2168<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2169types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2170of the values in which case the elements must be integers.</p>
2171<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2172<p>The value produced is the signed integer quotient of the two operands.</p>
2173<p>Note that signed integer division and unsigned integer division are distinct
2174operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2175<p>Division by zero leads to undefined behavior. Overflow also leads to
2176undefined behavior; this is a rare case, but can occur, for example,
2177by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2178<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2179<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]2180</pre>
2181</div>
2182<!-- _______________________________________________________________________ -->
2183<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2184Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2185<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2186<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2187<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]2188</pre>
2189<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2190<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2191operands.</p>
2192<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2193<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2194<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2195identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2196versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2197<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2198<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2199<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2200<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]2201</pre>
2202</div>
2203<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2204<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2205</div>
2206<div class="doc_text">
2207<h5>Syntax:</h5>
2208<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2209</pre>
2210<h5>Overview:</h5>
2211<p>The '<tt>urem</tt>' instruction returns the remainder from the
2212unsigned division of its two arguments.</p>
2213<h5>Arguments:</h5>
2214<p>The two arguments to the '<tt>urem</tt>' instruction must be
2215<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2216types. This instruction can also take <a href="#t_vector">vector</a> versions
2217of the values in which case the elements must be integers.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2218<h5>Semantics:</h5>
2219<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2220This instruction always performs an unsigned division to get the remainder,
2221regardless of whether the arguments are unsigned or not.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2222<p>Note that unsigned integer remainder and signed integer remainder are
2223distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2224<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2225<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2226<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]2227</pre>
2228
2229</div>
2230<!-- _______________________________________________________________________ -->
2231<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2232Instruction</a> </div>
2233<div class="doc_text">
2234<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2235<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]2236</pre>
2237<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2238<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2239signed division of its two operands. This instruction can also take
2240<a href="#t_vector">vector</a> versions of the values in which case
2241the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2242
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2243<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2244<p>The two arguments to the '<tt>srem</tt>' instruction must be
2245<a href="#t_integer">integer</a> values. Both arguments must have identical
2246types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2247<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2248<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2249has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2250operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2251a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2252 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2253Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2254please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2255Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]2256<p>Note that signed integer remainder and unsigned integer remainder are
2257distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2258<p>Taking the remainder of a division by zero leads to undefined behavior.
2259Overflow also leads to undefined behavior; this is a rare case, but can occur,
2260for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2261(The remainder doesn't actually overflow, but this rule lets srem be
2262implemented using instructions that return both the result of the division
2263and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2264<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2265<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]2266</pre>
2267
2268</div>
2269<!-- _______________________________________________________________________ -->
2270<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2271Instruction</a> </div>
2272<div class="doc_text">
2273<h5>Syntax:</h5>
2274<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2275</pre>
2276<h5>Overview:</h5>
2277<p>The '<tt>frem</tt>' instruction returns the remainder from the
2278division of its two operands.</p>
2279<h5>Arguments:</h5>
2280<p>The two arguments to the '<tt>frem</tt>' instruction must be
2281<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2282identical types. This instruction can also take <a href="#t_vector">vector</a>
2283versions of floating point values.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2284<h5>Semantics:</h5>
2285<p>This instruction returns the <i>remainder</i> of a division.</p>
2286<h5>Example:</h5>
2287<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]2288</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2289</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2290
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2291<!-- ======================================================================= -->
2292<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2293Operations</a> </div>
2294<div class="doc_text">
2295<p>Bitwise binary operators are used to do various forms of
2296bit-twiddling in a program. They are generally very efficient
2297instructions and can commonly be strength reduced from other
2298instructions. They require two operands, execute an operation on them,
2299and produce a single value. The resulting value of the bitwise binary
2300operators is always the same type as its first operand.</p>
2301</div>
2302
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2303<!-- _______________________________________________________________________ -->
2304<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2305Instruction</a> </div>
2306<div class="doc_text">
2307<h5>Syntax:</h5>
2308<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2309</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2310
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2311<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2312
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2313<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2314the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2315
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2316<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2317
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2318<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2319 href="#t_integer">integer</a> type.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2320
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2321<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2322
2323<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2324<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2325of bits in <tt>var1</tt>, the result is undefined.</p>
2326
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2327<h5>Example:</h5><pre>
2328 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2329 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2330 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2331 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2332</pre>
2333</div>
2334<!-- _______________________________________________________________________ -->
2335<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2336Instruction</a> </div>
2337<div class="doc_text">
2338<h5>Syntax:</h5>
2339<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2340</pre>
2341
2342<h5>Overview:</h5>
2343<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2344operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2345
2346<h5>Arguments:</h5>
2347<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2348<a href="#t_integer">integer</a> type.</p>
2349
2350<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2351
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2352<p>This instruction always performs a logical shift right operation. The most
2353significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2354shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2355the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2356
2357<h5>Example:</h5>
2358<pre>
2359 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2360 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2361 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2362 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2363 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2364</pre>
2365</div>
2366
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2367<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2368<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2369Instruction</a> </div>
2370<div class="doc_text">
2371
2372<h5>Syntax:</h5>
2373<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2374</pre>
2375
2376<h5>Overview:</h5>
2377<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2378operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2379
2380<h5>Arguments:</h5>
2381<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2382<a href="#t_integer">integer</a> type.</p>
2383
2384<h5>Semantics:</h5>
2385<p>This instruction always performs an arithmetic shift right operation,
2386The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2387of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2388larger than the number of bits in <tt>var1</tt>, the result is undefined.
2389</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2390
2391<h5>Example:</h5>
2392<pre>
2393 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2394 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2395 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2396 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2397 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2398</pre>
2399</div>
2400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2401<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2402<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2403Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2404<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2405<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2406<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]2407</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2408<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2409<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2410its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2411<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2412<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2413 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2414identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2415<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2416<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2417<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2418<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2419<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2420 <tbody>
2421 <tr>
2422 <td>In0</td>
2423 <td>In1</td>
2424 <td>Out</td>
2425 </tr>
2426 <tr>
2427 <td>0</td>
2428 <td>0</td>
2429 <td>0</td>
2430 </tr>
2431 <tr>
2432 <td>0</td>
2433 <td>1</td>
2434 <td>0</td>
2435 </tr>
2436 <tr>
2437 <td>1</td>
2438 <td>0</td>
2439 <td>0</td>
2440 </tr>
2441 <tr>
2442 <td>1</td>
2443 <td>1</td>
2444 <td>1</td>
2445 </tr>
2446 </tbody>
2447</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2448</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2449<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2450<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2451 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2452 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2453</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2454</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2455<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2456<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2457<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2458<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2459<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]2460</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2461<h5>Overview:</h5>
2462<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2463or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2464<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2465<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2466 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2467identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2468<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2469<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2470<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2471<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2472<table border="1" cellspacing="0" cellpadding="4">
2473 <tbody>
2474 <tr>
2475 <td>In0</td>
2476 <td>In1</td>
2477 <td>Out</td>
2478 </tr>
2479 <tr>
2480 <td>0</td>
2481 <td>0</td>
2482 <td>0</td>
2483 </tr>
2484 <tr>
2485 <td>0</td>
2486 <td>1</td>
2487 <td>1</td>
2488 </tr>
2489 <tr>
2490 <td>1</td>
2491 <td>0</td>
2492 <td>1</td>
2493 </tr>
2494 <tr>
2495 <td>1</td>
2496 <td>1</td>
2497 <td>1</td>
2498 </tr>
2499 </tbody>
2500</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2501</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2502<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2503<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2504 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2505 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2506</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2507</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2508<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2509<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2510Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2511<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2512<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2513<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]2514</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2515<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2516<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2517or of its two operands. The <tt>xor</tt> is used to implement the
2518"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2519<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2520<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2521 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2522identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2523<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2524<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2525<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2526<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2527<table border="1" cellspacing="0" cellpadding="4">
2528 <tbody>
2529 <tr>
2530 <td>In0</td>
2531 <td>In1</td>
2532 <td>Out</td>
2533 </tr>
2534 <tr>
2535 <td>0</td>
2536 <td>0</td>
2537 <td>0</td>
2538 </tr>
2539 <tr>
2540 <td>0</td>
2541 <td>1</td>
2542 <td>1</td>
2543 </tr>
2544 <tr>
2545 <td>1</td>
2546 <td>0</td>
2547 <td>1</td>
2548 </tr>
2549 <tr>
2550 <td>1</td>
2551 <td>1</td>
2552 <td>0</td>
2553 </tr>
2554 </tbody>
2555</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2556</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2557<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2558<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2559<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2560 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2561 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2562 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2563</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2564</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2565
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2566<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2567<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2568 <a name="vectorops">Vector Operations</a>
2569</div>
2570
2571<div class="doc_text">
2572
2573<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2574target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2575vector-specific operations needed to process vectors effectively. While LLVM
2576does directly support these vector operations, many sophisticated algorithms
2577will want to use target-specific intrinsics to take full advantage of a specific
2578target.</p>
2579
2580</div>
2581
2582<!-- _______________________________________________________________________ -->
2583<div class="doc_subsubsection">
2584 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2585</div>
2586
2587<div class="doc_text">
2588
2589<h5>Syntax:</h5>
2590
2591<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2592 &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]2593</pre>
2594
2595<h5>Overview:</h5>
2596
2597<p>
2598The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2599element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2600</p>
2601
2602
2603<h5>Arguments:</h5>
2604
2605<p>
2606The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2607value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2608an index indicating the position from which to extract the element.
2609The index may be a variable.</p>
2610
2611<h5>Semantics:</h5>
2612
2613<p>
2614The result is a scalar of the same type as the element type of
2615<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2616<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2617results are undefined.
2618</p>
2619
2620<h5>Example:</h5>
2621
2622<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2623 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2624</pre>
2625</div>
2626
2627
2628<!-- _______________________________________________________________________ -->
2629<div class="doc_subsubsection">
2630 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2631</div>
2632
2633<div class="doc_text">
2634
2635<h5>Syntax:</h5>
2636
2637<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2638 &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]2639</pre>
2640
2641<h5>Overview:</h5>
2642
2643<p>
2644The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2645element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2646</p>
2647
2648
2649<h5>Arguments:</h5>
2650
2651<p>
2652The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2653value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2654scalar value whose type must equal the element type of the first
2655operand. The third operand is an index indicating the position at
2656which to insert the value. The index may be a variable.</p>
2657
2658<h5>Semantics:</h5>
2659
2660<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2661The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2662element values are those of <tt>val</tt> except at position
2663<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2664exceeds the length of <tt>val</tt>, the results are undefined.
2665</p>
2666
2667<h5>Example:</h5>
2668
2669<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2670 %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]2671</pre>
2672</div>
2673
2674<!-- _______________________________________________________________________ -->
2675<div class="doc_subsubsection">
2676 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2677</div>
2678
2679<div class="doc_text">
2680
2681<h5>Syntax:</h5>
2682
2683<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2684 &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]2685</pre>
2686
2687<h5>Overview:</h5>
2688
2689<p>
2690The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2691from two input vectors, returning a vector of the same type.
2692</p>
2693
2694<h5>Arguments:</h5>
2695
2696<p>
2697The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2698with types that match each other and types that match the result of the
2699instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2700of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2701</p>
2702
2703<p>
2704The shuffle mask operand is required to be a constant vector with either
2705constant integer or undef values.
2706</p>
2707
2708<h5>Semantics:</h5>
2709
2710<p>
2711The elements of the two input vectors are numbered from left to right across
2712both of the vectors. The shuffle mask operand specifies, for each element of
2713the result vector, which element of the two input registers the result element
2714gets. The element selector may be undef (meaning "don't care") and the second
2715operand may be undef if performing a shuffle from only one vector.
2716</p>
2717
2718<h5>Example:</h5>
2719
2720<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2721 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2722 &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]2723 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2724 &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]2725</pre>
2726</div>
2727
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2728
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2729<!-- ======================================================================= -->
2730<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2731 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2732</div>
2733
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2734<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2735
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2736<p>A key design point of an SSA-based representation is how it
2737represents memory. In LLVM, no memory locations are in SSA form, which
2738makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2739allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2740
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2741</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2742
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2743<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2744<div class="doc_subsubsection">
2745 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2746</div>
2747
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2748<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2750<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2751
2752<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2753 &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]2754</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2755
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2756<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2757
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2758<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2759heap and returns a pointer to it. The object is always allocated in the generic
2760address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2761
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2762<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2763
2764<p>The '<tt>malloc</tt>' instruction allocates
2765<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2766bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2767appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]2768number of elements allocated, otherwise "NumElements" is defaulted to be one.
2769If an alignment is specified, the value result of the allocation is guaranteed to
2770be aligned to at least that boundary. If not specified, or if zero, the target can
2771choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2772
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2773<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2774
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2775<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2776
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2777<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2778a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2779
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2780<h5>Example:</h5>
2781
2782<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2783 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2784
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2785 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2786 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2787 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2788 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2789 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2790</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2791</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2792
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2793<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2794<div class="doc_subsubsection">
2795 <a name="i_free">'<tt>free</tt>' Instruction</a>
2796</div>
2797
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2798<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2799
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2800<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2801
2802<pre>
2803 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2804</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2806<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2807
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2808<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2809memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2810
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2811<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2812
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2813<p>'<tt>value</tt>' shall be a pointer value that points to a value
2814that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2815instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2816
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2817<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2818
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2819<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2820after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2822<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2823
2824<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2825 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2826 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2827</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2828</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2829
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2830<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2831<div class="doc_subsubsection">
2832 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2833</div>
2834
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2835<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2836
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2837<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2838
2839<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2840 &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]2841</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2842
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2843<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2844
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2845<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2846currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2847returns to its caller. The object is always allocated in the generic address
2848space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2849
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2850<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2851
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2852<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2853bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +0000[diff] [blame]2854appropriate type to the program. If "NumElements" is specified, it is the
2855number of elements allocated, otherwise "NumElements" is defaulted to be one.
2856If an alignment is specified, the value result of the allocation is guaranteed
2857to be aligned to at least that boundary. If not specified, or if zero, the target
2858can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2859
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2860<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2861
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2862<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2863
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2864<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2865memory is automatically released when the function returns. The '<tt>alloca</tt>'
2866instruction is commonly used to represent automatic variables that must
2867have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2868 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]2869instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2870
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2871<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2872
2873<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2874 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2875 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2876 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2877 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2878</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2879</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2880
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2881<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2882<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2883Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2884<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2885<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2886<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]2887<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2888<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2889<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2890<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2891address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2892 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2893marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2894the number or order of execution of this <tt>load</tt> with other
2895volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2896instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2897<p>
2898The optional "align" argument specifies the alignment of the operation
2899(that is, the alignment of the memory address). A value of 0 or an
2900omitted "align" argument means that the operation has the preferential
2901alignment for the target. It is the responsibility of the code emitter
2902to ensure that the alignment information is correct. Overestimating
2903the alignment results in an undefined behavior. Underestimating the
2904alignment may produce less efficient code. An alignment of 1 is always
2905safe.
2906</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2907<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2908<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2909<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2910<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2911 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2912 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2913 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2914</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2915</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2916<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2917<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2918Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2919<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2920<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2921<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2922 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]2923</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2924<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2925<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2926<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2927<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2928to 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]2929operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2930operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2931optimizer is not allowed to modify the number or order of execution of
2932this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2933 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2934<p>
2935The optional "align" argument specifies the alignment of the operation
2936(that is, the alignment of the memory address). A value of 0 or an
2937omitted "align" argument means that the operation has the preferential
2938alignment for the target. It is the responsibility of the code emitter
2939to ensure that the alignment information is correct. Overestimating
2940the alignment results in an undefined behavior. Underestimating the
2941alignment may produce less efficient code. An alignment of 1 is always
2942safe.
2943</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2944<h5>Semantics:</h5>
2945<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2946at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2947<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2948<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]2949 store i32 3, i32* %ptr <i>; yields {void}</i>
2950 %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]2951</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2952</div>
2953
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2955<div class="doc_subsubsection">
2956 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2957</div>
2958
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2959<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2960<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2961<pre>
2962 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2963</pre>
2964
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2965<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2966
2967<p>
2968The '<tt>getelementptr</tt>' instruction is used to get the address of a
2969subelement of an aggregate data structure.</p>
2970
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2971<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2972
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2973<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2974elements of the aggregate object to index to. The actual types of the arguments
2975provided depend on the type of the first pointer argument. The
2976'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2977levels 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]2978structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2979into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2980be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2981
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2982<p>For example, let's consider a C code fragment and how it gets
2983compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2984
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2985<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2986<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2987struct RT {
2988 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2989 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2990 char C;
2991};
2992struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2993 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2994 double Y;
2995 struct RT Z;
2996};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2997
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2998int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2999 return &amp;s[1].Z.B[5][13];
3000}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3001</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3002</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3003
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3004<p>The LLVM code generated by the GCC frontend is:</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]3008%RT = type { i8 , [10 x [20 x i32]], i8 }
3009%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3010
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3011define i32* %foo(%ST* %s) {
3012entry:
3013 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3014 ret i32* %reg
3015}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3016</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3017</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3018
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3019<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3020
3021<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]3022on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]3023and <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]3024<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]3025to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]3026<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3027
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3028<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]3029type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3030}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3031the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3032i8 }</tt>' type, another structure. The third index indexes into the second
3033element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3034array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3035'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3036to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3037
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3038<p>Note that it is perfectly legal to index partially through a
3039structure, returning a pointer to an inner element. Because of this,
3040the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3041
3042<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3043 define i32* %foo(%ST* %s) {
3044 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3045 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3046 %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]3047 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3048 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3049 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3050 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3051</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3052
3053<p>Note that it is undefined to access an array out of bounds: array and
3054pointer indexes must always be within the defined bounds of the array type.
3055The one exception for this rules is zero length arrays. These arrays are
3056defined to be accessible as variable length arrays, which requires access
3057beyond the zero'th element.</p>
3058
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3059<p>The getelementptr instruction is often confusing. For some more insight
3060into how it works, see <a href="GetElementPtr.html">the getelementptr
3061FAQ</a>.</p>
3062
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3063<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3064
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3065<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3066 <i>; yields [12 x i8]*:aptr</i>
3067 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3068</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3069</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3070
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3071<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3072<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3073</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3074<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3075<p>The instructions in this category are the conversion instructions (casting)
3076which all take a single operand and a type. They perform various bit conversions
3077on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3078</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3079
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3080<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3081<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3082 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3083</div>
3084<div class="doc_text">
3085
3086<h5>Syntax:</h5>
3087<pre>
3088 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3089</pre>
3090
3091<h5>Overview:</h5>
3092<p>
3093The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3094</p>
3095
3096<h5>Arguments:</h5>
3097<p>
3098The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3099be 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]3100and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3101type. The bit size of <tt>value</tt> must be larger than the bit size of
3102<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3103
3104<h5>Semantics:</h5>
3105<p>
3106The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3107and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3108larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3109It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3110
3111<h5>Example:</h5>
3112<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3113 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3114 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3115 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3116</pre>
3117</div>
3118
3119<!-- _______________________________________________________________________ -->
3120<div class="doc_subsubsection">
3121 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3122</div>
3123<div class="doc_text">
3124
3125<h5>Syntax:</h5>
3126<pre>
3127 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3128</pre>
3129
3130<h5>Overview:</h5>
3131<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3132<tt>ty2</tt>.</p>
3133
3134
3135<h5>Arguments:</h5>
3136<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]3137<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3138also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3139<tt>value</tt> must be smaller than the bit size of the destination type,
3140<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3141
3142<h5>Semantics:</h5>
3143<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]3144bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3145
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3146<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]3147
3148<h5>Example:</h5>
3149<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3150 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3151 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3152</pre>
3153</div>
3154
3155<!-- _______________________________________________________________________ -->
3156<div class="doc_subsubsection">
3157 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3158</div>
3159<div class="doc_text">
3160
3161<h5>Syntax:</h5>
3162<pre>
3163 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3164</pre>
3165
3166<h5>Overview:</h5>
3167<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3168
3169<h5>Arguments:</h5>
3170<p>
3171The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3172<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3173also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3174<tt>value</tt> must be smaller than the bit size of the destination type,
3175<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3176
3177<h5>Semantics:</h5>
3178<p>
3179The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3180bit (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]3181the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3182
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3183<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]3184
3185<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3186<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3187 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3188 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3189</pre>
3190</div>
3191
3192<!-- _______________________________________________________________________ -->
3193<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3194 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3195</div>
3196
3197<div class="doc_text">
3198
3199<h5>Syntax:</h5>
3200
3201<pre>
3202 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3203</pre>
3204
3205<h5>Overview:</h5>
3206<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3207<tt>ty2</tt>.</p>
3208
3209
3210<h5>Arguments:</h5>
3211<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3212 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3213cast it to. The size of <tt>value</tt> must be larger than the size of
3214<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3215<i>no-op cast</i>.</p>
3216
3217<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3218<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3219<a href="#t_floating">floating point</a> type to a smaller
3220<a href="#t_floating">floating point</a> type. If the value cannot fit within
3221the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3222
3223<h5>Example:</h5>
3224<pre>
3225 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3226 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3227</pre>
3228</div>
3229
3230<!-- _______________________________________________________________________ -->
3231<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3232 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3233</div>
3234<div class="doc_text">
3235
3236<h5>Syntax:</h5>
3237<pre>
3238 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3239</pre>
3240
3241<h5>Overview:</h5>
3242<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3243floating point value.</p>
3244
3245<h5>Arguments:</h5>
3246<p>The '<tt>fpext</tt>' instruction takes a
3247<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3248and a <a href="#t_floating">floating point</a> type to cast it to. The source
3249type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3250
3251<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3252<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3253<a href="#t_floating">floating point</a> type to a larger
3254<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3255used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3256<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]3257
3258<h5>Example:</h5>
3259<pre>
3260 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3261 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3262</pre>
3263</div>
3264
3265<!-- _______________________________________________________________________ -->
3266<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3267 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3268</div>
3269<div class="doc_text">
3270
3271<h5>Syntax:</h5>
3272<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3273 &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]3274</pre>
3275
3276<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3277<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3278unsigned integer equivalent of type <tt>ty2</tt>.
3279</p>
3280
3281<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3282<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]3283scalar or vector <a href="#t_floating">floating point</a> value, and a type
3284to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3285type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3286vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3287
3288<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3289<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3290<a href="#t_floating">floating point</a> operand into the nearest (rounding
3291towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3292the results are undefined.</p>
3293
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3294<h5>Example:</h5>
3295<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3296 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3297 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3298 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3299</pre>
3300</div>
3301
3302<!-- _______________________________________________________________________ -->
3303<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3304 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3305</div>
3306<div class="doc_text">
3307
3308<h5>Syntax:</h5>
3309<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3310 &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]3311</pre>
3312
3313<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3314<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3315<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]3316</p>
3317
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3318<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3319<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]3320scalar or vector <a href="#t_floating">floating point</a> value, and a type
3321to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3322type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3323vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3324
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3325<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3326<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3327<a href="#t_floating">floating point</a> operand into the nearest (rounding
3328towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3329the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3330
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3331<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3332<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3333 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3334 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3335 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3336</pre>
3337</div>
3338
3339<!-- _______________________________________________________________________ -->
3340<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3341 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3342</div>
3343<div class="doc_text">
3344
3345<h5>Syntax:</h5>
3346<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3347 &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]3348</pre>
3349
3350<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3351<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3352integer and converts that value to the <tt>ty2</tt> type.</p>
3353
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3354<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3355<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3356scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3357to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3358type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3359floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3360
3361<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3362<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3363integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3364the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3365
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3366<h5>Example:</h5>
3367<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3368 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3369 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3370</pre>
3371</div>
3372
3373<!-- _______________________________________________________________________ -->
3374<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3375 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3376</div>
3377<div class="doc_text">
3378
3379<h5>Syntax:</h5>
3380<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3381 &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]3382</pre>
3383
3384<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3385<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3386integer and converts that value to the <tt>ty2</tt> type.</p>
3387
3388<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3389<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3390scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3391to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3392type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3393floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3394
3395<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3396<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3397integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3398the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3399
3400<h5>Example:</h5>
3401<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3402 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3403 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3404</pre>
3405</div>
3406
3407<!-- _______________________________________________________________________ -->
3408<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3409 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3410</div>
3411<div class="doc_text">
3412
3413<h5>Syntax:</h5>
3414<pre>
3415 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3416</pre>
3417
3418<h5>Overview:</h5>
3419<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3420the integer type <tt>ty2</tt>.</p>
3421
3422<h5>Arguments:</h5>
3423<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3424must 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]3425<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3426
3427<h5>Semantics:</h5>
3428<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3429<tt>ty2</tt> by interpreting the pointer value as an integer and either
3430truncating or zero extending that value to the size of the integer type. If
3431<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3432<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]3433are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3434change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3435
3436<h5>Example:</h5>
3437<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3438 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3439 %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]3440</pre>
3441</div>
3442
3443<!-- _______________________________________________________________________ -->
3444<div class="doc_subsubsection">
3445 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3446</div>
3447<div class="doc_text">
3448
3449<h5>Syntax:</h5>
3450<pre>
3451 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3452</pre>
3453
3454<h5>Overview:</h5>
3455<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3456a pointer type, <tt>ty2</tt>.</p>
3457
3458<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3459<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3460value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3461<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3462
3463<h5>Semantics:</h5>
3464<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3465<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3466the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3467size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3468the size of a pointer then a zero extension is done. If they are the same size,
3469nothing is done (<i>no-op cast</i>).</p>
3470
3471<h5>Example:</h5>
3472<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3473 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3474 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3475 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3476</pre>
3477</div>
3478
3479<!-- _______________________________________________________________________ -->
3480<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3481 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3482</div>
3483<div class="doc_text">
3484
3485<h5>Syntax:</h5>
3486<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3487 &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]3488</pre>
3489
3490<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3491<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3492<tt>ty2</tt> without changing any bits.</p>
3493
3494<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3495<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3496a first class value, and a type to cast it to, which must also be a <a
3497 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3498and the destination type, <tt>ty2</tt>, must be identical. If the source
3499type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3500
3501<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3502<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3503<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3504this conversion. The conversion is done as if the <tt>value</tt> had been
3505stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3506converted to other pointer types with this instruction. To convert pointers to
3507other types, use the <a href="#i_inttoptr">inttoptr</a> or
3508<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3509
3510<h5>Example:</h5>
3511<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3512 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3513 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3514 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3515</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3516</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3517
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3518<!-- ======================================================================= -->
3519<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3520<div class="doc_text">
3521<p>The instructions in this category are the "miscellaneous"
3522instructions, which defy better classification.</p>
3523</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3524
3525<!-- _______________________________________________________________________ -->
3526<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3527</div>
3528<div class="doc_text">
3529<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3530<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]3531</pre>
3532<h5>Overview:</h5>
3533<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3534of its two integer operands.</p>
3535<h5>Arguments:</h5>
3536<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3537the condition code indicating the kind of comparison to perform. It is not
3538a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3539<ol>
3540 <li><tt>eq</tt>: equal</li>
3541 <li><tt>ne</tt>: not equal </li>
3542 <li><tt>ugt</tt>: unsigned greater than</li>
3543 <li><tt>uge</tt>: unsigned greater or equal</li>
3544 <li><tt>ult</tt>: unsigned less than</li>
3545 <li><tt>ule</tt>: unsigned less or equal</li>
3546 <li><tt>sgt</tt>: signed greater than</li>
3547 <li><tt>sge</tt>: signed greater or equal</li>
3548 <li><tt>slt</tt>: signed less than</li>
3549 <li><tt>sle</tt>: signed less or equal</li>
3550</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3551<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3552<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3553<h5>Semantics:</h5>
3554<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3555the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3556yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3557<ol>
3558 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3559 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3560 </li>
3561 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3562 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3563 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3564 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3565 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3566 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3567 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3568 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3569 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3570 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3571 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3572 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3573 <li><tt>sge</tt>: interprets the operands as signed values and yields
3574 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3575 <li><tt>slt</tt>: interprets the operands as signed values and yields
3576 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3577 <li><tt>sle</tt>: interprets the operands as signed values and yields
3578 <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]3579</ol>
3580<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3581values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3582
3583<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3584<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3585 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3586 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3587 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3588 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3589 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3590</pre>
3591</div>
3592
3593<!-- _______________________________________________________________________ -->
3594<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3595</div>
3596<div class="doc_text">
3597<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3598<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]3599</pre>
3600<h5>Overview:</h5>
3601<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3602of its floating point operands.</p>
3603<h5>Arguments:</h5>
3604<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3605the condition code indicating the kind of comparison to perform. It is not
3606a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3607<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3608 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3609 <li><tt>oeq</tt>: ordered and equal</li>
3610 <li><tt>ogt</tt>: ordered and greater than </li>
3611 <li><tt>oge</tt>: ordered and greater than or equal</li>
3612 <li><tt>olt</tt>: ordered and less than </li>
3613 <li><tt>ole</tt>: ordered and less than or equal</li>
3614 <li><tt>one</tt>: ordered and not equal</li>
3615 <li><tt>ord</tt>: ordered (no nans)</li>
3616 <li><tt>ueq</tt>: unordered or equal</li>
3617 <li><tt>ugt</tt>: unordered or greater than </li>
3618 <li><tt>uge</tt>: unordered or greater than or equal</li>
3619 <li><tt>ult</tt>: unordered or less than </li>
3620 <li><tt>ule</tt>: unordered or less than or equal</li>
3621 <li><tt>une</tt>: unordered or not equal</li>
3622 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3623 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3624</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3625<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3626<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3627<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3628<a href="#t_floating">floating point</a> typed. They must have identical
3629types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3630<h5>Semantics:</h5>
3631<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3632the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3633yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3634<ol>
3635 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3636 <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]3637 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3638 <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]3639 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3640 <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]3641 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3642 <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]3643 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3644 <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]3645 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3646 <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]3647 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3648 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3649 <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]3650 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3651 <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]3652 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3653 <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]3654 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3655 <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]3656 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3657 <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]3658 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3659 <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]3660 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3661 <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]3662 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3663</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3664
3665<h5>Example:</h5>
3666<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3667 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3668 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3669 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3670</pre>
3671</div>
3672
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3673<!-- _______________________________________________________________________ -->
3674<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3675Instruction</a> </div>
3676<div class="doc_text">
3677<h5>Syntax:</h5>
3678<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3679<h5>Overview:</h5>
3680<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3681the SSA graph representing the function.</p>
3682<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3683<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3684field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3685as arguments, with one pair for each predecessor basic block of the
3686current block. Only values of <a href="#t_firstclass">first class</a>
3687type may be used as the value arguments to the PHI node. Only labels
3688may be used as the label arguments.</p>
3689<p>There must be no non-phi instructions between the start of a basic
3690block and the PHI instructions: i.e. PHI instructions must be first in
3691a basic block.</p>
3692<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3693<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3694specified by the pair corresponding to the predecessor basic block that executed
3695just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3696<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3697<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]3698</div>
3699
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3700<!-- _______________________________________________________________________ -->
3701<div class="doc_subsubsection">
3702 <a name="i_select">'<tt>select</tt>' Instruction</a>
3703</div>
3704
3705<div class="doc_text">
3706
3707<h5>Syntax:</h5>
3708
3709<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3710 &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]3711</pre>
3712
3713<h5>Overview:</h5>
3714
3715<p>
3716The '<tt>select</tt>' instruction is used to choose one value based on a
3717condition, without branching.
3718</p>
3719
3720
3721<h5>Arguments:</h5>
3722
3723<p>
3724The '<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.
3725</p>
3726
3727<h5>Semantics:</h5>
3728
3729<p>
3730If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3731value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3732</p>
3733
3734<h5>Example:</h5>
3735
3736<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3737 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3738</pre>
3739</div>
3740
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3741
3742<!-- _______________________________________________________________________ -->
3743<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3744 <a name="i_call">'<tt>call</tt>' Instruction</a>
3745</div>
3746
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3747<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3748
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3749<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3750<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3751 &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]3752</pre>
3753
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3754<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3755
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3756<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3757
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3758<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3759
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3760<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3761
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3762<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3763 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3764 <p>The optional "tail" marker indicates whether the callee function accesses
3765 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3766 function call is eligible for tail call optimization. Note that calls may
3767 be marked "tail" even if they do not occur before a <a
3768 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3769 </li>
3770 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3771 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3772 convention</a> the call should use. If none is specified, the call defaults
3773 to using C calling conventions.
3774 </li>
3775 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3776 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3777 the type of the return value. Functions that return no value are marked
3778 <tt><a href="#t_void">void</a></tt>.</p>
3779 </li>
3780 <li>
3781 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3782 value being invoked. The argument types must match the types implied by
3783 this signature. This type can be omitted if the function is not varargs
3784 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3785 </li>
3786 <li>
3787 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3788 be invoked. In most cases, this is a direct function invocation, but
3789 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3790 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3791 </li>
3792 <li>
3793 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3794 function signature argument types. All arguments must be of
3795 <a href="#t_firstclass">first class</a> type. If the function signature
3796 indicates the function accepts a variable number of arguments, the extra
3797 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3798 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3799</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3800
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3801<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3802
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3803<p>The '<tt>call</tt>' instruction is used to cause control flow to
3804transfer to a specified function, with its incoming arguments bound to
3805the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3806instruction in the called function, control flow continues with the
3807instruction after the function call, and the return value of the
3808function is bound to the result argument. This is a simpler case of
3809the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3810
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3811<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3812
3813<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3814 %retval = call i32 @test(i32 %argc)
3815 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3816 %X = tail call i32 @foo()
3817 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3818 %Z = call void %foo(i8 97 signext)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3819</pre>
3820
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3821</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3822
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3823<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3824<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3825 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3826</div>
3827
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3828<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3829
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3830<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3831
3832<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3833 &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]3834</pre>
3835
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3836<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3837
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3838<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3839the "variable argument" area of a function call. It is used to implement the
3840<tt>va_arg</tt> macro in C.</p>
3841
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3842<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3843
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3844<p>This instruction takes a <tt>va_list*</tt> value and the type of
3845the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3846increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3847actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3848
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3849<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3850
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3851<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3852type from the specified <tt>va_list</tt> and causes the
3853<tt>va_list</tt> to point to the next argument. For more information,
3854see the variable argument handling <a href="#int_varargs">Intrinsic
3855Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3856
3857<p>It is legal for this instruction to be called in a function which does not
3858take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3859function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3860
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3861<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3862href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3863argument.</p>
3864
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3865<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3866
3867<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3868
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3869</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3870
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3871<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3872<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3873<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3874
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3875<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3876
3877<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3878well known names and semantics and are required to follow certain restrictions.
3879Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3880language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]3881adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3882
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3883<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3884prefix is reserved in LLVM for intrinsic names; thus, function names may not
3885begin with this prefix. Intrinsic functions must always be external functions:
3886you cannot define the body of intrinsic functions. Intrinsic functions may
3887only be used in call or invoke instructions: it is illegal to take the address
3888of an intrinsic function. Additionally, because intrinsic functions are part
3889of the LLVM language, it is required if any are added that they be documented
3890here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3891
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3892<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3893a family of functions that perform the same operation but on different data
3894types. Because LLVM can represent over 8 million different integer types,
3895overloading is used commonly to allow an intrinsic function to operate on any
3896integer type. One or more of the argument types or the result type can be
3897overloaded to accept any integer type. Argument types may also be defined as
3898exactly matching a previous argument's type or the result type. This allows an
3899intrinsic function which accepts multiple arguments, but needs all of them to
3900be of the same type, to only be overloaded with respect to a single argument or
3901the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3902
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3903<p>Overloaded intrinsics will have the names of its overloaded argument types
3904encoded into its function name, each preceded by a period. Only those types
3905which are overloaded result in a name suffix. Arguments whose type is matched
3906against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3907take an integer of any width and returns an integer of exactly the same integer
3908width. This leads to a family of functions such as
3909<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3910Only one type, the return type, is overloaded, and only one type suffix is
3911required. Because the argument's type is matched against the return type, it
3912does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3913
3914<p>To learn how to add an intrinsic function, please see the
3915<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3916</p>
3917
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3918</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3919
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3920<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3921<div class="doc_subsection">
3922 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3923</div>
3924
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3925<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3926
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3927<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3928 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3929intrinsic functions. These functions are related to the similarly
3930named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3931
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3932<p>All of these functions operate on arguments that use a
3933target-specific value type "<tt>va_list</tt>". The LLVM assembly
3934language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3935transformations should be prepared to handle these functions regardless of
3936the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3937
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3938<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]3939instruction and the variable argument handling intrinsic functions are
3940used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3941
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3942<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3943<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3944define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3945 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3946 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3947 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3948 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3949
3950 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3951 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3952
3953 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3954 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3955 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3956 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3957 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3958
3959 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3960 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3961 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3962}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3963
3964declare void @llvm.va_start(i8*)
3965declare void @llvm.va_copy(i8*, i8*)
3966declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3967</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3968</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3969
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3970</div>
3971
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3972<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3973<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3974 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3975</div>
3976
3977
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3978<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3979<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3980<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3981<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3982<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3983<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3984href="#i_va_arg">va_arg</a></tt>.</p>
3985
3986<h5>Arguments:</h5>
3987
3988<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3989
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3990<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3991
3992<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3993macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3994<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]3995<tt>va_arg</tt> will produce the first variable argument passed to the function.
3996Unlike 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]3997last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3998
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3999</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4000
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4001<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4002<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4003 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4004</div>
4005
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4006<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4007<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4008<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4009<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4010
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4011<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4012which 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]4013or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4014
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4015<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4016
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4017<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]4018
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4019<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4020
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4021<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]4022macro available in C. In a target-dependent way, it destroys the
4023<tt>va_list</tt> element to which the argument points. Calls to <a
4024href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4025<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4026<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]4027
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4028</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4029
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4030<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4031<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4032 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4033</div>
4034
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4035<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4036
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4037<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4038
4039<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4040 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4041</pre>
4042
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4043<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4044
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4045<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4046from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4047
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4048<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4049
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4050<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]4051The 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]4052
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4053
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4054<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4055
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4056<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4057macro available in C. In a target-dependent way, it copies the source
4058<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4059intrinsic is necessary because the <tt><a href="#int_va_start">
4060llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4061example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4062
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4063</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4064
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4065<!-- ======================================================================= -->
4066<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4067 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4068</div>
4069
4070<div class="doc_text">
4071
4072<p>
4073LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4074Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4075These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4076stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4077href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4078Front-ends for type-safe garbage collected languages should generate these
4079intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4080href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4081</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4082
4083<p>The garbage collection intrinsics only operate on objects in the generic
4084 address space (address space zero).</p>
4085
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4086</div>
4087
4088<!-- _______________________________________________________________________ -->
4089<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4090 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4091</div>
4092
4093<div class="doc_text">
4094
4095<h5>Syntax:</h5>
4096
4097<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4098 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4099</pre>
4100
4101<h5>Overview:</h5>
4102
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4103<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]4104the code generator, and allows some metadata to be associated with it.</p>
4105
4106<h5>Arguments:</h5>
4107
4108<p>The first argument specifies the address of a stack object that contains the
4109root pointer. The second pointer (which must be either a constant or a global
4110value address) contains the meta-data to be associated with the root.</p>
4111
4112<h5>Semantics:</h5>
4113
4114<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4115location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4116the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4117intrinsic may only be used in a function which <a href="#gc">specifies a GC
4118algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4119
4120</div>
4121
4122
4123<!-- _______________________________________________________________________ -->
4124<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4125 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4126</div>
4127
4128<div class="doc_text">
4129
4130<h5>Syntax:</h5>
4131
4132<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4133 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4134</pre>
4135
4136<h5>Overview:</h5>
4137
4138<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4139locations, allowing garbage collector implementations that require read
4140barriers.</p>
4141
4142<h5>Arguments:</h5>
4143
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4144<p>The second argument is the address to read from, which should be an address
4145allocated from the garbage collector. The first object is a pointer to the
4146start of the referenced object, if needed by the language runtime (otherwise
4147null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4148
4149<h5>Semantics:</h5>
4150
4151<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4152instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4153garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4154may only be used in a function which <a href="#gc">specifies a GC
4155algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4156
4157</div>
4158
4159
4160<!-- _______________________________________________________________________ -->
4161<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4162 <a name="int_gcwrite">'<tt>llvm.gcwrite</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.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4171</pre>
4172
4173<h5>Overview:</h5>
4174
4175<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4176locations, allowing garbage collector implementations that require write
4177barriers (such as generational or reference counting collectors).</p>
4178
4179<h5>Arguments:</h5>
4180
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4181<p>The first argument is the reference to store, the second is the start of the
4182object to store it to, and the third is the address of the field of Obj to
4183store to. If the runtime does not require a pointer to the object, Obj may be
4184null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4185
4186<h5>Semantics:</h5>
4187
4188<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4189instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4190garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4191may only be used in a function which <a href="#gc">specifies a GC
4192algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4193
4194</div>
4195
4196
4197
4198<!-- ======================================================================= -->
4199<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4200 <a name="int_codegen">Code Generator Intrinsics</a>
4201</div>
4202
4203<div class="doc_text">
4204<p>
4205These intrinsics are provided by LLVM to expose special features that may only
4206be implemented with code generator support.
4207</p>
4208
4209</div>
4210
4211<!-- _______________________________________________________________________ -->
4212<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4213 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4214</div>
4215
4216<div class="doc_text">
4217
4218<h5>Syntax:</h5>
4219<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4220 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4221</pre>
4222
4223<h5>Overview:</h5>
4224
4225<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4226The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4227target-specific value indicating the return address of the current function
4228or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4229</p>
4230
4231<h5>Arguments:</h5>
4232
4233<p>
4234The argument to this intrinsic indicates which function to return the address
4235for. Zero indicates the calling function, one indicates its caller, etc. The
4236argument is <b>required</b> to be a constant integer value.
4237</p>
4238
4239<h5>Semantics:</h5>
4240
4241<p>
4242The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4243the return address of the specified call frame, or zero if it cannot be
4244identified. The value returned by this intrinsic is likely to be incorrect or 0
4245for arguments other than zero, so it should only be used for debugging purposes.
4246</p>
4247
4248<p>
4249Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4250aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4251source-language caller.
4252</p>
4253</div>
4254
4255
4256<!-- _______________________________________________________________________ -->
4257<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4258 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4259</div>
4260
4261<div class="doc_text">
4262
4263<h5>Syntax:</h5>
4264<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4265 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4266</pre>
4267
4268<h5>Overview:</h5>
4269
4270<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4271The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4272target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4273</p>
4274
4275<h5>Arguments:</h5>
4276
4277<p>
4278The argument to this intrinsic indicates which function to return the frame
4279pointer for. Zero indicates the calling function, one indicates its caller,
4280etc. The argument is <b>required</b> to be a constant integer value.
4281</p>
4282
4283<h5>Semantics:</h5>
4284
4285<p>
4286The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4287the frame address of the specified call frame, or zero if it cannot be
4288identified. The value returned by this intrinsic is likely to be incorrect or 0
4289for arguments other than zero, so it should only be used for debugging purposes.
4290</p>
4291
4292<p>
4293Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4294aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4295source-language caller.
4296</p>
4297</div>
4298
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4299<!-- _______________________________________________________________________ -->
4300<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4301 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4302</div>
4303
4304<div class="doc_text">
4305
4306<h5>Syntax:</h5>
4307<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4308 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4309</pre>
4310
4311<h5>Overview:</h5>
4312
4313<p>
4314The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4315the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4316<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4317features like scoped automatic variable sized arrays in C99.
4318</p>
4319
4320<h5>Semantics:</h5>
4321
4322<p>
4323This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4324href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4325<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4326<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4327state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4328practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4329that were allocated after the <tt>llvm.stacksave</tt> was executed.
4330</p>
4331
4332</div>
4333
4334<!-- _______________________________________________________________________ -->
4335<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4336 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4337</div>
4338
4339<div class="doc_text">
4340
4341<h5>Syntax:</h5>
4342<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4343 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4344</pre>
4345
4346<h5>Overview:</h5>
4347
4348<p>
4349The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4350the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4351href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4352useful for implementing language features like scoped automatic variable sized
4353arrays in C99.
4354</p>
4355
4356<h5>Semantics:</h5>
4357
4358<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4359See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4360</p>
4361
4362</div>
4363
4364
4365<!-- _______________________________________________________________________ -->
4366<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4367 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4368</div>
4369
4370<div class="doc_text">
4371
4372<h5>Syntax:</h5>
4373<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4374 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]4375</pre>
4376
4377<h5>Overview:</h5>
4378
4379
4380<p>
4381The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4382a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4383no
4384effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4385characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4386</p>
4387
4388<h5>Arguments:</h5>
4389
4390<p>
4391<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4392determining if the fetch should be for a read (0) or write (1), and
4393<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4394locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4395<tt>locality</tt> arguments must be constant integers.
4396</p>
4397
4398<h5>Semantics:</h5>
4399
4400<p>
4401This intrinsic does not modify the behavior of the program. In particular,
4402prefetches cannot trap and do not produce a value. On targets that support this
4403intrinsic, the prefetch can provide hints to the processor cache for better
4404performance.
4405</p>
4406
4407</div>
4408
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4409<!-- _______________________________________________________________________ -->
4410<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4411 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4412</div>
4413
4414<div class="doc_text">
4415
4416<h5>Syntax:</h5>
4417<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4418 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4419</pre>
4420
4421<h5>Overview:</h5>
4422
4423
4424<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4425The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4426(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4427code to simulators and other tools. The method is target specific, but it is
4428expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4429The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4430after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4431optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4432correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4433</p>
4434
4435<h5>Arguments:</h5>
4436
4437<p>
4438<tt>id</tt> is a numerical id identifying the marker.
4439</p>
4440
4441<h5>Semantics:</h5>
4442
4443<p>
4444This intrinsic does not modify the behavior of the program. Backends that do not
4445support this intrinisic may ignore it.
4446</p>
4447
4448</div>
4449
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4450<!-- _______________________________________________________________________ -->
4451<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4452 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4453</div>
4454
4455<div class="doc_text">
4456
4457<h5>Syntax:</h5>
4458<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4459 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4460</pre>
4461
4462<h5>Overview:</h5>
4463
4464
4465<p>
4466The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4467counter register (or similar low latency, high accuracy clocks) on those targets
4468that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4469As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4470should only be used for small timings.
4471</p>
4472
4473<h5>Semantics:</h5>
4474
4475<p>
4476When directly supported, reading the cycle counter should not modify any memory.
4477Implementations are allowed to either return a application specific value or a
4478system wide value. On backends without support, this is lowered to a constant 0.
4479</p>
4480
4481</div>
4482
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4483<!-- ======================================================================= -->
4484<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4485 <a name="int_libc">Standard C Library Intrinsics</a>
4486</div>
4487
4488<div class="doc_text">
4489<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4490LLVM provides intrinsics for a few important standard C library functions.
4491These intrinsics allow source-language front-ends to pass information about the
4492alignment of the pointer arguments to the code generator, providing opportunity
4493for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4494</p>
4495
4496</div>
4497
4498<!-- _______________________________________________________________________ -->
4499<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4500 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4501</div>
4502
4503<div class="doc_text">
4504
4505<h5>Syntax:</h5>
4506<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4507 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4508 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4509 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4510 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4511</pre>
4512
4513<h5>Overview:</h5>
4514
4515<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4516The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4517location to the destination location.
4518</p>
4519
4520<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4521Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4522intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4523</p>
4524
4525<h5>Arguments:</h5>
4526
4527<p>
4528The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4529the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4530specifying the number of bytes to copy, and the fourth argument is the alignment
4531of the source and destination locations.
4532</p>
4533
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4534<p>
4535If 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]4536the caller guarantees that both the source and destination pointers are aligned
4537to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4538</p>
4539
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4540<h5>Semantics:</h5>
4541
4542<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4543The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4544location to the destination location, which are not allowed to overlap. It
4545copies "len" bytes of memory over. If the argument is known to be aligned to
4546some boundary, this can be specified as the fourth argument, otherwise it should
4547be set to 0 or 1.
4548</p>
4549</div>
4550
4551
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4552<!-- _______________________________________________________________________ -->
4553<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4554 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4555</div>
4556
4557<div class="doc_text">
4558
4559<h5>Syntax:</h5>
4560<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4561 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4562 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4563 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4564 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4565</pre>
4566
4567<h5>Overview:</h5>
4568
4569<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4570The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4571location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]4572'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4573</p>
4574
4575<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4576Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4577intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4578</p>
4579
4580<h5>Arguments:</h5>
4581
4582<p>
4583The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4584the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4585specifying the number of bytes to copy, and the fourth argument is the alignment
4586of the source and destination locations.
4587</p>
4588
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4589<p>
4590If 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]4591the caller guarantees that the source and destination pointers are aligned to
4592that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4593</p>
4594
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4595<h5>Semantics:</h5>
4596
4597<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4598The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4599location to the destination location, which may overlap. It
4600copies "len" bytes of memory over. If the argument is known to be aligned to
4601some boundary, this can be specified as the fourth argument, otherwise it should
4602be set to 0 or 1.
4603</p>
4604</div>
4605
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4606
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4607<!-- _______________________________________________________________________ -->
4608<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4609 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4610</div>
4611
4612<div class="doc_text">
4613
4614<h5>Syntax:</h5>
4615<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4616 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4617 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4618 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4619 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4620</pre>
4621
4622<h5>Overview:</h5>
4623
4624<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4625The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4626byte value.
4627</p>
4628
4629<p>
4630Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4631does not return a value, and takes an extra alignment argument.
4632</p>
4633
4634<h5>Arguments:</h5>
4635
4636<p>
4637The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4638byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4639argument specifying the number of bytes to fill, and the fourth argument is the
4640known alignment of destination location.
4641</p>
4642
4643<p>
4644If 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]4645the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4646</p>
4647
4648<h5>Semantics:</h5>
4649
4650<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4651The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4652the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4653destination location. If the argument is known to be aligned to some boundary,
4654this can be specified as the fourth argument, otherwise it should be set to 0 or
46551.
4656</p>
4657</div>
4658
4659
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4660<!-- _______________________________________________________________________ -->
4661<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4662 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4663</div>
4664
4665<div class="doc_text">
4666
4667<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4668<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]4669floating point or vector of floating point type. Not all targets support all
4670types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4671<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4672 declare float @llvm.sqrt.f32(float %Val)
4673 declare double @llvm.sqrt.f64(double %Val)
4674 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4675 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4676 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4677</pre>
4678
4679<h5>Overview:</h5>
4680
4681<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4682The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4683returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4684<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +0000[diff] [blame]4685negative numbers other than -0.0 (which allows for better optimization, because
4686there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
4687defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4688</p>
4689
4690<h5>Arguments:</h5>
4691
4692<p>
4693The argument and return value are floating point numbers of the same type.
4694</p>
4695
4696<h5>Semantics:</h5>
4697
4698<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]4699This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4700floating point number.
4701</p>
4702</div>
4703
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4704<!-- _______________________________________________________________________ -->
4705<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4706 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4707</div>
4708
4709<div class="doc_text">
4710
4711<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4712<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]4713floating point or vector of floating point type. Not all targets support all
4714types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4715<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4716 declare float @llvm.powi.f32(float %Val, i32 %power)
4717 declare double @llvm.powi.f64(double %Val, i32 %power)
4718 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4719 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4720 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4721</pre>
4722
4723<h5>Overview:</h5>
4724
4725<p>
4726The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4727specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4728multiplications is not defined. When a vector of floating point type is
4729used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4730</p>
4731
4732<h5>Arguments:</h5>
4733
4734<p>
4735The second argument is an integer power, and the first is a value to raise to
4736that power.
4737</p>
4738
4739<h5>Semantics:</h5>
4740
4741<p>
4742This function returns the first value raised to the second power with an
4743unspecified sequence of rounding operations.</p>
4744</div>
4745
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4746<!-- _______________________________________________________________________ -->
4747<div class="doc_subsubsection">
4748 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4749</div>
4750
4751<div class="doc_text">
4752
4753<h5>Syntax:</h5>
4754<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4755floating point or vector of floating point type. Not all targets support all
4756types however.
4757<pre>
4758 declare float @llvm.sin.f32(float %Val)
4759 declare double @llvm.sin.f64(double %Val)
4760 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4761 declare fp128 @llvm.sin.f128(fp128 %Val)
4762 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4763</pre>
4764
4765<h5>Overview:</h5>
4766
4767<p>
4768The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4769</p>
4770
4771<h5>Arguments:</h5>
4772
4773<p>
4774The argument and return value are floating point numbers of the same type.
4775</p>
4776
4777<h5>Semantics:</h5>
4778
4779<p>
4780This function returns the sine of the specified operand, returning the
4781same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4782conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4783</div>
4784
4785<!-- _______________________________________________________________________ -->
4786<div class="doc_subsubsection">
4787 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
4788</div>
4789
4790<div class="doc_text">
4791
4792<h5>Syntax:</h5>
4793<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
4794floating point or vector of floating point type. Not all targets support all
4795types however.
4796<pre>
4797 declare float @llvm.cos.f32(float %Val)
4798 declare double @llvm.cos.f64(double %Val)
4799 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4800 declare fp128 @llvm.cos.f128(fp128 %Val)
4801 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4802</pre>
4803
4804<h5>Overview:</h5>
4805
4806<p>
4807The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
4808</p>
4809
4810<h5>Arguments:</h5>
4811
4812<p>
4813The argument and return value are floating point numbers of the same type.
4814</p>
4815
4816<h5>Semantics:</h5>
4817
4818<p>
4819This function returns the cosine of the specified operand, returning the
4820same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4821conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4822</div>
4823
4824<!-- _______________________________________________________________________ -->
4825<div class="doc_subsubsection">
4826 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
4827</div>
4828
4829<div class="doc_text">
4830
4831<h5>Syntax:</h5>
4832<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
4833floating point or vector of floating point type. Not all targets support all
4834types however.
4835<pre>
4836 declare float @llvm.pow.f32(float %Val, float %Power)
4837 declare double @llvm.pow.f64(double %Val, double %Power)
4838 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4839 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4840 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4841</pre>
4842
4843<h5>Overview:</h5>
4844
4845<p>
4846The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4847specified (positive or negative) power.
4848</p>
4849
4850<h5>Arguments:</h5>
4851
4852<p>
4853The second argument is a floating point power, and the first is a value to
4854raise to that power.
4855</p>
4856
4857<h5>Semantics:</h5>
4858
4859<p>
4860This function returns the first value raised to the second power,
4861returning the
4862same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4863conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4864</div>
4865
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4866
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4867<!-- ======================================================================= -->
4868<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4869 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4870</div>
4871
4872<div class="doc_text">
4873<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4874LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4875These allow efficient code generation for some algorithms.
4876</p>
4877
4878</div>
4879
4880<!-- _______________________________________________________________________ -->
4881<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4882 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4883</div>
4884
4885<div class="doc_text">
4886
4887<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4888<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4889type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4890<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4891 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4892 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4893 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4894</pre>
4895
4896<h5>Overview:</h5>
4897
4898<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4899The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4900values with an even number of bytes (positive multiple of 16 bits). These are
4901useful for performing operations on data that is not in the target's native
4902byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4903</p>
4904
4905<h5>Semantics:</h5>
4906
4907<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4908The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4909and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4910intrinsic returns an i32 value that has the four bytes of the input i32
4911swapped, 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]4912i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4913<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4914additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4915</p>
4916
4917</div>
4918
4919<!-- _______________________________________________________________________ -->
4920<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4921 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4922</div>
4923
4924<div class="doc_text">
4925
4926<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4927<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4928width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4929<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4930 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4931 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4932 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4933 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4934 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4935</pre>
4936
4937<h5>Overview:</h5>
4938
4939<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4940The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4941value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4942</p>
4943
4944<h5>Arguments:</h5>
4945
4946<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4947The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4948integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4949</p>
4950
4951<h5>Semantics:</h5>
4952
4953<p>
4954The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4955</p>
4956</div>
4957
4958<!-- _______________________________________________________________________ -->
4959<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4960 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4961</div>
4962
4963<div class="doc_text">
4964
4965<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4966<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4967integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4968<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4969 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4970 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4971 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4972 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4973 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4974</pre>
4975
4976<h5>Overview:</h5>
4977
4978<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4979The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4980leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4981</p>
4982
4983<h5>Arguments:</h5>
4984
4985<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4986The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4987integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4988</p>
4989
4990<h5>Semantics:</h5>
4991
4992<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4993The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4994in 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]4995of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4996</p>
4997</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4998
4999
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5000
5001<!-- _______________________________________________________________________ -->
5002<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]5003 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5004</div>
5005
5006<div class="doc_text">
5007
5008<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]5009<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5010integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5011<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5012 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5013 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]5014 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5015 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5016 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5017</pre>
5018
5019<h5>Overview:</h5>
5020
5021<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]5022The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5023trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5024</p>
5025
5026<h5>Arguments:</h5>
5027
5028<p>
5029The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]5030integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]5031</p>
5032
5033<h5>Semantics:</h5>
5034
5035<p>
5036The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5037in a variable. If the src == 0 then the result is the size in bits of the type
5038of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5039</p>
5040</div>
5041
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5042<!-- _______________________________________________________________________ -->
5043<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5044 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5045</div>
5046
5047<div class="doc_text">
5048
5049<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5050<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5051on any integer bit width.
5052<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5053 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5054 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5055</pre>
5056
5057<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5058<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5059range of bits from an integer value and returns them in the same bit width as
5060the original value.</p>
5061
5062<h5>Arguments:</h5>
5063<p>The first argument, <tt>%val</tt> and the result may be integer types of
5064any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5065arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5066
5067<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5068<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5069of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5070<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5071operates in forward mode.</p>
5072<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5073right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5074only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5075<ol>
5076 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5077 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5078 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5079 to determine the number of bits to retain.</li>
5080 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5081 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5082</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5083<p>In reverse mode, a similar computation is made except that the bits are
5084returned in the reverse order. So, for example, if <tt>X</tt> has the value
5085<tt>i16 0x0ACF (101011001111)</tt> and we apply
5086<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5087<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5088</div>
5089
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5090<div class="doc_subsubsection">
5091 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5092</div>
5093
5094<div class="doc_text">
5095
5096<h5>Syntax:</h5>
5097<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5098on any integer bit width.
5099<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5100 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5101 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]5102</pre>
5103
5104<h5>Overview:</h5>
5105<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5106of bits in an integer value with another integer value. It returns the integer
5107with the replaced bits.</p>
5108
5109<h5>Arguments:</h5>
5110<p>The first argument, <tt>%val</tt> and the result may be integer types of
5111any bit width but they must have the same bit width. <tt>%val</tt> is the value
5112whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5113integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5114type since they specify only a bit index.</p>
5115
5116<h5>Semantics:</h5>
5117<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5118of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5119<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5120operates in forward mode.</p>
5121<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5122truncating it down to the size of the replacement area or zero extending it
5123up to that size.</p>
5124<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5125are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5126in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5127to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5128<p>In reverse mode, a similar computation is made except that the bits are
5129reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5130<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]5131<h5>Examples:</h5>
5132<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5133 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5134 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5135 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5136 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5137 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5138</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5139</div>
5140
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5141<!-- ======================================================================= -->
5142<div class="doc_subsection">
5143 <a name="int_debugger">Debugger Intrinsics</a>
5144</div>
5145
5146<div class="doc_text">
5147<p>
5148The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5149are described in the <a
5150href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5151Debugging</a> document.
5152</p>
5153</div>
5154
5155
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5156<!-- ======================================================================= -->
5157<div class="doc_subsection">
5158 <a name="int_eh">Exception Handling Intrinsics</a>
5159</div>
5160
5161<div class="doc_text">
5162<p> The LLVM exception handling intrinsics (which all start with
5163<tt>llvm.eh.</tt> prefix), are described in the <a
5164href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5165Handling</a> document. </p>
5166</div>
5167
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5168<!-- ======================================================================= -->
5169<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5170 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5171</div>
5172
5173<div class="doc_text">
5174<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5175 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5176 the <tt>nest</tt> attribute, from a function. The result is a callable
5177 function pointer lacking the nest parameter - the caller does not need
5178 to provide a value for it. Instead, the value to use is stored in
5179 advance in a "trampoline", a block of memory usually allocated
5180 on the stack, which also contains code to splice the nest value into the
5181 argument list. This is used to implement the GCC nested function address
5182 extension.
5183</p>
5184<p>
5185 For example, if the function is
5186 <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]5187 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]5188<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5189 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5190 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5191 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5192 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5193</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5194 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5195 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5196</div>
5197
5198<!-- _______________________________________________________________________ -->
5199<div class="doc_subsubsection">
5200 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5201</div>
5202<div class="doc_text">
5203<h5>Syntax:</h5>
5204<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5205declare 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]5206</pre>
5207<h5>Overview:</h5>
5208<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5209 This fills the memory pointed to by <tt>tramp</tt> with code
5210 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5211</p>
5212<h5>Arguments:</h5>
5213<p>
5214 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5215 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5216 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5217 intrinsic. Note that the size and the alignment are target-specific - LLVM
5218 currently provides no portable way of determining them, so a front-end that
5219 generates this intrinsic needs to have some target-specific knowledge.
5220 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]5221</p>
5222<h5>Semantics:</h5>
5223<p>
5224 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5225 dependent code, turning it into a function. A pointer to this function is
5226 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5227 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5228 before being called. The new function's signature is the same as that of
5229 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5230 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5231 of pointer type. Calling the new function is equivalent to calling
5232 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5233 missing <tt>nest</tt> argument. If, after calling
5234 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5235 modified, then the effect of any later call to the returned function pointer is
5236 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5237</p>
5238</div>
5239
5240<!-- ======================================================================= -->
5241<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame^]5242 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5243</div>
5244
5245<div class="doc_text">
5246<p>
5247 These intrinsic functions expand the "universal IR" of LLVM to represent
5248 hardware constructs for atomic operations and memory synchronization. This
5249 provides an interface to the hardware, not an interface to the programmer. It
5250 is aimed at a low enough level to allow any programming models or APIs which
5251 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5252 hardware behavior. Just as hardware provides a "universal IR" for source
5253 languages, it also provides a starting point for developing a "universal"
5254 atomic operation and synchronization IR.
5255</p>
5256<p>
5257 These do <em>not</em> form an API such as high-level threading libraries,
5258 software transaction memory systems, atomic primitives, and intrinsic
5259 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5260 application libraries. The hardware interface provided by LLVM should allow
5261 a clean implementation of all of these APIs and parallel programming models.
5262 No one model or paradigm should be selected above others unless the hardware
5263 itself ubiquitously does so.
5264
5265</p>
5266</div>
5267
5268<!-- _______________________________________________________________________ -->
5269<div class="doc_subsubsection">
5270 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5271</div>
5272<div class="doc_text">
5273<h5>Syntax:</h5>
5274<pre>
5275declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5276i1 &lt;device&gt; )
5277
5278</pre>
5279<h5>Overview:</h5>
5280<p>
5281 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5282 specific pairs of memory access types.
5283</p>
5284<h5>Arguments:</h5>
5285<p>
5286 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5287 The first four arguments enables a specific barrier as listed below. The fith
5288 argument specifies that the barrier applies to io or device or uncached memory.
5289
5290</p>
5291 <ul>
5292 <li><tt>ll</tt>: load-load barrier</li>
5293 <li><tt>ls</tt>: load-store barrier</li>
5294 <li><tt>sl</tt>: store-load barrier</li>
5295 <li><tt>ss</tt>: store-store barrier</li>
5296 <li><tt>device</tt>: barrier applies to device and uncached memory also.
5297 </ul>
5298<h5>Semantics:</h5>
5299<p>
5300 This intrinsic causes the system to enforce some ordering constraints upon
5301 the loads and stores of the program. This barrier does not indicate
5302 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5303 which they occur. For any of the specified pairs of load and store operations
5304 (f.ex. load-load, or store-load), all of the first operations preceding the
5305 barrier will complete before any of the second operations succeeding the
5306 barrier begin. Specifically the semantics for each pairing is as follows:
5307</p>
5308 <ul>
5309 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5310 after the barrier begins.</li>
5311
5312 <li><tt>ls</tt>: All loads before the barrier must complete before any
5313 store after the barrier begins.</li>
5314 <li><tt>ss</tt>: All stores before the barrier must complete before any
5315 store after the barrier begins.</li>
5316 <li><tt>sl</tt>: All stores before the barrier must complete before any
5317 load after the barrier begins.</li>
5318 </ul>
5319<p>
5320 These semantics are applied with a logical "and" behavior when more than one
5321 is enabled in a single memory barrier intrinsic.
5322</p>
5323<p>
5324 Backends may implement stronger barriers than those requested when they do not
5325 support as fine grained a barrier as requested. Some architectures do not
5326 need all types of barriers and on such architectures, these become noops.
5327</p>
5328<h5>Example:</h5>
5329<pre>
5330%ptr = malloc i32
5331 store i32 4, %ptr
5332
5333%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5334 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5335 <i>; guarantee the above finishes</i>
5336 store i32 8, %ptr <i>; before this begins</i>
5337</pre>
5338</div>
5339
5340
5341<!-- ======================================================================= -->
5342<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5343 <a name="int_general">General Intrinsics</a>
5344</div>
5345
5346<div class="doc_text">
5347<p> This class of intrinsics is designed to be generic and has
5348no specific purpose. </p>
5349</div>
5350
5351<!-- _______________________________________________________________________ -->
5352<div class="doc_subsubsection">
5353 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5354</div>
5355
5356<div class="doc_text">
5357
5358<h5>Syntax:</h5>
5359<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5360 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]5361</pre>
5362
5363<h5>Overview:</h5>
5364
5365<p>
5366The '<tt>llvm.var.annotation</tt>' intrinsic
5367</p>
5368
5369<h5>Arguments:</h5>
5370
5371<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5372The first argument is a pointer to a value, the second is a pointer to a
5373global string, the third is a pointer to a global string which is the source
5374file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5375</p>
5376
5377<h5>Semantics:</h5>
5378
5379<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5380This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5381This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5382annotations. These have no other defined use, they are ignored by code
5383generation and optimization.
5384</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5385</div>
5386
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5387<!-- _______________________________________________________________________ -->
5388<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5389 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5390</div>
5391
5392<div class="doc_text">
5393
5394<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5395<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5396any integer bit width.
5397</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5398<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]5399 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5400 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5401 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5402 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5403 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]5404</pre>
5405
5406<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5407
5408<p>
5409The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5410</p>
5411
5412<h5>Arguments:</h5>
5413
5414<p>
5415The first argument is an integer value (result of some expression),
5416the second is a pointer to a global string, the third is a pointer to a global
5417string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5418It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5419</p>
5420
5421<h5>Semantics:</h5>
5422
5423<p>
5424This intrinsic allows annotations to be put on arbitrary expressions
5425with arbitrary strings. This can be useful for special purpose optimizations
5426that want to look for these annotations. These have no other defined use, they
5427are ignored by code generation and optimization.
5428</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5429
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]5430<!-- _______________________________________________________________________ -->
5431<div class="doc_subsubsection">
5432 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
5433</div>
5434
5435<div class="doc_text">
5436
5437<h5>Syntax:</h5>
5438<pre>
5439 declare void @llvm.trap()
5440</pre>
5441
5442<h5>Overview:</h5>
5443
5444<p>
5445The '<tt>llvm.trap</tt>' intrinsic
5446</p>
5447
5448<h5>Arguments:</h5>
5449
5450<p>
5451None
5452</p>
5453
5454<h5>Semantics:</h5>
5455
5456<p>
5457This intrinsics is lowered to the target dependent trap instruction. If the
5458target does not have a trap instruction, this intrinsic will be lowered to the
5459call of the abort() function.
5460</p>
5461</div>
5462
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5463<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5464<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5465<address>
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5467 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5468 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]5469 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5470
5471 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]5472 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5473 Last modified: $Date$
5474</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]5475
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5476</body>
5477</html>