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gerrit-public.fairphone.software / toolchain / llvm-project / 4d70ba313408957ed5614d06cb887b071d5f3576 / . / 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>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]207 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]208 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]209 <li><a href="#int_var_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]210 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]211 </ol>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]212 <ol>
213 <li><a href="#int_annotation">
Tanya Lattner08abc812007-09-22 00:01:26 +0000[diff] [blame]214 <tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]215 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]216 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 </ol>
218 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]219</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]220
221<div class="doc_author">
222 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
223 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]224</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]225
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]226<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]227<div class="doc_section"> <a name="abstract">Abstract </a></div>
228<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]229
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]230<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]231<p>This document is a reference manual for the LLVM assembly language.
232LLVM is an SSA based representation that provides type safety,
233low-level operations, flexibility, and the capability of representing
234'all' high-level languages cleanly. It is the common code
235representation used throughout all phases of the LLVM compilation
236strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]237</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]238
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]239<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]240<div class="doc_section"> <a name="introduction">Introduction</a> </div>
241<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]242
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]243<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]244
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]245<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]246different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]247representation (suitable for fast loading by a Just-In-Time compiler),
248and as a human readable assembly language representation. This allows
249LLVM to provide a powerful intermediate representation for efficient
250compiler transformations and analysis, while providing a natural means
251to debug and visualize the transformations. The three different forms
252of LLVM are all equivalent. This document describes the human readable
253representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]254
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]255<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]256while being expressive, typed, and extensible at the same time. It
257aims to be a "universal IR" of sorts, by being at a low enough level
258that high-level ideas may be cleanly mapped to it (similar to how
259microprocessors are "universal IR's", allowing many source languages to
260be mapped to them). By providing type information, LLVM can be used as
261the target of optimizations: for example, through pointer analysis, it
262can be proven that a C automatic variable is never accessed outside of
263the current function... allowing it to be promoted to a simple SSA
264value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]265
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]266</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]267
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]268<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]269<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]271<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]272
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]273<p>It is important to note that this document describes 'well formed'
274LLVM assembly language. There is a difference between what the parser
275accepts and what is considered 'well formed'. For example, the
276following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]277
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]278<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]279<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]280%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]281</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]282</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]283
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]284<p>...because the definition of <tt>%x</tt> does not dominate all of
285its uses. The LLVM infrastructure provides a verification pass that may
286be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]287automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]288the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]289by the verifier pass indicate bugs in transformation passes or input to
290the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]291</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]293<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]294
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]295<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]296<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]297<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]298
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]299<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]300
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]301 <p>LLVM identifiers come in two basic types: global and local. Global
302 identifiers (functions, global variables) begin with the @ character. Local
303 identifiers (register names, types) begin with the % character. Additionally,
304 there are three different formats for identifiers, for different purposes:
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]305
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]306<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]307 <li>Named values are represented as a string of characters with their prefix.
308 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
309 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]310 Identifiers which require other characters in their names can be surrounded
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]311 with quotes. In this way, anything except a <tt>&quot;</tt> character can
312 be used in a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]313
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]314 <li>Unnamed values are represented as an unsigned numeric value with their
315 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]316
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]317 <li>Constants, which are described in a <a href="#constants">section about
318 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]319</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]320
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]321<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]322don't need to worry about name clashes with reserved words, and the set of
323reserved words may be expanded in the future without penalty. Additionally,
324unnamed identifiers allow a compiler to quickly come up with a temporary
325variable without having to avoid symbol table conflicts.</p>
326
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]327<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]328languages. There are keywords for different opcodes
329('<tt><a href="#i_add">add</a></tt>',
330 '<tt><a href="#i_bitcast">bitcast</a></tt>',
331 '<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]332href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]333and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]334none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]335
336<p>Here is an example of LLVM code to multiply the integer variable
337'<tt>%X</tt>' by 8:</p>
338
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]339<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]340
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]341<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]342<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]343%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]344</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]345</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]346
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]347<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]348
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]349<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]350<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]351%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]352</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]353</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]354
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]355<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]356
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]357<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]358<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]359<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
360<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
361%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]362</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]363</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]364
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]365<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
366important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]367
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]368<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]369
370 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
371 line.</li>
372
373 <li>Unnamed temporaries are created when the result of a computation is not
374 assigned to a named value.</li>
375
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]376 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]377
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]378</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]379
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]380<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]381demonstrating instructions, we will follow an instruction with a comment that
382defines the type and name of value produced. Comments are shown in italic
383text.</p>
384
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]385</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]386
387<!-- *********************************************************************** -->
388<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
389<!-- *********************************************************************** -->
390
391<!-- ======================================================================= -->
392<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
393</div>
394
395<div class="doc_text">
396
397<p>LLVM programs are composed of "Module"s, each of which is a
398translation unit of the input programs. Each module consists of
399functions, global variables, and symbol table entries. Modules may be
400combined together with the LLVM linker, which merges function (and
401global variable) definitions, resolves forward declarations, and merges
402symbol table entries. Here is an example of the "hello world" module:</p>
403
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]404<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]405<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]406<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
407 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]408
409<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]410<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]411
412<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]413define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]414 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]415 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]416 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]417
418 <i>; Call puts function to write out the string to stdout...</i>
419 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]420 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]421 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]422 href="#i_ret">ret</a> i32 0<br>}<br>
423</pre>
424</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]425
426<p>This example is made up of a <a href="#globalvars">global variable</a>
427named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
428function, and a <a href="#functionstructure">function definition</a>
429for "<tt>main</tt>".</p>
430
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]431<p>In general, a module is made up of a list of global values,
432where both functions and global variables are global values. Global values are
433represented by a pointer to a memory location (in this case, a pointer to an
434array of char, and a pointer to a function), and have one of the following <a
435href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]436
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437</div>
438
439<!-- ======================================================================= -->
440<div class="doc_subsection">
441 <a name="linkage">Linkage Types</a>
442</div>
443
444<div class="doc_text">
445
446<p>
447All Global Variables and Functions have one of the following types of linkage:
448</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]449
450<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]452 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]453
454 <dd>Global values with internal linkage are only directly accessible by
455 objects in the current module. In particular, linking code into a module with
456 an internal global value may cause the internal to be renamed as necessary to
457 avoid collisions. Because the symbol is internal to the module, all
458 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]459 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]460 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]461
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]462 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]464 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
465 the same name when linkage occurs. This is typically used to implement
466 inline functions, templates, or other code which must be generated in each
467 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
468 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]469 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]471 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]472
473 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
474 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]475 used for globals that may be emitted in multiple translation units, but that
476 are not guaranteed to be emitted into every translation unit that uses them.
477 One example of this are common globals in C, such as "<tt>int X;</tt>" at
478 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]479 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]480
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]481 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]482
483 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
484 pointer to array type. When two global variables with appending linkage are
485 linked together, the two global arrays are appended together. This is the
486 LLVM, typesafe, equivalent of having the system linker append together
487 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]488 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]489
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]490 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
491 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
492 until linked, if not linked, the symbol becomes null instead of being an
493 undefined reference.
494 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]495
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]496 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]497
498 <dd>If none of the above identifiers are used, the global is externally
499 visible, meaning that it participates in linkage and can be used to resolve
500 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]501 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]502</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]503
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]504 <p>
505 The next two types of linkage are targeted for Microsoft Windows platform
506 only. They are designed to support importing (exporting) symbols from (to)
507 DLLs.
508 </p>
509
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]510 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]511 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
512
513 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
514 or variable via a global pointer to a pointer that is set up by the DLL
515 exporting the symbol. On Microsoft Windows targets, the pointer name is
516 formed by combining <code>_imp__</code> and the function or variable name.
517 </dd>
518
519 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
520
521 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
522 pointer to a pointer in a DLL, so that it can be referenced with the
523 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
524 name is formed by combining <code>_imp__</code> and the function or variable
525 name.
526 </dd>
527
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]528</dl>
529
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]530<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]531variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
532variable and was linked with this one, one of the two would be renamed,
533preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
534external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]535outside of the current module.</p>
536<p>It is illegal for a function <i>declaration</i>
537to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]538or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]539<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
540linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]541</div>
542
543<!-- ======================================================================= -->
544<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]545 <a name="callingconv">Calling Conventions</a>
546</div>
547
548<div class="doc_text">
549
550<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
551and <a href="#i_invoke">invokes</a> can all have an optional calling convention
552specified for the call. The calling convention of any pair of dynamic
553caller/callee must match, or the behavior of the program is undefined. The
554following calling conventions are supported by LLVM, and more may be added in
555the future:</p>
556
557<dl>
558 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
559
560 <dd>This calling convention (the default if no other calling convention is
561 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]562 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]563 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]564 </dd>
565
566 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
567
568 <dd>This calling convention attempts to make calls as fast as possible
569 (e.g. by passing things in registers). This calling convention allows the
570 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]571 without having to conform to an externally specified ABI. Implementations of
572 this convention should allow arbitrary tail call optimization to be supported.
573 This calling convention does not support varargs and requires the prototype of
574 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]575 </dd>
576
577 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
578
579 <dd>This calling convention attempts to make code in the caller as efficient
580 as possible under the assumption that the call is not commonly executed. As
581 such, these calls often preserve all registers so that the call does not break
582 any live ranges in the caller side. This calling convention does not support
583 varargs and requires the prototype of all callees to exactly match the
584 prototype of the function definition.
585 </dd>
586
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]587 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]588
589 <dd>Any calling convention may be specified by number, allowing
590 target-specific calling conventions to be used. Target specific calling
591 conventions start at 64.
592 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]593</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]594
595<p>More calling conventions can be added/defined on an as-needed basis, to
596support pascal conventions or any other well-known target-independent
597convention.</p>
598
599</div>
600
601<!-- ======================================================================= -->
602<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]603 <a name="visibility">Visibility Styles</a>
604</div>
605
606<div class="doc_text">
607
608<p>
609All Global Variables and Functions have one of the following visibility styles:
610</p>
611
612<dl>
613 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
614
615 <dd>On ELF, default visibility means that the declaration is visible to other
616 modules and, in shared libraries, means that the declared entity may be
617 overridden. On Darwin, default visibility means that the declaration is
618 visible to other modules. Default visibility corresponds to "external
619 linkage" in the language.
620 </dd>
621
622 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
623
624 <dd>Two declarations of an object with hidden visibility refer to the same
625 object if they are in the same shared object. Usually, hidden visibility
626 indicates that the symbol will not be placed into the dynamic symbol table,
627 so no other module (executable or shared library) can reference it
628 directly.
629 </dd>
630
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]631 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
632
633 <dd>On ELF, protected visibility indicates that the symbol will be placed in
634 the dynamic symbol table, but that references within the defining module will
635 bind to the local symbol. That is, the symbol cannot be overridden by another
636 module.
637 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]638</dl>
639
640</div>
641
642<!-- ======================================================================= -->
643<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]644 <a name="globalvars">Global Variables</a>
645</div>
646
647<div class="doc_text">
648
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]649<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]650instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]651an explicit section to be placed in, and may have an optional explicit alignment
652specified. A variable may be defined as "thread_local", which means that it
653will not be shared by threads (each thread will have a separated copy of the
654variable). A variable may be defined as a global "constant," which indicates
655that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]656optimization, allowing the global data to be placed in the read-only section of
657an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]658cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]659
660<p>
661LLVM explicitly allows <em>declarations</em> of global variables to be marked
662constant, even if the final definition of the global is not. This capability
663can be used to enable slightly better optimization of the program, but requires
664the language definition to guarantee that optimizations based on the
665'constantness' are valid for the translation units that do not include the
666definition.
667</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]668
669<p>As SSA values, global variables define pointer values that are in
670scope (i.e. they dominate) all basic blocks in the program. Global
671variables always define a pointer to their "content" type because they
672describe a region of memory, and all memory objects in LLVM are
673accessed through pointers.</p>
674
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]675<p>A global variable may be declared to reside in a target-specifc numbered
676address space. For targets that support them, address spaces may affect how
677optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000[diff] [blame]678the variable. The default address space is zero. The address space qualifier
679must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]680
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]681<p>LLVM allows an explicit section to be specified for globals. If the target
682supports it, it will emit globals to the section specified.</p>
683
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]684<p>An explicit alignment may be specified for a global. If not present, or if
685the alignment is set to zero, the alignment of the global is set by the target
686to whatever it feels convenient. If an explicit alignment is specified, the
687global is forced to have at least that much alignment. All alignments must be
688a power of 2.</p>
689
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]690<p>For example, the following defines a global in a numbered address space with
691an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]692
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]693<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]694<pre>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]695@G = constant float 1.0 addrspace(5), section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]696</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]697</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]698
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]699</div>
700
701
702<!-- ======================================================================= -->
703<div class="doc_subsection">
704 <a name="functionstructure">Functions</a>
705</div>
706
707<div class="doc_text">
708
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]709<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
710an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]711<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]712<a href="#callingconv">calling convention</a>, a return type, an optional
713<a href="#paramattrs">parameter attribute</a> for the return type, a function
714name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]715<a href="#paramattrs">parameter attributes</a>), an optional section, an
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]716optional alignment, an optional <a href="#gc">garbage collector name</a>, an
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]717opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]718
719LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
720optional <a href="#linkage">linkage type</a>, an optional
721<a href="#visibility">visibility style</a>, an optional
722<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]723<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]724name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000[diff] [blame]725<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]726
727<p>A function definition contains a list of basic blocks, forming the CFG for
728the function. Each basic block may optionally start with a label (giving the
729basic block a symbol table entry), contains a list of instructions, and ends
730with a <a href="#terminators">terminator</a> instruction (such as a branch or
731function return).</p>
732
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]733<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]734executed on entrance to the function, and it is not allowed to have predecessor
735basic blocks (i.e. there can not be any branches to the entry block of a
736function). Because the block can have no predecessors, it also cannot have any
737<a href="#i_phi">PHI nodes</a>.</p>
738
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]739<p>LLVM allows an explicit section to be specified for functions. If the target
740supports it, it will emit functions to the section specified.</p>
741
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]742<p>An explicit alignment may be specified for a function. If not present, or if
743the alignment is set to zero, the alignment of the function is set by the target
744to whatever it feels convenient. If an explicit alignment is specified, the
745function is forced to have at least that much alignment. All alignments must be
746a power of 2.</p>
747
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]748</div>
749
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]750
751<!-- ======================================================================= -->
752<div class="doc_subsection">
753 <a name="aliasstructure">Aliases</a>
754</div>
755<div class="doc_text">
756 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikovb18f8f82007-04-28 13:45:00 +0000[diff] [blame]757 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]758 optional <a href="#linkage">linkage type</a>, and an
759 optional <a href="#visibility">visibility style</a>.</p>
760
761 <h5>Syntax:</h5>
762
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]763<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]764<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]765@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]766</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]767</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]768
769</div>
770
771
772
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]773<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]774<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
775<div class="doc_text">
776 <p>The return type and each parameter of a function type may have a set of
777 <i>parameter attributes</i> associated with them. Parameter attributes are
778 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]779 a function. Parameter attributes are considered to be part of the function,
780 not of the function type, so functions with different parameter attributes
781 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]782
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]783 <p>Parameter attributes are simple keywords that follow the type specified. If
784 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]785 example:</p>
786
787<div class="doc_code">
788<pre>
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]789declare i32 @printf(i8* noalias , ...) nounwind
790declare i32 @atoi(i8*) nounwind readonly
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]791</pre>
792</div>
793
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000[diff] [blame]794 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
795 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]796
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]797 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]798 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]799 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]800 <dd>This indicates that the parameter should be zero extended just before
801 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]802
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]803 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]804 <dd>This indicates that the parameter should be sign extended just before
805 a call to this function.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]806
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]807 <dt><tt>inreg</tt></dt>
808 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]809 possible) during assembling function call. Support for this attribute is
810 target-specific</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]811
812 <dt><tt>byval</tt></dt>
813 <dd>This indicates that the pointer parameter is really an aggregate that
814 was passed by value to the function. The attribute implies that a hidden
815 copy of the struct is made between the caller and the callee, so the
816 callee is unable to modify the struct in the callee. This attribute is only
817 valid on llvm pointer arguments.</dd>
818
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]819 <dt><tt>sret</tt></dt>
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]820 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]821 that is the return value of the function in the source program.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]822
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]823 <dt><tt>noalias</tt></dt>
824 <dd>This indicates that the parameter not alias any other object or any
825 other "noalias" objects during the function call.
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]826
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]827 <dt><tt>noreturn</tt></dt>
828 <dd>This function attribute indicates that the function never returns. This
829 indicates to LLVM that every call to this function should be treated as if
830 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]831
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]832 <dt><tt>nounwind</tt></dt>
833 <dd>This function attribute indicates that the function type does not use
834 the unwind instruction and does not allow stack unwinding to propagate
835 through it.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]836
Duncan Sands27e91592007-07-27 19:57:41 +0000[diff] [blame]837 <dt><tt>nest</tt></dt>
838 <dd>This indicates that the parameter can be excised using the
839 <a href="#int_trampoline">trampoline intrinsics</a>.</dd>
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]840 <dt><tt>readonly</tt></dt>
Duncan Sands730a3262007-11-14 21:14:02 +0000[diff] [blame]841 <dd>This function attribute indicates that the function has no side-effects
Duncan Sandsa89a1132007-11-22 20:23:04 +0000[diff] [blame]842 except for producing a return value or throwing an exception. The value
843 returned must only depend on the function arguments and/or global variables.
844 It may use values obtained by dereferencing pointers.</dd>
845 <dt><tt>readnone</tt></dt>
846 <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]847 function, but in addition it is not allowed to dereference any pointer arguments
848 or global variables.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]849 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]850
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]851</div>
852
853<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]854<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]855 <a name="gc">Garbage Collector Names</a>
856</div>
857
858<div class="doc_text">
859<p>Each function may specify a garbage collector name, which is simply a
860string.</p>
861
862<div class="doc_code"><pre
863>define void @f() gc "name" { ...</pre></div>
864
865<p>The compiler declares the supported values of <i>name</i>. Specifying a
866collector which will cause the compiler to alter its output in order to support
867the named garbage collection algorithm.</p>
868</div>
869
870<!-- ======================================================================= -->
871<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]872 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]873</div>
874
875<div class="doc_text">
876<p>
877Modules may contain "module-level inline asm" blocks, which corresponds to the
878GCC "file scope inline asm" blocks. These blocks are internally concatenated by
879LLVM and treated as a single unit, but may be separated in the .ll file if
880desired. The syntax is very simple:
881</p>
882
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]883<div class="doc_code">
884<pre>
885module asm "inline asm code goes here"
886module asm "more can go here"
887</pre>
888</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]889
890<p>The strings can contain any character by escaping non-printable characters.
891 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
892 for the number.
893</p>
894
895<p>
896 The inline asm code is simply printed to the machine code .s file when
897 assembly code is generated.
898</p>
899</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]900
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]901<!-- ======================================================================= -->
902<div class="doc_subsection">
903 <a name="datalayout">Data Layout</a>
904</div>
905
906<div class="doc_text">
907<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]908data is to be laid out in memory. The syntax for the data layout is simply:</p>
909<pre> target datalayout = "<i>layout specification</i>"</pre>
910<p>The <i>layout specification</i> consists of a list of specifications
911separated by the minus sign character ('-'). Each specification starts with a
912letter and may include other information after the letter to define some
913aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]914<dl>
915 <dt><tt>E</tt></dt>
916 <dd>Specifies that the target lays out data in big-endian form. That is, the
917 bits with the most significance have the lowest address location.</dd>
918 <dt><tt>e</tt></dt>
919 <dd>Specifies that hte target lays out data in little-endian form. That is,
920 the bits with the least significance have the lowest address location.</dd>
921 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
922 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
923 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
924 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
925 too.</dd>
926 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
927 <dd>This specifies the alignment for an integer type of a given bit
928 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
929 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
930 <dd>This specifies the alignment for a vector type of a given bit
931 <i>size</i>.</dd>
932 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
933 <dd>This specifies the alignment for a floating point type of a given bit
934 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
935 (double).</dd>
936 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
937 <dd>This specifies the alignment for an aggregate type of a given bit
938 <i>size</i>.</dd>
939</dl>
940<p>When constructing the data layout for a given target, LLVM starts with a
941default set of specifications which are then (possibly) overriden by the
942specifications in the <tt>datalayout</tt> keyword. The default specifications
943are given in this list:</p>
944<ul>
945 <li><tt>E</tt> - big endian</li>
946 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
947 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
948 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
949 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
950 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
951 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
952 alignment of 64-bits</li>
953 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
954 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
955 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
956 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
957 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
958</ul>
959<p>When llvm is determining the alignment for a given type, it uses the
960following rules:
961<ol>
962 <li>If the type sought is an exact match for one of the specifications, that
963 specification is used.</li>
964 <li>If no match is found, and the type sought is an integer type, then the
965 smallest integer type that is larger than the bitwidth of the sought type is
966 used. If none of the specifications are larger than the bitwidth then the the
967 largest integer type is used. For example, given the default specifications
968 above, the i7 type will use the alignment of i8 (next largest) while both
969 i65 and i256 will use the alignment of i64 (largest specified).</li>
970 <li>If no match is found, and the type sought is a vector type, then the
971 largest vector type that is smaller than the sought vector type will be used
972 as a fall back. This happens because <128 x double> can be implemented in
973 terms of 64 <2 x double>, for example.</li>
974</ol>
975</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]976
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]977<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]978<div class="doc_section"> <a name="typesystem">Type System</a> </div>
979<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]980
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]981<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]982
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]983<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]984intermediate representation. Being typed enables a number of
985optimizations to be performed on the IR directly, without having to do
986extra analyses on the side before the transformation. A strong type
987system makes it easier to read the generated code and enables novel
988analyses and transformations that are not feasible to perform on normal
989three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]990
991</div>
992
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]993<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]994<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]995Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]996<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]997<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]998classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]999
1000<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1001 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1002 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1003 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1004 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1005 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1006 </tr>
1007 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1008 <td><a href="#t_floating">floating point</a></td>
1009 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1010 </tr>
1011 <tr>
1012 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1013 <td><a href="#t_integer">integer</a>,
1014 <a href="#t_floating">floating point</a>,
1015 <a href="#t_pointer">pointer</a>,
1016 <a href="#t_vector">vector</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1017 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1018 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1019 <tr>
1020 <td><a href="#t_primitive">primitive</a></td>
1021 <td><a href="#t_label">label</a>,
1022 <a href="#t_void">void</a>,
1023 <a href="#t_integer">integer</a>,
1024 <a href="#t_floating">floating point</a>.</td>
1025 </tr>
1026 <tr>
1027 <td><a href="#t_derived">derived</a></td>
1028 <td><a href="#t_integer">integer</a>,
1029 <a href="#t_array">array</a>,
1030 <a href="#t_function">function</a>,
1031 <a href="#t_pointer">pointer</a>,
1032 <a href="#t_struct">structure</a>,
1033 <a href="#t_pstruct">packed structure</a>,
1034 <a href="#t_vector">vector</a>,
1035 <a href="#t_opaque">opaque</a>.
1036 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1037 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1038</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1039
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1040<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1041most important. Values of these types are the only ones which can be
1042produced by instructions, passed as arguments, or used as operands to
1043instructions. This means that all structures and arrays must be
1044manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1045</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1046
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1047<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1048<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1049
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1050<div class="doc_text">
1051<p>The primitive types are the fundamental building blocks of the LLVM
1052system.</p>
1053
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1054</div>
1055
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1056<!-- _______________________________________________________________________ -->
1057<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1058
1059<div class="doc_text">
1060 <table>
1061 <tbody>
1062 <tr><th>Type</th><th>Description</th></tr>
1063 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1064 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1065 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1066 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1067 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1068 </tbody>
1069 </table>
1070</div>
1071
1072<!-- _______________________________________________________________________ -->
1073<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1074
1075<div class="doc_text">
1076<h5>Overview:</h5>
1077<p>The void type does not represent any value and has no size.</p>
1078
1079<h5>Syntax:</h5>
1080
1081<pre>
1082 void
1083</pre>
1084</div>
1085
1086<!-- _______________________________________________________________________ -->
1087<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1088
1089<div class="doc_text">
1090<h5>Overview:</h5>
1091<p>The label type represents code labels.</p>
1092
1093<h5>Syntax:</h5>
1094
1095<pre>
1096 label
1097</pre>
1098</div>
1099
1100
1101<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1102<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1103
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1104<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1105
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1106<p>The real power in LLVM comes from the derived types in the system.
1107This is what allows a programmer to represent arrays, functions,
1108pointers, and other useful types. Note that these derived types may be
1109recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1110
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1111</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1112
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1113<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1114<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1115
1116<div class="doc_text">
1117
1118<h5>Overview:</h5>
1119<p>The integer type is a very simple derived type that simply specifies an
1120arbitrary bit width for the integer type desired. Any bit width from 1 bit to
11212^23-1 (about 8 million) can be specified.</p>
1122
1123<h5>Syntax:</h5>
1124
1125<pre>
1126 iN
1127</pre>
1128
1129<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1130value.</p>
1131
1132<h5>Examples:</h5>
1133<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1134 <tbody>
1135 <tr>
1136 <td><tt>i1</tt></td>
1137 <td>a single-bit integer.</td>
1138 </tr><tr>
1139 <td><tt>i32</tt></td>
1140 <td>a 32-bit integer.</td>
1141 </tr><tr>
1142 <td><tt>i1942652</tt></td>
1143 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1144 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +0000[diff] [blame]1145 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1146</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1147</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1148
1149<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1150<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1151
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1152<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1153
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1154<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1155
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1156<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1157sequentially in memory. The array type requires a size (number of
1158elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1159
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1160<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1161
1162<pre>
1163 [&lt;# elements&gt; x &lt;elementtype&gt;]
1164</pre>
1165
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1166<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1167be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1168
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1169<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1170<table class="layout">
1171 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1172 <td class="left"><tt>[40 x i32]</tt></td>
1173 <td class="left">Array of 40 32-bit integer values.</td>
1174 </tr>
1175 <tr class="layout">
1176 <td class="left"><tt>[41 x i32]</tt></td>
1177 <td class="left">Array of 41 32-bit integer values.</td>
1178 </tr>
1179 <tr class="layout">
1180 <td class="left"><tt>[4 x i8]</tt></td>
1181 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1182 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1183</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1184<p>Here are some examples of multidimensional arrays:</p>
1185<table class="layout">
1186 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1187 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1188 <td class="left">3x4 array of 32-bit integer values.</td>
1189 </tr>
1190 <tr class="layout">
1191 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1192 <td class="left">12x10 array of single precision floating point values.</td>
1193 </tr>
1194 <tr class="layout">
1195 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1196 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1197 </tr>
1198</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1199
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1200<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1201length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1202LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1203As a special case, however, zero length arrays are recognized to be variable
1204length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1205type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1206
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1207</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1208
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1209<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1210<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1211<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1212<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1213<p>The function type can be thought of as a function signature. It
1214consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1215Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1216(which are structures of pointers to functions), for indirect function
1217calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1218<p>
1219The return type of a function type cannot be an aggregate type.
1220</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1221<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1222<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1223<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]1224specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1225which indicates that the function takes a variable number of arguments.
1226Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1227 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1228<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1229<table class="layout">
1230 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1231 <td class="left"><tt>i32 (i32)</tt></td>
1232 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1233 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1234 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1235 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1236 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1237 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1238 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1239 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1240 <tt>float</tt>.
1241 </td>
1242 </tr><tr class="layout">
1243 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1244 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1245 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1246 which returns an integer. This is the signature for <tt>printf</tt> in
1247 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1248 </td>
1249 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1250</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1251
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1252</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1253<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1254<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1255<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1256<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1257<p>The structure type is used to represent a collection of data members
1258together in memory. The packing of the field types is defined to match
1259the ABI of the underlying processor. The elements of a structure may
1260be any type that has a size.</p>
1261<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1262and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1263field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1264instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1265<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1266<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1267<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1268<table class="layout">
1269 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1270 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1271 <td class="left">A triple of three <tt>i32</tt> values</td>
1272 </tr><tr class="layout">
1273 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1274 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1275 second element is a <a href="#t_pointer">pointer</a> to a
1276 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1277 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1278 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1279</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1280</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1281
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1282<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1283<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1284</div>
1285<div class="doc_text">
1286<h5>Overview:</h5>
1287<p>The packed structure type is used to represent a collection of data members
1288together in memory. There is no padding between fields. Further, the alignment
1289of a packed structure is 1 byte. The elements of a packed structure may
1290be any type that has a size.</p>
1291<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1292and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1293field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1294instruction.</p>
1295<h5>Syntax:</h5>
1296<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1297<h5>Examples:</h5>
1298<table class="layout">
1299 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1300 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1301 <td class="left">A triple of three <tt>i32</tt> values</td>
1302 </tr><tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1303 <td class="left"><tt>&lt; { float, i32 (i32)* } &gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1304 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1305 second element is a <a href="#t_pointer">pointer</a> to a
1306 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1307 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1308 </tr>
1309</table>
1310</div>
1311
1312<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1313<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1314<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1315<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1316<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]1317reference to another object, which must live in memory. Pointer types may have
1318an optional address space attribute defining the target-specific numbered
1319address space where the pointed-to object resides. The default address space is
1320zero.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1321<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1322<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1323<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1324<table class="layout">
1325 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1326 <td class="left"><tt>[4x i32]*</tt></td>
1327 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1328 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1329 </tr>
1330 <tr class="layout">
1331 <td class="left"><tt>i32 (i32 *) *</tt></td>
1332 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1333 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1334 <tt>i32</tt>.</td>
1335 </tr>
1336 <tr class="layout">
1337 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1338 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1339 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1340 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1341</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1342</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1343
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1344<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1345<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1346<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1347
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1348<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1349
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1350<p>A vector type is a simple derived type that represents a vector
1351of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1352are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1353A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1354elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1355of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1356considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1357
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1358<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1359
1360<pre>
1361 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1362</pre>
1363
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1364<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1365be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1366
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1367<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1368
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1369<table class="layout">
1370 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1371 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1372 <td class="left">Vector of 4 32-bit integer values.</td>
1373 </tr>
1374 <tr class="layout">
1375 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1376 <td class="left">Vector of 8 32-bit floating-point values.</td>
1377 </tr>
1378 <tr class="layout">
1379 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1380 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1381 </tr>
1382</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1383</div>
1384
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1385<!-- _______________________________________________________________________ -->
1386<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1387<div class="doc_text">
1388
1389<h5>Overview:</h5>
1390
1391<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +0000[diff] [blame]1392corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1393In LLVM, opaque types can eventually be resolved to any type (not just a
1394structure type).</p>
1395
1396<h5>Syntax:</h5>
1397
1398<pre>
1399 opaque
1400</pre>
1401
1402<h5>Examples:</h5>
1403
1404<table class="layout">
1405 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1406 <td class="left"><tt>opaque</tt></td>
1407 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1408 </tr>
1409</table>
1410</div>
1411
1412
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1413<!-- *********************************************************************** -->
1414<div class="doc_section"> <a name="constants">Constants</a> </div>
1415<!-- *********************************************************************** -->
1416
1417<div class="doc_text">
1418
1419<p>LLVM has several different basic types of constants. This section describes
1420them all and their syntax.</p>
1421
1422</div>
1423
1424<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1425<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1426
1427<div class="doc_text">
1428
1429<dl>
1430 <dt><b>Boolean constants</b></dt>
1431
1432 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1433 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1434 </dd>
1435
1436 <dt><b>Integer constants</b></dt>
1437
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1438 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1439 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1440 integer types.
1441 </dd>
1442
1443 <dt><b>Floating point constants</b></dt>
1444
1445 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1446 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1447 notation (see below). Floating point constants must have a <a
1448 href="#t_floating">floating point</a> type. </dd>
1449
1450 <dt><b>Null pointer constants</b></dt>
1451
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1452 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1453 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1454
1455</dl>
1456
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1457<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1458of floating point constants. For example, the form '<tt>double
14590x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
14604.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1461(and the only time that they are generated by the disassembler) is when a
1462floating point constant must be emitted but it cannot be represented as a
1463decimal floating point number. For example, NaN's, infinities, and other
1464special values are represented in their IEEE hexadecimal format so that
1465assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1466
1467</div>
1468
1469<!-- ======================================================================= -->
1470<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1471</div>
1472
1473<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1474<p>Aggregate constants arise from aggregation of simple constants
1475and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1476
1477<dl>
1478 <dt><b>Structure constants</b></dt>
1479
1480 <dd>Structure constants are represented with notation similar to structure
1481 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +0000[diff] [blame]1482 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1483 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]1484 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1485 types of elements must match those specified by the type.
1486 </dd>
1487
1488 <dt><b>Array constants</b></dt>
1489
1490 <dd>Array constants are represented with notation similar to array type
1491 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1492 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1493 constants must have <a href="#t_array">array type</a>, and the number and
1494 types of elements must match those specified by the type.
1495 </dd>
1496
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1497 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1498
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1499 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1500 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1501 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]1502 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1503 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1504 match those specified by the type.
1505 </dd>
1506
1507 <dt><b>Zero initialization</b></dt>
1508
1509 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1510 value to zero of <em>any</em> type, including scalar and aggregate types.
1511 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]1512 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1513 initializers.
1514 </dd>
1515</dl>
1516
1517</div>
1518
1519<!-- ======================================================================= -->
1520<div class="doc_subsection">
1521 <a name="globalconstants">Global Variable and Function Addresses</a>
1522</div>
1523
1524<div class="doc_text">
1525
1526<p>The addresses of <a href="#globalvars">global variables</a> and <a
1527href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1528constants. These constants are explicitly referenced when the <a
1529href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1530href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1531file:</p>
1532
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1533<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1534<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1535@X = global i32 17
1536@Y = global i32 42
1537@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1538</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1539</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1540
1541</div>
1542
1543<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1544<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1545<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1546 <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]1547 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1548 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1549
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1550 <p>Undefined values indicate to the compiler that the program is well defined
1551 no matter what value is used, giving the compiler more freedom to optimize.
1552 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1553</div>
1554
1555<!-- ======================================================================= -->
1556<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1557</div>
1558
1559<div class="doc_text">
1560
1561<p>Constant expressions are used to allow expressions involving other constants
1562to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1563href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1564that does not have side effects (e.g. load and call are not supported). The
1565following is the syntax for constant expressions:</p>
1566
1567<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1568 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1569 <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]1570 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1571
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1572 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1573 <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]1574 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]1575
1576 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1577 <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]1578 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]1579
1580 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1581 <dd>Truncate a floating point constant to another floating point type. The
1582 size of CST must be larger than the size of TYPE. Both types must be
1583 floating point.</dd>
1584
1585 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1586 <dd>Floating point extend a constant to another type. The size of CST must be
1587 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1588
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]1589 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1590 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1591 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1592 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1593 of the same number of elements. If the value won't fit in the integer type,
1594 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1595
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1596 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1597 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1598 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1599 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1600 of the same number of elements. If the value won't fit in the integer type,
1601 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1602
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1603 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1604 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1605 constant. TYPE must be a scalar or vector floating point type. CST must be of
1606 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1607 of the same number of elements. If the value won't fit in the floating point
1608 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1609
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1610 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1611 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]1612 constant. TYPE must be a scalar or vector floating point type. CST must be of
1613 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1614 of the same number of elements. If the value won't fit in the floating point
1615 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1616
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1617 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1618 <dd>Convert a pointer typed constant to the corresponding integer constant
1619 TYPE must be an integer type. CST must be of pointer type. The CST value is
1620 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1621
1622 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1623 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1624 pointer type. CST must be of integer type. The CST value is zero extended,
1625 truncated, or unchanged to make it fit in a pointer size. This one is
1626 <i>really</i> dangerous!</dd>
1627
1628 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1629 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1630 identical (same number of bits). The conversion is done as if the CST value
1631 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]1632 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1633 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]1634 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1635 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1636
1637 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1638
1639 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1640 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1641 instruction, the index list may have zero or more indexes, which are required
1642 to make sense for the type of "CSTPTR".</dd>
1643
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1644 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1645
1646 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1647 constants.</dd>
1648
1649 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1650 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1651
1652 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1653 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1654
1655 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1656
1657 <dd>Perform the <a href="#i_extractelement">extractelement
1658 operation</a> on constants.
1659
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1660 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1661
1662 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1663 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1664
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1665
1666 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1667
1668 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1669 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1670
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1671 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1672
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1673 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1674 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1675 binary</a> operations. The constraints on operands are the same as those for
1676 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1677 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1678</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1679</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1680
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1681<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1682<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1683<!-- *********************************************************************** -->
1684
1685<!-- ======================================================================= -->
1686<div class="doc_subsection">
1687<a name="inlineasm">Inline Assembler Expressions</a>
1688</div>
1689
1690<div class="doc_text">
1691
1692<p>
1693LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1694Module-Level Inline Assembly</a>) through the use of a special value. This
1695value represents the inline assembler as a string (containing the instructions
1696to emit), a list of operand constraints (stored as a string), and a flag that
1697indicates whether or not the inline asm expression has side effects. An example
1698inline assembler expression is:
1699</p>
1700
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1701<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1702<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1703i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1704</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1705</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1706
1707<p>
1708Inline assembler expressions may <b>only</b> be used as the callee operand of
1709a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1710</p>
1711
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1712<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1713<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1714%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]1715</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1716</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1717
1718<p>
1719Inline asms with side effects not visible in the constraint list must be marked
1720as having side effects. This is done through the use of the
1721'<tt>sideeffect</tt>' keyword, like so:
1722</p>
1723
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1724<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1725<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1726call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1727</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1728</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1729
1730<p>TODO: The format of the asm and constraints string still need to be
1731documented here. Constraints on what can be done (e.g. duplication, moving, etc
1732need to be documented).
1733</p>
1734
1735</div>
1736
1737<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1738<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1739<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1740
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1741<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1742
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1743<p>The LLVM instruction set consists of several different
1744classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1745instructions</a>, <a href="#binaryops">binary instructions</a>,
1746<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1747 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1748instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1749
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1750</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1751
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1753<div class="doc_subsection"> <a name="terminators">Terminator
1754Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1755
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1756<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1757
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1758<p>As mentioned <a href="#functionstructure">previously</a>, every
1759basic block in a program ends with a "Terminator" instruction, which
1760indicates which block should be executed after the current block is
1761finished. These terminator instructions typically yield a '<tt>void</tt>'
1762value: they produce control flow, not values (the one exception being
1763the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1764<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1765 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1766instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1767the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1768 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1769 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1770
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1771</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1772
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1773<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1774<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1775Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1776<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1777<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1778<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]1779 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1780</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1781<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1782<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1783value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1784<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1785returns a value and then causes control flow, and one that just causes
1786control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1787<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1788<p>The '<tt>ret</tt>' instruction may return any '<a
1789 href="#t_firstclass">first class</a>' type. Notice that a function is
1790not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1791instruction inside of the function that returns a value that does not
1792match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1793<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1794<p>When the '<tt>ret</tt>' instruction is executed, control flow
1795returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1796 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1797the instruction after the call. If the caller was an "<a
1798 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1799at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1800returns a value, that value shall set the call or invoke instruction's
1801return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1802<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1803<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1804 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1805</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1806</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1807<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1808<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1809<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1810<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1811<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]1812</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1813<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1814<p>The '<tt>br</tt>' instruction is used to cause control flow to
1815transfer to a different basic block in the current function. There are
1816two forms of this instruction, corresponding to a conditional branch
1817and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1818<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1819<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1820single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1821unconditional form of the '<tt>br</tt>' instruction takes a single
1822'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1823<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1824<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1825argument is evaluated. If the value is <tt>true</tt>, control flows
1826to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1827control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1828<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1829<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]1830 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]1831</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1832<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1833<div class="doc_subsubsection">
1834 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1835</div>
1836
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1837<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1838<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1839
1840<pre>
1841 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1842</pre>
1843
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1844<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1845
1846<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1847several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1848instruction, allowing a branch to occur to one of many possible
1849destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1850
1851
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1852<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1853
1854<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1855comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1856an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1857table is not allowed to contain duplicate constant entries.</p>
1858
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1859<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1860
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1861<p>The <tt>switch</tt> instruction specifies a table of values and
1862destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1863table is searched for the given value. If the value is found, control flow is
1864transfered to the corresponding destination; otherwise, control flow is
1865transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1866
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1867<h5>Implementation:</h5>
1868
1869<p>Depending on properties of the target machine and the particular
1870<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1871ways. For example, it could be generated as a series of chained conditional
1872branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1873
1874<h5>Example:</h5>
1875
1876<pre>
1877 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1878 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1879 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1880
1881 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1882 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1883
1884 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1885 switch i32 %val, label %otherwise [ i32 0, label %onzero
1886 i32 1, label %onone
1887 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1888</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1889</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1890
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1891<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1892<div class="doc_subsubsection">
1893 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1894</div>
1895
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1896<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1897
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1898<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1899
1900<pre>
1901 &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]1902 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1903</pre>
1904
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1905<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1906
1907<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1908function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1909'<tt>normal</tt>' label or the
1910'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1911"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1912"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1913href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1914continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1916<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1917
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1918<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1919
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1920<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1921 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1922 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1923 convention</a> the call should use. If none is specified, the call defaults
1924 to using C calling conventions.
1925 </li>
1926 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1927 function value being invoked. In most cases, this is a direct function
1928 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1929 an arbitrary pointer to function value.
1930 </li>
1931
1932 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1933 function to be invoked. </li>
1934
1935 <li>'<tt>function args</tt>': argument list whose types match the function
1936 signature argument types. If the function signature indicates the function
1937 accepts a variable number of arguments, the extra arguments can be
1938 specified. </li>
1939
1940 <li>'<tt>normal label</tt>': the label reached when the called function
1941 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1942
1943 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1944 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1945
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1946</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1947
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1948<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1949
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1950<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1951href="#i_call">call</a></tt>' instruction in most regards. The primary
1952difference is that it establishes an association with a label, which is used by
1953the runtime library to unwind the stack.</p>
1954
1955<p>This instruction is used in languages with destructors to ensure that proper
1956cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1957exception. Additionally, this is important for implementation of
1958'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1959
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1960<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1961<pre>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1962 %retval = invoke i32 %Test(i32 15) to label %Continue
1963 unwind label %TestCleanup <i>; {i32}:retval set</i>
1964 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1965 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1966</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1967</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1968
1969
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1970<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1971
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1972<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1973Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1974
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1975<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1976
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1977<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1978<pre>
1979 unwind
1980</pre>
1981
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1982<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1983
1984<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1985at the first callee in the dynamic call stack which used an <a
1986href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1987primarily used to implement exception handling.</p>
1988
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1989<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1990
1991<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1992immediately halt. The dynamic call stack is then searched for the first <a
1993href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1994execution continues at the "exceptional" destination block specified by the
1995<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1996dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1997</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1998
1999<!-- _______________________________________________________________________ -->
2000
2001<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2002Instruction</a> </div>
2003
2004<div class="doc_text">
2005
2006<h5>Syntax:</h5>
2007<pre>
2008 unreachable
2009</pre>
2010
2011<h5>Overview:</h5>
2012
2013<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2014instruction is used to inform the optimizer that a particular portion of the
2015code is not reachable. This can be used to indicate that the code after a
2016no-return function cannot be reached, and other facts.</p>
2017
2018<h5>Semantics:</h5>
2019
2020<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2021</div>
2022
2023
2024
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2025<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2026<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2027<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2028<p>Binary operators are used to do most of the computation in a
2029program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2030produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2031multiple 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]2032The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2033necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2034<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2035</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2036<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2037<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
2038Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2039<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2040<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2041<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]2042</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2043<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2044<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2045<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2046<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2047 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2048 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]2049Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2050<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2051<p>The value produced is the integer or floating point sum of the two
2052operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2053<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2054<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]2055</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2056</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2057<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2058<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
2059Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2060<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2061<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2062<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]2063</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2064<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2065<p>The '<tt>sub</tt>' instruction returns the difference of its two
2066operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2067<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
2068instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2069<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2070<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2071 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2072values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2073This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2074Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2076<p>The value produced is the integer or floating point difference of
2077the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2078<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2079<pre>
2080 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2081 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2082</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2083</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2084<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2085<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
2086Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2087<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2088<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2089<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]2090</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2091<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2092<p>The '<tt>mul</tt>' instruction returns the product of its two
2093operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2094<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2095<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2096 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2097values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2098This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2099Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2100<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2101<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2102two operands.</p>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]2103<p>Because the operands are the same width, the result of an integer
2104multiplication is the same whether the operands should be deemed unsigned or
2105signed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2106<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2107<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]2108</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2109</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2110<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2111<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2112</a></div>
2113<div class="doc_text">
2114<h5>Syntax:</h5>
2115<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2116</pre>
2117<h5>Overview:</h5>
2118<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2119operands.</p>
2120<h5>Arguments:</h5>
2121<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2122<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2123types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2124of the values in which case the elements must be integers.</p>
2125<h5>Semantics:</h5>
2126<p>The value produced is the unsigned integer quotient of the two operands. This
2127instruction always performs an unsigned division operation, regardless of
2128whether the arguments are unsigned or not.</p>
2129<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2130<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]2131</pre>
2132</div>
2133<!-- _______________________________________________________________________ -->
2134<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2135</a> </div>
2136<div class="doc_text">
2137<h5>Syntax:</h5>
2138<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2139</pre>
2140<h5>Overview:</h5>
2141<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2142operands.</p>
2143<h5>Arguments:</h5>
2144<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2145<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2146types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2147of the values in which case the elements must be integers.</p>
2148<h5>Semantics:</h5>
2149<p>The value produced is the signed integer quotient of the two operands. This
2150instruction always performs a signed division operation, regardless of whether
2151the arguments are signed or not.</p>
2152<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2153<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]2154</pre>
2155</div>
2156<!-- _______________________________________________________________________ -->
2157<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2158Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2159<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2160<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2161<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]2162</pre>
2163<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2164<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2165operands.</p>
2166<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2167<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2168<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2169identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2170versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2171<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2172<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2173<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2174<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]2175</pre>
2176</div>
2177<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2178<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2179</div>
2180<div class="doc_text">
2181<h5>Syntax:</h5>
2182<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2183</pre>
2184<h5>Overview:</h5>
2185<p>The '<tt>urem</tt>' instruction returns the remainder from the
2186unsigned division of its two arguments.</p>
2187<h5>Arguments:</h5>
2188<p>The two arguments to the '<tt>urem</tt>' instruction must be
2189<a href="#t_integer">integer</a> values. Both arguments must have identical
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2190types. This instruction can also take <a href="#t_vector">vector</a> versions
2191of the values in which case the elements must be integers.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2192<h5>Semantics:</h5>
2193<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2194This instruction always performs an unsigned division to get the remainder,
2195regardless of whether the arguments are unsigned or not.</p>
2196<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2197<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]2198</pre>
2199
2200</div>
2201<!-- _______________________________________________________________________ -->
2202<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2203Instruction</a> </div>
2204<div class="doc_text">
2205<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2206<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]2207</pre>
2208<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2209<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2210signed division of its two operands. This instruction can also take
2211<a href="#t_vector">vector</a> versions of the values in which case
2212the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]2213
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2214<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2215<p>The two arguments to the '<tt>srem</tt>' instruction must be
2216<a href="#t_integer">integer</a> values. Both arguments must have identical
2217types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2218<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2219<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2220has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2221operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2222a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2223 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2224Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2225please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2226Wikipedia: modulo operation</a>.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2227<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2228<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]2229</pre>
2230
2231</div>
2232<!-- _______________________________________________________________________ -->
2233<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2234Instruction</a> </div>
2235<div class="doc_text">
2236<h5>Syntax:</h5>
2237<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2238</pre>
2239<h5>Overview:</h5>
2240<p>The '<tt>frem</tt>' instruction returns the remainder from the
2241division of its two operands.</p>
2242<h5>Arguments:</h5>
2243<p>The two arguments to the '<tt>frem</tt>' instruction must be
2244<a href="#t_floating">floating point</a> values. Both arguments must have
Dan Gohman08143e32007-11-05 23:35:22 +0000[diff] [blame]2245identical types. This instruction can also take <a href="#t_vector">vector</a>
2246versions of floating point values.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2247<h5>Semantics:</h5>
2248<p>This instruction returns the <i>remainder</i> of a division.</p>
2249<h5>Example:</h5>
2250<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]2251</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2252</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2253
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2254<!-- ======================================================================= -->
2255<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2256Operations</a> </div>
2257<div class="doc_text">
2258<p>Bitwise binary operators are used to do various forms of
2259bit-twiddling in a program. They are generally very efficient
2260instructions and can commonly be strength reduced from other
2261instructions. They require two operands, execute an operation on them,
2262and produce a single value. The resulting value of the bitwise binary
2263operators is always the same type as its first operand.</p>
2264</div>
2265
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2266<!-- _______________________________________________________________________ -->
2267<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2268Instruction</a> </div>
2269<div class="doc_text">
2270<h5>Syntax:</h5>
2271<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2272</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2273
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2274<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2275
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2276<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2277the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2278
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2279<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2280
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2281<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2282 href="#t_integer">integer</a> type.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2283
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2284<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2285
2286<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>. If
2287<tt>var2</tt> is (statically or dynamically) equal to or larger than the number
2288of bits in <tt>var1</tt>, the result is undefined.</p>
2289
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2290<h5>Example:</h5><pre>
2291 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2292 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2293 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2294 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2295</pre>
2296</div>
2297<!-- _______________________________________________________________________ -->
2298<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2299Instruction</a> </div>
2300<div class="doc_text">
2301<h5>Syntax:</h5>
2302<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2303</pre>
2304
2305<h5>Overview:</h5>
2306<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2307operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2308
2309<h5>Arguments:</h5>
2310<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2311<a href="#t_integer">integer</a> type.</p>
2312
2313<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2314
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2315<p>This instruction always performs a logical shift right operation. The most
2316significant bits of the result will be filled with zero bits after the
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2317shift. If <tt>var2</tt> is (statically or dynamically) equal to or larger than
2318the number of bits in <tt>var1</tt>, the result is undefined.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2319
2320<h5>Example:</h5>
2321<pre>
2322 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2323 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2324 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2325 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2326 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2327</pre>
2328</div>
2329
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2330<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2331<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2332Instruction</a> </div>
2333<div class="doc_text">
2334
2335<h5>Syntax:</h5>
2336<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2337</pre>
2338
2339<h5>Overview:</h5>
2340<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2341operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2342
2343<h5>Arguments:</h5>
2344<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2345<a href="#t_integer">integer</a> type.</p>
2346
2347<h5>Semantics:</h5>
2348<p>This instruction always performs an arithmetic shift right operation,
2349The most significant bits of the result will be filled with the sign bit
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2350of <tt>var1</tt>. If <tt>var2</tt> is (statically or dynamically) equal to or
2351larger than the number of bits in <tt>var1</tt>, the result is undefined.
2352</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2353
2354<h5>Example:</h5>
2355<pre>
2356 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2357 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2358 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2359 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]2360 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2361</pre>
2362</div>
2363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2364<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2365<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2366Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2367<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2368<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2369<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]2370</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2371<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2372<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2373its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2374<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2375<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2376 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2377identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2378<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2379<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2380<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2381<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2382<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2383 <tbody>
2384 <tr>
2385 <td>In0</td>
2386 <td>In1</td>
2387 <td>Out</td>
2388 </tr>
2389 <tr>
2390 <td>0</td>
2391 <td>0</td>
2392 <td>0</td>
2393 </tr>
2394 <tr>
2395 <td>0</td>
2396 <td>1</td>
2397 <td>0</td>
2398 </tr>
2399 <tr>
2400 <td>1</td>
2401 <td>0</td>
2402 <td>0</td>
2403 </tr>
2404 <tr>
2405 <td>1</td>
2406 <td>1</td>
2407 <td>1</td>
2408 </tr>
2409 </tbody>
2410</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2411</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2412<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2413<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2414 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2415 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2416</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2417</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2418<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2419<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2420<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2421<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2422<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]2423</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2424<h5>Overview:</h5>
2425<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2426or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2427<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2428<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2429 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2430identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2431<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2432<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2433<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2434<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2435<table border="1" cellspacing="0" cellpadding="4">
2436 <tbody>
2437 <tr>
2438 <td>In0</td>
2439 <td>In1</td>
2440 <td>Out</td>
2441 </tr>
2442 <tr>
2443 <td>0</td>
2444 <td>0</td>
2445 <td>0</td>
2446 </tr>
2447 <tr>
2448 <td>0</td>
2449 <td>1</td>
2450 <td>1</td>
2451 </tr>
2452 <tr>
2453 <td>1</td>
2454 <td>0</td>
2455 <td>1</td>
2456 </tr>
2457 <tr>
2458 <td>1</td>
2459 <td>1</td>
2460 <td>1</td>
2461 </tr>
2462 </tbody>
2463</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2464</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2465<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2466<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2467 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2468 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2469</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2470</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2471<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2472<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2473Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2474<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2475<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2476<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]2477</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2478<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2479<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2480or of its two operands. The <tt>xor</tt> is used to implement the
2481"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2482<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2483<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2484 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2485identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2486<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2487<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2488<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2489<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2490<table border="1" cellspacing="0" cellpadding="4">
2491 <tbody>
2492 <tr>
2493 <td>In0</td>
2494 <td>In1</td>
2495 <td>Out</td>
2496 </tr>
2497 <tr>
2498 <td>0</td>
2499 <td>0</td>
2500 <td>0</td>
2501 </tr>
2502 <tr>
2503 <td>0</td>
2504 <td>1</td>
2505 <td>1</td>
2506 </tr>
2507 <tr>
2508 <td>1</td>
2509 <td>0</td>
2510 <td>1</td>
2511 </tr>
2512 <tr>
2513 <td>1</td>
2514 <td>1</td>
2515 <td>0</td>
2516 </tr>
2517 </tbody>
2518</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2519</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2520<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2521<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2522<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2523 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2524 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2525 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2526</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2527</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2528
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2529<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2530<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2531 <a name="vectorops">Vector Operations</a>
2532</div>
2533
2534<div class="doc_text">
2535
2536<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2537target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2538vector-specific operations needed to process vectors effectively. While LLVM
2539does directly support these vector operations, many sophisticated algorithms
2540will want to use target-specific intrinsics to take full advantage of a specific
2541target.</p>
2542
2543</div>
2544
2545<!-- _______________________________________________________________________ -->
2546<div class="doc_subsubsection">
2547 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2548</div>
2549
2550<div class="doc_text">
2551
2552<h5>Syntax:</h5>
2553
2554<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2555 &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]2556</pre>
2557
2558<h5>Overview:</h5>
2559
2560<p>
2561The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2562element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2563</p>
2564
2565
2566<h5>Arguments:</h5>
2567
2568<p>
2569The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2570value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2571an index indicating the position from which to extract the element.
2572The index may be a variable.</p>
2573
2574<h5>Semantics:</h5>
2575
2576<p>
2577The result is a scalar of the same type as the element type of
2578<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2579<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2580results are undefined.
2581</p>
2582
2583<h5>Example:</h5>
2584
2585<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2586 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2587</pre>
2588</div>
2589
2590
2591<!-- _______________________________________________________________________ -->
2592<div class="doc_subsubsection">
2593 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2594</div>
2595
2596<div class="doc_text">
2597
2598<h5>Syntax:</h5>
2599
2600<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2601 &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]2602</pre>
2603
2604<h5>Overview:</h5>
2605
2606<p>
2607The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2608element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2609</p>
2610
2611
2612<h5>Arguments:</h5>
2613
2614<p>
2615The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2616value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2617scalar value whose type must equal the element type of the first
2618operand. The third operand is an index indicating the position at
2619which to insert the value. The index may be a variable.</p>
2620
2621<h5>Semantics:</h5>
2622
2623<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2624The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2625element values are those of <tt>val</tt> except at position
2626<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2627exceeds the length of <tt>val</tt>, the results are undefined.
2628</p>
2629
2630<h5>Example:</h5>
2631
2632<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2633 %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]2634</pre>
2635</div>
2636
2637<!-- _______________________________________________________________________ -->
2638<div class="doc_subsubsection">
2639 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2640</div>
2641
2642<div class="doc_text">
2643
2644<h5>Syntax:</h5>
2645
2646<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2647 &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]2648</pre>
2649
2650<h5>Overview:</h5>
2651
2652<p>
2653The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2654from two input vectors, returning a vector of the same type.
2655</p>
2656
2657<h5>Arguments:</h5>
2658
2659<p>
2660The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2661with types that match each other and types that match the result of the
2662instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2663of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2664</p>
2665
2666<p>
2667The shuffle mask operand is required to be a constant vector with either
2668constant integer or undef values.
2669</p>
2670
2671<h5>Semantics:</h5>
2672
2673<p>
2674The elements of the two input vectors are numbered from left to right across
2675both of the vectors. The shuffle mask operand specifies, for each element of
2676the result vector, which element of the two input registers the result element
2677gets. The element selector may be undef (meaning "don't care") and the second
2678operand may be undef if performing a shuffle from only one vector.
2679</p>
2680
2681<h5>Example:</h5>
2682
2683<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2684 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2685 &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]2686 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2687 &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]2688</pre>
2689</div>
2690
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2691
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2692<!-- ======================================================================= -->
2693<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2694 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2695</div>
2696
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2697<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2698
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2699<p>A key design point of an SSA-based representation is how it
2700represents memory. In LLVM, no memory locations are in SSA form, which
2701makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2702allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2703
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2704</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2705
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2706<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2707<div class="doc_subsubsection">
2708 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2709</div>
2710
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2711<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2712
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2713<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2714
2715<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2716 &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]2717</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2718
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2719<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2720
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2721<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2722heap and returns a pointer to it. The object is always allocated in the generic
2723address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2724
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2725<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2726
2727<p>The '<tt>malloc</tt>' instruction allocates
2728<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2729bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2730appropriate type to the program. If "NumElements" is specified, it is the
2731number of elements allocated. If an alignment is specified, the value result
2732of the allocation is guaranteed to be aligned to at least that boundary. If
2733not specified, or if zero, the target can choose to align the allocation on any
2734convenient boundary.</p>
2735
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2736<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2737
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2738<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2739
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2740<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2741a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2742
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2743<h5>Example:</h5>
2744
2745<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2746 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2747
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2748 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2749 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2750 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2751 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2752 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2753</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2754</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2755
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2756<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2757<div class="doc_subsubsection">
2758 <a name="i_free">'<tt>free</tt>' Instruction</a>
2759</div>
2760
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2761<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2762
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2763<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2764
2765<pre>
2766 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2767</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2768
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2769<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2770
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2771<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2772memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2773
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2774<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2775
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2776<p>'<tt>value</tt>' shall be a pointer value that points to a value
2777that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2778instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2779
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2780<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2781
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2782<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2783after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2784
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2785<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2786
2787<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2788 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2789 free [4 x i8]* %array
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_alloca">'<tt>alloca</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>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2803 &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]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
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2808<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2809currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]2810returns to its caller. The object is always allocated in the generic address
2811space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2812
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2813<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2814
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2815<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2816bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2817appropriate type to the program. If "NumElements" is specified, it is the
2818number of elements allocated. If an alignment is specified, the value result
2819of the allocation is guaranteed to be aligned to at least that boundary. If
2820not specified, or if zero, the target can choose to align the allocation on any
2821convenient boundary.</p>
2822
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2823<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2824
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2825<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2826
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2827<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2828memory is automatically released when the function returns. The '<tt>alloca</tt>'
2829instruction is commonly used to represent automatic variables that must
2830have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2831 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]2832instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2834<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2835
2836<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2837 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2838 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2839 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2840 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2841</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2842</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2843
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2845<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2846Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2847<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2848<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2849<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]2850<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2851<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2852<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2853<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2854address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2855 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2856marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2857the number or order of execution of this <tt>load</tt> with other
2858volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2859instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +0000[diff] [blame]2860<p>
2861The optional "align" argument specifies the alignment of the operation
2862(that is, the alignment of the memory address). A value of 0 or an
2863omitted "align" argument means that the operation has the preferential
2864alignment for the target. It is the responsibility of the code emitter
2865to ensure that the alignment information is correct. Overestimating
2866the alignment results in an undefined behavior. Underestimating the
2867alignment may produce less efficient code. An alignment of 1 is always
2868safe.
2869</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2870<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2871<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2872<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2873<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2874 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2875 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2876 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2877</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2878</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2879<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2880<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2881Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2882<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2883<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2884<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2885 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]2886</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>store</tt>' instruction is used to write to 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>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2891to 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]2892operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2893operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2894optimizer is not allowed to modify the number or order of execution of
2895this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2896 href="#i_store">store</a></tt> instructions.</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 Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2907<h5>Semantics:</h5>
2908<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2909at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2910<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2911<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]2912 store i32 3, i32* %ptr <i>; yields {void}</i>
2913 %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]2914</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2915</div>
2916
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2917<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2918<div class="doc_subsubsection">
2919 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2920</div>
2921
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2922<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2923<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2924<pre>
2925 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2926</pre>
2927
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2928<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2929
2930<p>
2931The '<tt>getelementptr</tt>' instruction is used to get the address of a
2932subelement of an aggregate data structure.</p>
2933
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2934<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2935
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2936<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2937elements of the aggregate object to index to. The actual types of the arguments
2938provided depend on the type of the first pointer argument. The
2939'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2940levels 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]2941structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2942into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2943be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2944
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2945<p>For example, let's consider a C code fragment and how it gets
2946compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2947
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2948<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2949<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2950struct RT {
2951 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2952 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2953 char C;
2954};
2955struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2956 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2957 double Y;
2958 struct RT Z;
2959};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2960
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2961int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2962 return &amp;s[1].Z.B[5][13];
2963}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2964</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2965</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2966
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2967<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2968
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2969<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2970<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2971%RT = type { i8 , [10 x [20 x i32]], i8 }
2972%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2973
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2974define i32* %foo(%ST* %s) {
2975entry:
2976 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2977 ret i32* %reg
2978}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2979</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2980</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2981
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2982<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2983
2984<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2985on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2986and <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]2987<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]2988to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2989<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2990
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2991<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]2992type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2993}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2994the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2995i8 }</tt>' type, another structure. The third index indexes into the second
2996element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2997array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2998'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2999to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3000
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3001<p>Note that it is perfectly legal to index partially through a
3002structure, returning a pointer to an inner element. Because of this,
3003the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3004
3005<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3006 define i32* %foo(%ST* %s) {
3007 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3008 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3009 %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]3010 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3011 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3012 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3013 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3014</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3015
3016<p>Note that it is undefined to access an array out of bounds: array and
3017pointer indexes must always be within the defined bounds of the array type.
3018The one exception for this rules is zero length arrays. These arrays are
3019defined to be accessible as variable length arrays, which requires access
3020beyond the zero'th element.</p>
3021
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]3022<p>The getelementptr instruction is often confusing. For some more insight
3023into how it works, see <a href="GetElementPtr.html">the getelementptr
3024FAQ</a>.</p>
3025
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3026<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]3027
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3028<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3029 <i>; yields [12 x i8]*:aptr</i>
3030 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3031</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]3032</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]3033
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3034<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3035<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3036</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3037<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3038<p>The instructions in this category are the conversion instructions (casting)
3039which all take a single operand and a type. They perform various bit conversions
3040on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3041</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3042
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3043<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3044<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3045 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3046</div>
3047<div class="doc_text">
3048
3049<h5>Syntax:</h5>
3050<pre>
3051 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3052</pre>
3053
3054<h5>Overview:</h5>
3055<p>
3056The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3057</p>
3058
3059<h5>Arguments:</h5>
3060<p>
3061The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3062be 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]3063and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3064type. The bit size of <tt>value</tt> must be larger than the bit size of
3065<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3066
3067<h5>Semantics:</h5>
3068<p>
3069The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3070and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3071larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3072It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3073
3074<h5>Example:</h5>
3075<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3076 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3077 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3078 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3079</pre>
3080</div>
3081
3082<!-- _______________________________________________________________________ -->
3083<div class="doc_subsubsection">
3084 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3085</div>
3086<div class="doc_text">
3087
3088<h5>Syntax:</h5>
3089<pre>
3090 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3091</pre>
3092
3093<h5>Overview:</h5>
3094<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3095<tt>ty2</tt>.</p>
3096
3097
3098<h5>Arguments:</h5>
3099<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]3100<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3101also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3102<tt>value</tt> must be smaller than the bit size of the destination type,
3103<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3104
3105<h5>Semantics:</h5>
3106<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]3107bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3108
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]3109<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]3110
3111<h5>Example:</h5>
3112<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3113 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3114 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3115</pre>
3116</div>
3117
3118<!-- _______________________________________________________________________ -->
3119<div class="doc_subsubsection">
3120 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3121</div>
3122<div class="doc_text">
3123
3124<h5>Syntax:</h5>
3125<pre>
3126 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3127</pre>
3128
3129<h5>Overview:</h5>
3130<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3131
3132<h5>Arguments:</h5>
3133<p>
3134The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3135<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3136also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3137<tt>value</tt> must be smaller than the bit size of the destination type,
3138<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3139
3140<h5>Semantics:</h5>
3141<p>
3142The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3143bit (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]3144the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3145
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3146<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]3147
3148<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3149<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3150 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3151 %Y = sext 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">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3157 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3158</div>
3159
3160<div class="doc_text">
3161
3162<h5>Syntax:</h5>
3163
3164<pre>
3165 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3166</pre>
3167
3168<h5>Overview:</h5>
3169<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3170<tt>ty2</tt>.</p>
3171
3172
3173<h5>Arguments:</h5>
3174<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3175 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3176cast it to. The size of <tt>value</tt> must be larger than the size of
3177<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3178<i>no-op cast</i>.</p>
3179
3180<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3181<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3182<a href="#t_floating">floating point</a> type to a smaller
3183<a href="#t_floating">floating point</a> type. If the value cannot fit within
3184the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3185
3186<h5>Example:</h5>
3187<pre>
3188 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3189 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3190</pre>
3191</div>
3192
3193<!-- _______________________________________________________________________ -->
3194<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3195 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3196</div>
3197<div class="doc_text">
3198
3199<h5>Syntax:</h5>
3200<pre>
3201 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3202</pre>
3203
3204<h5>Overview:</h5>
3205<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3206floating point value.</p>
3207
3208<h5>Arguments:</h5>
3209<p>The '<tt>fpext</tt>' instruction takes a
3210<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3211and a <a href="#t_floating">floating point</a> type to cast it to. The source
3212type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3213
3214<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3215<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3216<a href="#t_floating">floating point</a> type to a larger
3217<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3218used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3219<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]3220
3221<h5>Example:</h5>
3222<pre>
3223 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3224 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3225</pre>
3226</div>
3227
3228<!-- _______________________________________________________________________ -->
3229<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3230 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3231</div>
3232<div class="doc_text">
3233
3234<h5>Syntax:</h5>
3235<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3236 &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]3237</pre>
3238
3239<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3240<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3241unsigned integer equivalent of type <tt>ty2</tt>.
3242</p>
3243
3244<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3245<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]3246scalar or vector <a href="#t_floating">floating point</a> value, and a type
3247to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3248type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3249vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3250
3251<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3252<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3253<a href="#t_floating">floating point</a> operand into the nearest (rounding
3254towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3255the results are undefined.</p>
3256
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3257<h5>Example:</h5>
3258<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3259 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3260 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]3261 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3262</pre>
3263</div>
3264
3265<!-- _______________________________________________________________________ -->
3266<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3267 <a name="i_fptosi">'<tt>fptosi .. 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 Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3273 &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]3274</pre>
3275
3276<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3277<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3278<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]3279</p>
3280
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3281<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3282<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]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>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3287
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3288<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3289<p>The '<tt>fptosi</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) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3292the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3293
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3294<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3295<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3296 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]3297 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3298 %X = fptosi 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_uitofp">'<tt>uitofp .. 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; = 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]3311</pre>
3312
3313<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3314<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3315integer and converts that value to the <tt>ty2</tt> type.</p>
3316
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3317<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3318<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3319scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3320to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3321type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3322floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3323
3324<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3325<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3326integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3327the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3328
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3329<h5>Example:</h5>
3330<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3331 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3332 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3333</pre>
3334</div>
3335
3336<!-- _______________________________________________________________________ -->
3337<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3338 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3339</div>
3340<div class="doc_text">
3341
3342<h5>Syntax:</h5>
3343<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3344 &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]3345</pre>
3346
3347<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3348<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3349integer and converts that value to the <tt>ty2</tt> type.</p>
3350
3351<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]3352<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3353scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3354to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3355type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3356floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3357
3358<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3359<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3360integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3361the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3362
3363<h5>Example:</h5>
3364<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3365 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3366 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3367</pre>
3368</div>
3369
3370<!-- _______________________________________________________________________ -->
3371<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3372 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3373</div>
3374<div class="doc_text">
3375
3376<h5>Syntax:</h5>
3377<pre>
3378 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3379</pre>
3380
3381<h5>Overview:</h5>
3382<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3383the integer type <tt>ty2</tt>.</p>
3384
3385<h5>Arguments:</h5>
3386<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3387must 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]3388<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3389
3390<h5>Semantics:</h5>
3391<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3392<tt>ty2</tt> by interpreting the pointer value as an integer and either
3393truncating or zero extending that value to the size of the integer type. If
3394<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3395<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]3396are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3397change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3398
3399<h5>Example:</h5>
3400<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3401 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3402 %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]3403</pre>
3404</div>
3405
3406<!-- _______________________________________________________________________ -->
3407<div class="doc_subsubsection">
3408 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3409</div>
3410<div class="doc_text">
3411
3412<h5>Syntax:</h5>
3413<pre>
3414 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3415</pre>
3416
3417<h5>Overview:</h5>
3418<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3419a pointer type, <tt>ty2</tt>.</p>
3420
3421<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3422<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3423value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3424<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3425
3426<h5>Semantics:</h5>
3427<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3428<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3429the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3430size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3431the size of a pointer then a zero extension is done. If they are the same size,
3432nothing is done (<i>no-op cast</i>).</p>
3433
3434<h5>Example:</h5>
3435<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3436 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3437 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3438 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3439</pre>
3440</div>
3441
3442<!-- _______________________________________________________________________ -->
3443<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3444 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3445</div>
3446<div class="doc_text">
3447
3448<h5>Syntax:</h5>
3449<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3450 &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]3451</pre>
3452
3453<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3454<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3455<tt>ty2</tt> without changing any bits.</p>
3456
3457<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3458<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3459a first class value, and a type to cast it to, which must also be a <a
3460 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3461and the destination type, <tt>ty2</tt>, must be identical. If the source
3462type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3463
3464<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3465<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3466<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3467this conversion. The conversion is done as if the <tt>value</tt> had been
3468stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3469converted to other pointer types with this instruction. To convert pointers to
3470other types, use the <a href="#i_inttoptr">inttoptr</a> or
3471<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3472
3473<h5>Example:</h5>
3474<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3475 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3476 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3477 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3478</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3479</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3480
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3481<!-- ======================================================================= -->
3482<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3483<div class="doc_text">
3484<p>The instructions in this category are the "miscellaneous"
3485instructions, which defy better classification.</p>
3486</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3487
3488<!-- _______________________________________________________________________ -->
3489<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3490</div>
3491<div class="doc_text">
3492<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3493<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]3494</pre>
3495<h5>Overview:</h5>
3496<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3497of its two integer operands.</p>
3498<h5>Arguments:</h5>
3499<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3500the condition code indicating the kind of comparison to perform. It is not
3501a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3502<ol>
3503 <li><tt>eq</tt>: equal</li>
3504 <li><tt>ne</tt>: not equal </li>
3505 <li><tt>ugt</tt>: unsigned greater than</li>
3506 <li><tt>uge</tt>: unsigned greater or equal</li>
3507 <li><tt>ult</tt>: unsigned less than</li>
3508 <li><tt>ule</tt>: unsigned less or equal</li>
3509 <li><tt>sgt</tt>: signed greater than</li>
3510 <li><tt>sge</tt>: signed greater or equal</li>
3511 <li><tt>slt</tt>: signed less than</li>
3512 <li><tt>sle</tt>: signed less or equal</li>
3513</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3514<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3515<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3516<h5>Semantics:</h5>
3517<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3518the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3519yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3520<ol>
3521 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3522 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3523 </li>
3524 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3525 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3526 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3527 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3528 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3529 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3530 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3531 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3532 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3533 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3534 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3535 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3536 <li><tt>sge</tt>: interprets the operands as signed values and yields
3537 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3538 <li><tt>slt</tt>: interprets the operands as signed values and yields
3539 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3540 <li><tt>sle</tt>: interprets the operands as signed values and yields
3541 <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]3542</ol>
3543<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3544values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3545
3546<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3547<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3548 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3549 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3550 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3551 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3552 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3553</pre>
3554</div>
3555
3556<!-- _______________________________________________________________________ -->
3557<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3558</div>
3559<div class="doc_text">
3560<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3561<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]3562</pre>
3563<h5>Overview:</h5>
3564<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3565of its floating point operands.</p>
3566<h5>Arguments:</h5>
3567<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3568the condition code indicating the kind of comparison to perform. It is not
3569a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3570<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3571 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3572 <li><tt>oeq</tt>: ordered and equal</li>
3573 <li><tt>ogt</tt>: ordered and greater than </li>
3574 <li><tt>oge</tt>: ordered and greater than or equal</li>
3575 <li><tt>olt</tt>: ordered and less than </li>
3576 <li><tt>ole</tt>: ordered and less than or equal</li>
3577 <li><tt>one</tt>: ordered and not equal</li>
3578 <li><tt>ord</tt>: ordered (no nans)</li>
3579 <li><tt>ueq</tt>: unordered or equal</li>
3580 <li><tt>ugt</tt>: unordered or greater than </li>
3581 <li><tt>uge</tt>: unordered or greater than or equal</li>
3582 <li><tt>ult</tt>: unordered or less than </li>
3583 <li><tt>ule</tt>: unordered or less than or equal</li>
3584 <li><tt>une</tt>: unordered or not equal</li>
3585 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3586 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3587</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3588<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3589<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3590<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3591<a href="#t_floating">floating point</a> typed. They must have identical
3592types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3593<h5>Semantics:</h5>
3594<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3595the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3596yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3597<ol>
3598 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3599 <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]3600 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3601 <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]3602 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3603 <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]3604 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3605 <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]3606 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3607 <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]3608 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3609 <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]3610 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3611 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3612 <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]3613 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3614 <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]3615 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3616 <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]3617 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3618 <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]3619 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3620 <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]3621 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3622 <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]3623 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3624 <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]3625 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3626</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3627
3628<h5>Example:</h5>
3629<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3630 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3631 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3632 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3633</pre>
3634</div>
3635
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3636<!-- _______________________________________________________________________ -->
3637<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3638Instruction</a> </div>
3639<div class="doc_text">
3640<h5>Syntax:</h5>
3641<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3642<h5>Overview:</h5>
3643<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3644the SSA graph representing the function.</p>
3645<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3646<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3647field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3648as arguments, with one pair for each predecessor basic block of the
3649current block. Only values of <a href="#t_firstclass">first class</a>
3650type may be used as the value arguments to the PHI node. Only labels
3651may be used as the label arguments.</p>
3652<p>There must be no non-phi instructions between the start of a basic
3653block and the PHI instructions: i.e. PHI instructions must be first in
3654a basic block.</p>
3655<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3656<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3657specified by the pair corresponding to the predecessor basic block that executed
3658just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3659<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3660<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]3661</div>
3662
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3663<!-- _______________________________________________________________________ -->
3664<div class="doc_subsubsection">
3665 <a name="i_select">'<tt>select</tt>' Instruction</a>
3666</div>
3667
3668<div class="doc_text">
3669
3670<h5>Syntax:</h5>
3671
3672<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3673 &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]3674</pre>
3675
3676<h5>Overview:</h5>
3677
3678<p>
3679The '<tt>select</tt>' instruction is used to choose one value based on a
3680condition, without branching.
3681</p>
3682
3683
3684<h5>Arguments:</h5>
3685
3686<p>
3687The '<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.
3688</p>
3689
3690<h5>Semantics:</h5>
3691
3692<p>
3693If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3694value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3695</p>
3696
3697<h5>Example:</h5>
3698
3699<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3700 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3701</pre>
3702</div>
3703
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3704
3705<!-- _______________________________________________________________________ -->
3706<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3707 <a name="i_call">'<tt>call</tt>' Instruction</a>
3708</div>
3709
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3710<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3711
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3712<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3713<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3714 &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]3715</pre>
3716
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3717<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3718
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3719<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3720
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3721<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3722
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3723<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3724
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3725<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3726 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3727 <p>The optional "tail" marker indicates whether the callee function accesses
3728 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3729 function call is eligible for tail call optimization. Note that calls may
3730 be marked "tail" even if they do not occur before a <a
3731 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3732 </li>
3733 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3734 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3735 convention</a> the call should use. If none is specified, the call defaults
3736 to using C calling conventions.
3737 </li>
3738 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3739 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
3740 the type of the return value. Functions that return no value are marked
3741 <tt><a href="#t_void">void</a></tt>.</p>
3742 </li>
3743 <li>
3744 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
3745 value being invoked. The argument types must match the types implied by
3746 this signature. This type can be omitted if the function is not varargs
3747 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3748 </li>
3749 <li>
3750 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3751 be invoked. In most cases, this is a direct function invocation, but
3752 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3753 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3754 </li>
3755 <li>
3756 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3757 function signature argument types. All arguments must be of
3758 <a href="#t_firstclass">first class</a> type. If the function signature
3759 indicates the function accepts a variable number of arguments, the extra
3760 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3761 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3762</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3763
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3764<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3765
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3766<p>The '<tt>call</tt>' instruction is used to cause control flow to
3767transfer to a specified function, with its incoming arguments bound to
3768the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3769instruction in the called function, control flow continues with the
3770instruction after the function call, and the return value of the
3771function is bound to the result argument. This is a simpler case of
3772the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3773
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3774<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3775
3776<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]3777 %retval = call i32 @test(i32 %argc)
3778 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42);
3779 %X = tail call i32 @foo()
3780 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo()
3781 %Z = call void %foo(i8 97 signext)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3782</pre>
3783
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3784</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3785
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3786<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3787<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3788 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3789</div>
3790
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3791<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3792
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3793<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3794
3795<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3796 &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]3797</pre>
3798
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3799<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3800
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3801<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3802the "variable argument" area of a function call. It is used to implement the
3803<tt>va_arg</tt> macro in C.</p>
3804
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3805<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3806
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3807<p>This instruction takes a <tt>va_list*</tt> value and the type of
3808the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3809increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3810actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3811
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3812<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3813
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3814<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3815type from the specified <tt>va_list</tt> and causes the
3816<tt>va_list</tt> to point to the next argument. For more information,
3817see the variable argument handling <a href="#int_varargs">Intrinsic
3818Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3819
3820<p>It is legal for this instruction to be called in a function which does not
3821take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3822function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3823
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3824<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3825href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3826argument.</p>
3827
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3828<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3829
3830<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3831
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3832</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3833
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3834<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3835<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3836<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3837
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3838<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3839
3840<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3841well known names and semantics and are required to follow certain restrictions.
3842Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3843language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]3844adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3845
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3846<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3847prefix is reserved in LLVM for intrinsic names; thus, function names may not
3848begin with this prefix. Intrinsic functions must always be external functions:
3849you cannot define the body of intrinsic functions. Intrinsic functions may
3850only be used in call or invoke instructions: it is illegal to take the address
3851of an intrinsic function. Additionally, because intrinsic functions are part
3852of the LLVM language, it is required if any are added that they be documented
3853here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3854
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3855<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
3856a family of functions that perform the same operation but on different data
3857types. Because LLVM can represent over 8 million different integer types,
3858overloading is used commonly to allow an intrinsic function to operate on any
3859integer type. One or more of the argument types or the result type can be
3860overloaded to accept any integer type. Argument types may also be defined as
3861exactly matching a previous argument's type or the result type. This allows an
3862intrinsic function which accepts multiple arguments, but needs all of them to
3863be of the same type, to only be overloaded with respect to a single argument or
3864the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3865
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]3866<p>Overloaded intrinsics will have the names of its overloaded argument types
3867encoded into its function name, each preceded by a period. Only those types
3868which are overloaded result in a name suffix. Arguments whose type is matched
3869against another type do not. For example, the <tt>llvm.ctpop</tt> function can
3870take an integer of any width and returns an integer of exactly the same integer
3871width. This leads to a family of functions such as
3872<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
3873Only one type, the return type, is overloaded, and only one type suffix is
3874required. Because the argument's type is matched against the return type, it
3875does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3876
3877<p>To learn how to add an intrinsic function, please see the
3878<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3879</p>
3880
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3881</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3882
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3883<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3884<div class="doc_subsection">
3885 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3886</div>
3887
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3888<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3889
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3890<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3891 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3892intrinsic functions. These functions are related to the similarly
3893named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3894
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3895<p>All of these functions operate on arguments that use a
3896target-specific value type "<tt>va_list</tt>". The LLVM assembly
3897language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3898transformations should be prepared to handle these functions regardless of
3899the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3900
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3901<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]3902instruction and the variable argument handling intrinsic functions are
3903used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3904
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3905<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3906<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3907define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3908 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3909 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3910 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3911 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3912
3913 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3914 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3915
3916 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3917 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3918 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3919 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3920 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3921
3922 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3923 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3924 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3925}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3926
3927declare void @llvm.va_start(i8*)
3928declare void @llvm.va_copy(i8*, i8*)
3929declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3930</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3931</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3932
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3933</div>
3934
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3935<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3936<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3937 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3938</div>
3939
3940
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3941<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3942<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3943<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3944<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3945<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3946<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3947href="#i_va_arg">va_arg</a></tt>.</p>
3948
3949<h5>Arguments:</h5>
3950
3951<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3952
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3953<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3954
3955<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3956macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3957<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]3958<tt>va_arg</tt> will produce the first variable argument passed to the function.
3959Unlike 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]3960last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3961
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3962</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3963
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3964<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3965<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3966 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3967</div>
3968
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3969<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3970<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3971<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3972<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3973
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3974<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3975which 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]3976or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3977
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3978<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3979
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3980<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]3981
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3982<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3983
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3984<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]3985macro available in C. In a target-dependent way, it destroys the
3986<tt>va_list</tt> element to which the argument points. Calls to <a
3987href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3988<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3989<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3990
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3991</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3992
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3993<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3994<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3995 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3996</div>
3997
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3998<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3999
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4000<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4001
4002<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4003 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4004</pre>
4005
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4006<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4007
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4008<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4009from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4010
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4011<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4012
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]4013<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]4014The 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]4015
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4016
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]4017<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4018
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]4019<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4020macro available in C. In a target-dependent way, it copies the source
4021<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4022intrinsic is necessary because the <tt><a href="#int_va_start">
4023llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4024example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4025
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4026</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4027
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4028<!-- ======================================================================= -->
4029<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4030 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4031</div>
4032
4033<div class="doc_text">
4034
4035<p>
4036LLVM support for <a href="GarbageCollection.html">Accurate Garbage
4037Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4038These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4039stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4040href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4041Front-ends for type-safe garbage collected languages should generate these
4042intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4043href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4044</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]4045
4046<p>The garbage collection intrinsics only operate on objects in the generic
4047 address space (address space zero).</p>
4048
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4049</div>
4050
4051<!-- _______________________________________________________________________ -->
4052<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4053 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4054</div>
4055
4056<div class="doc_text">
4057
4058<h5>Syntax:</h5>
4059
4060<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4061 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4062</pre>
4063
4064<h5>Overview:</h5>
4065
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]4066<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]4067the code generator, and allows some metadata to be associated with it.</p>
4068
4069<h5>Arguments:</h5>
4070
4071<p>The first argument specifies the address of a stack object that contains the
4072root pointer. The second pointer (which must be either a constant or a global
4073value address) contains the meta-data to be associated with the root.</p>
4074
4075<h5>Semantics:</h5>
4076
4077<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
4078location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4079the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4080intrinsic may only be used in a function which <a href="#gc">specifies a GC
4081algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4082
4083</div>
4084
4085
4086<!-- _______________________________________________________________________ -->
4087<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4088 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4089</div>
4090
4091<div class="doc_text">
4092
4093<h5>Syntax:</h5>
4094
4095<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4096 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4097</pre>
4098
4099<h5>Overview:</h5>
4100
4101<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4102locations, allowing garbage collector implementations that require read
4103barriers.</p>
4104
4105<h5>Arguments:</h5>
4106
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4107<p>The second argument is the address to read from, which should be an address
4108allocated from the garbage collector. The first object is a pointer to the
4109start of the referenced object, if needed by the language runtime (otherwise
4110null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4111
4112<h5>Semantics:</h5>
4113
4114<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4115instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +0000[diff] [blame]4116garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4117may 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_gcwrite">'<tt>llvm.gcwrite</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 void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4134</pre>
4135
4136<h5>Overview:</h5>
4137
4138<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4139locations, allowing garbage collector implementations that require write
4140barriers (such as generational or reference counting collectors).</p>
4141
4142<h5>Arguments:</h5>
4143
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]4144<p>The first argument is the reference to store, the second is the start of the
4145object to store it to, and the third is the address of the field of Obj to
4146store to. If the runtime does not require a pointer to the object, Obj may be
4147null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]4148
4149<h5>Semantics:</h5>
4150
4151<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
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.gcwrite</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<!-- ======================================================================= -->
4162<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4163 <a name="int_codegen">Code Generator Intrinsics</a>
4164</div>
4165
4166<div class="doc_text">
4167<p>
4168These intrinsics are provided by LLVM to expose special features that may only
4169be implemented with code generator support.
4170</p>
4171
4172</div>
4173
4174<!-- _______________________________________________________________________ -->
4175<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4176 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4177</div>
4178
4179<div class="doc_text">
4180
4181<h5>Syntax:</h5>
4182<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4183 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4184</pre>
4185
4186<h5>Overview:</h5>
4187
4188<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4189The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4190target-specific value indicating the return address of the current function
4191or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4192</p>
4193
4194<h5>Arguments:</h5>
4195
4196<p>
4197The argument to this intrinsic indicates which function to return the address
4198for. Zero indicates the calling function, one indicates its caller, etc. The
4199argument is <b>required</b> to be a constant integer value.
4200</p>
4201
4202<h5>Semantics:</h5>
4203
4204<p>
4205The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4206the return address of the specified call frame, or zero if it cannot be
4207identified. The value returned by this intrinsic is likely to be incorrect or 0
4208for arguments other than zero, so it should only be used for debugging purposes.
4209</p>
4210
4211<p>
4212Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4213aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4214source-language caller.
4215</p>
4216</div>
4217
4218
4219<!-- _______________________________________________________________________ -->
4220<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4221 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4222</div>
4223
4224<div class="doc_text">
4225
4226<h5>Syntax:</h5>
4227<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4228 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4229</pre>
4230
4231<h5>Overview:</h5>
4232
4233<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4234The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4235target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4236</p>
4237
4238<h5>Arguments:</h5>
4239
4240<p>
4241The argument to this intrinsic indicates which function to return the frame
4242pointer for. Zero indicates the calling function, one indicates its caller,
4243etc. The argument is <b>required</b> to be a constant integer value.
4244</p>
4245
4246<h5>Semantics:</h5>
4247
4248<p>
4249The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4250the frame address of the specified call frame, or zero if it cannot be
4251identified. The value returned by this intrinsic is likely to be incorrect or 0
4252for arguments other than zero, so it should only be used for debugging purposes.
4253</p>
4254
4255<p>
4256Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4257aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4258source-language caller.
4259</p>
4260</div>
4261
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4262<!-- _______________________________________________________________________ -->
4263<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4264 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4265</div>
4266
4267<div class="doc_text">
4268
4269<h5>Syntax:</h5>
4270<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4271 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4272</pre>
4273
4274<h5>Overview:</h5>
4275
4276<p>
4277The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4278the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4279<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4280features like scoped automatic variable sized arrays in C99.
4281</p>
4282
4283<h5>Semantics:</h5>
4284
4285<p>
4286This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4287href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4288<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4289<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4290state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4291practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4292that were allocated after the <tt>llvm.stacksave</tt> was executed.
4293</p>
4294
4295</div>
4296
4297<!-- _______________________________________________________________________ -->
4298<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4299 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4300</div>
4301
4302<div class="doc_text">
4303
4304<h5>Syntax:</h5>
4305<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4306 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4307</pre>
4308
4309<h5>Overview:</h5>
4310
4311<p>
4312The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4313the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4314href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4315useful for implementing language features like scoped automatic variable sized
4316arrays in C99.
4317</p>
4318
4319<h5>Semantics:</h5>
4320
4321<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4322See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4323</p>
4324
4325</div>
4326
4327
4328<!-- _______________________________________________________________________ -->
4329<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4330 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4331</div>
4332
4333<div class="doc_text">
4334
4335<h5>Syntax:</h5>
4336<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4337 declare 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]4338</pre>
4339
4340<h5>Overview:</h5>
4341
4342
4343<p>
4344The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4345a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4346no
4347effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4348characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4349</p>
4350
4351<h5>Arguments:</h5>
4352
4353<p>
4354<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4355determining if the fetch should be for a read (0) or write (1), and
4356<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4357locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4358<tt>locality</tt> arguments must be constant integers.
4359</p>
4360
4361<h5>Semantics:</h5>
4362
4363<p>
4364This intrinsic does not modify the behavior of the program. In particular,
4365prefetches cannot trap and do not produce a value. On targets that support this
4366intrinsic, the prefetch can provide hints to the processor cache for better
4367performance.
4368</p>
4369
4370</div>
4371
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4372<!-- _______________________________________________________________________ -->
4373<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4374 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4375</div>
4376
4377<div class="doc_text">
4378
4379<h5>Syntax:</h5>
4380<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]4381 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4382</pre>
4383
4384<h5>Overview:</h5>
4385
4386
4387<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4388The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4389(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4390code to simulators and other tools. The method is target specific, but it is
4391expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4392The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4393after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4394optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4395correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4396</p>
4397
4398<h5>Arguments:</h5>
4399
4400<p>
4401<tt>id</tt> is a numerical id identifying the marker.
4402</p>
4403
4404<h5>Semantics:</h5>
4405
4406<p>
4407This intrinsic does not modify the behavior of the program. Backends that do not
4408support this intrinisic may ignore it.
4409</p>
4410
4411</div>
4412
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4413<!-- _______________________________________________________________________ -->
4414<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4415 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4416</div>
4417
4418<div class="doc_text">
4419
4420<h5>Syntax:</h5>
4421<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4422 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4423</pre>
4424
4425<h5>Overview:</h5>
4426
4427
4428<p>
4429The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4430counter register (or similar low latency, high accuracy clocks) on those targets
4431that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4432As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4433should only be used for small timings.
4434</p>
4435
4436<h5>Semantics:</h5>
4437
4438<p>
4439When directly supported, reading the cycle counter should not modify any memory.
4440Implementations are allowed to either return a application specific value or a
4441system wide value. On backends without support, this is lowered to a constant 0.
4442</p>
4443
4444</div>
4445
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4446<!-- ======================================================================= -->
4447<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4448 <a name="int_libc">Standard C Library Intrinsics</a>
4449</div>
4450
4451<div class="doc_text">
4452<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4453LLVM provides intrinsics for a few important standard C library functions.
4454These intrinsics allow source-language front-ends to pass information about the
4455alignment of the pointer arguments to the code generator, providing opportunity
4456for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4457</p>
4458
4459</div>
4460
4461<!-- _______________________________________________________________________ -->
4462<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4463 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4464</div>
4465
4466<div class="doc_text">
4467
4468<h5>Syntax:</h5>
4469<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4470 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4471 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4472 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4473 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4474</pre>
4475
4476<h5>Overview:</h5>
4477
4478<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4479The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4480location to the destination location.
4481</p>
4482
4483<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4484Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4485intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4486</p>
4487
4488<h5>Arguments:</h5>
4489
4490<p>
4491The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4492the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4493specifying the number of bytes to copy, and the fourth argument is the alignment
4494of the source and destination locations.
4495</p>
4496
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4497<p>
4498If 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]4499the caller guarantees that both the source and destination pointers are aligned
4500to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4501</p>
4502
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4503<h5>Semantics:</h5>
4504
4505<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4506The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4507location to the destination location, which are not allowed to overlap. It
4508copies "len" bytes of memory over. If the argument is known to be aligned to
4509some boundary, this can be specified as the fourth argument, otherwise it should
4510be set to 0 or 1.
4511</p>
4512</div>
4513
4514
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4515<!-- _______________________________________________________________________ -->
4516<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4517 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4518</div>
4519
4520<div class="doc_text">
4521
4522<h5>Syntax:</h5>
4523<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4524 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4525 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4526 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4527 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4528</pre>
4529
4530<h5>Overview:</h5>
4531
4532<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4533The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4534location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +0000[diff] [blame]4535'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4536</p>
4537
4538<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4539Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4540intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4541</p>
4542
4543<h5>Arguments:</h5>
4544
4545<p>
4546The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4547the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4548specifying the number of bytes to copy, and the fourth argument is the alignment
4549of the source and destination locations.
4550</p>
4551
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4552<p>
4553If 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]4554the caller guarantees that the source and destination pointers are aligned to
4555that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4556</p>
4557
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4558<h5>Semantics:</h5>
4559
4560<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4561The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4562location to the destination location, which may overlap. It
4563copies "len" bytes of memory over. If the argument is known to be aligned to
4564some boundary, this can be specified as the fourth argument, otherwise it should
4565be set to 0 or 1.
4566</p>
4567</div>
4568
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4569
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4570<!-- _______________________________________________________________________ -->
4571<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4572 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4573</div>
4574
4575<div class="doc_text">
4576
4577<h5>Syntax:</h5>
4578<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4579 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4580 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4581 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4582 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4583</pre>
4584
4585<h5>Overview:</h5>
4586
4587<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4588The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4589byte value.
4590</p>
4591
4592<p>
4593Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4594does not return a value, and takes an extra alignment argument.
4595</p>
4596
4597<h5>Arguments:</h5>
4598
4599<p>
4600The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4601byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4602argument specifying the number of bytes to fill, and the fourth argument is the
4603known alignment of destination location.
4604</p>
4605
4606<p>
4607If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4608the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4609</p>
4610
4611<h5>Semantics:</h5>
4612
4613<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4614The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4615the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4616destination location. If the argument is known to be aligned to some boundary,
4617this can be specified as the fourth argument, otherwise it should be set to 0 or
46181.
4619</p>
4620</div>
4621
4622
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4623<!-- _______________________________________________________________________ -->
4624<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4625 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4626</div>
4627
4628<div class="doc_text">
4629
4630<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4631<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]4632floating point or vector of floating point type. Not all targets support all
4633types however.
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4634<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4635 declare float @llvm.sqrt.f32(float %Val)
4636 declare double @llvm.sqrt.f64(double %Val)
4637 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
4638 declare fp128 @llvm.sqrt.f128(fp128 %Val)
4639 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4640</pre>
4641
4642<h5>Overview:</h5>
4643
4644<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4645The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4646returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4647<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4648negative numbers (which allows for better optimization).
4649</p>
4650
4651<h5>Arguments:</h5>
4652
4653<p>
4654The argument and return value are floating point numbers of the same type.
4655</p>
4656
4657<h5>Semantics:</h5>
4658
4659<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]4660This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4661floating point number.
4662</p>
4663</div>
4664
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4665<!-- _______________________________________________________________________ -->
4666<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4667 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4668</div>
4669
4670<div class="doc_text">
4671
4672<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4673<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]4674floating point or vector of floating point type. Not all targets support all
4675types however.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4676<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]4677 declare float @llvm.powi.f32(float %Val, i32 %power)
4678 declare double @llvm.powi.f64(double %Val, i32 %power)
4679 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
4680 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
4681 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4682</pre>
4683
4684<h5>Overview:</h5>
4685
4686<p>
4687The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4688specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4689multiplications is not defined. When a vector of floating point type is
4690used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4691</p>
4692
4693<h5>Arguments:</h5>
4694
4695<p>
4696The second argument is an integer power, and the first is a value to raise to
4697that power.
4698</p>
4699
4700<h5>Semantics:</h5>
4701
4702<p>
4703This function returns the first value raised to the second power with an
4704unspecified sequence of rounding operations.</p>
4705</div>
4706
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4707<!-- _______________________________________________________________________ -->
4708<div class="doc_subsubsection">
4709 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
4710</div>
4711
4712<div class="doc_text">
4713
4714<h5>Syntax:</h5>
4715<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
4716floating point or vector of floating point type. Not all targets support all
4717types however.
4718<pre>
4719 declare float @llvm.sin.f32(float %Val)
4720 declare double @llvm.sin.f64(double %Val)
4721 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
4722 declare fp128 @llvm.sin.f128(fp128 %Val)
4723 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
4724</pre>
4725
4726<h5>Overview:</h5>
4727
4728<p>
4729The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
4730</p>
4731
4732<h5>Arguments:</h5>
4733
4734<p>
4735The argument and return value are floating point numbers of the same type.
4736</p>
4737
4738<h5>Semantics:</h5>
4739
4740<p>
4741This function returns the sine of the specified operand, returning the
4742same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4743conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4744</div>
4745
4746<!-- _______________________________________________________________________ -->
4747<div class="doc_subsubsection">
4748 <a name="int_cos">'<tt>llvm.cos.*</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.cos</tt> on any
4755floating point or vector of floating point type. Not all targets support all
4756types however.
4757<pre>
4758 declare float @llvm.cos.f32(float %Val)
4759 declare double @llvm.cos.f64(double %Val)
4760 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
4761 declare fp128 @llvm.cos.f128(fp128 %Val)
4762 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
4763</pre>
4764
4765<h5>Overview:</h5>
4766
4767<p>
4768The '<tt>llvm.cos.*</tt>' intrinsics return the cosine 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 cosine of the specified operand, returning the
4781same values as the libm <tt>cos</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_pow">'<tt>llvm.pow.*</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.pow</tt> on any
4794floating point or vector of floating point type. Not all targets support all
4795types however.
4796<pre>
4797 declare float @llvm.pow.f32(float %Val, float %Power)
4798 declare double @llvm.pow.f64(double %Val, double %Power)
4799 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
4800 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
4801 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
4802</pre>
4803
4804<h5>Overview:</h5>
4805
4806<p>
4807The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
4808specified (positive or negative) power.
4809</p>
4810
4811<h5>Arguments:</h5>
4812
4813<p>
4814The second argument is a floating point power, and the first is a value to
4815raise to that power.
4816</p>
4817
4818<h5>Semantics:</h5>
4819
4820<p>
4821This function returns the first value raised to the second power,
4822returning the
4823same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +0000[diff] [blame]4824conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]4825</div>
4826
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4827
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4828<!-- ======================================================================= -->
4829<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4830 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4831</div>
4832
4833<div class="doc_text">
4834<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4835LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4836These allow efficient code generation for some algorithms.
4837</p>
4838
4839</div>
4840
4841<!-- _______________________________________________________________________ -->
4842<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4843 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4844</div>
4845
4846<div class="doc_text">
4847
4848<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4849<p>This is an overloaded intrinsic function. You can use bswap on any integer
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4850type that is an even number of bytes (i.e. BitWidth % 16 == 0).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4851<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4852 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
4853 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
4854 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4855</pre>
4856
4857<h5>Overview:</h5>
4858
4859<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4860The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4861values with an even number of bytes (positive multiple of 16 bits). These are
4862useful for performing operations on data that is not in the target's native
4863byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4864</p>
4865
4866<h5>Semantics:</h5>
4867
4868<p>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4869The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4870and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4871intrinsic returns an i32 value that has the four bytes of the input i32
4872swapped, 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]4873i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
4874<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4875additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4876</p>
4877
4878</div>
4879
4880<!-- _______________________________________________________________________ -->
4881<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4882 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +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. You can use llvm.ctpop on any integer bit
4889width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4890<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4891 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4892 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4893 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4894 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
4895 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4896</pre>
4897
4898<h5>Overview:</h5>
4899
4900<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4901The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4902value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4903</p>
4904
4905<h5>Arguments:</h5>
4906
4907<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4908The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4909integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4910</p>
4911
4912<h5>Semantics:</h5>
4913
4914<p>
4915The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4916</p>
4917</div>
4918
4919<!-- _______________________________________________________________________ -->
4920<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4921 <a name="int_ctlz">'<tt>llvm.ctlz.*</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 <tt>llvm.ctlz</tt> on any
4928integer bit width. 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.ctlz.i8 (i8 &lt;src&gt;)
4931 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4932 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4933 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
4934 declare i256 @llvm.ctlz.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>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4940The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4941leading zeros in a variable.
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>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4954The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4955in 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]4956of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4957</p>
4958</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4959
4960
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4961
4962<!-- _______________________________________________________________________ -->
4963<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4964 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4965</div>
4966
4967<div class="doc_text">
4968
4969<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4970<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4971integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4972<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4973 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
4974 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4975 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]4976 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
4977 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4978</pre>
4979
4980<h5>Overview:</h5>
4981
4982<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4983The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4984trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4985</p>
4986
4987<h5>Arguments:</h5>
4988
4989<p>
4990The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4991integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4992</p>
4993
4994<h5>Semantics:</h5>
4995
4996<p>
4997The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4998in a variable. If the src == 0 then the result is the size in bits of the type
4999of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5000</p>
5001</div>
5002
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]5003<!-- _______________________________________________________________________ -->
5004<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5005 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5006</div>
5007
5008<div class="doc_text">
5009
5010<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5011<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5012on any integer bit width.
5013<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5014 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5015 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5016</pre>
5017
5018<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5019<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5020range of bits from an integer value and returns them in the same bit width as
5021the original value.</p>
5022
5023<h5>Arguments:</h5>
5024<p>The first argument, <tt>%val</tt> and the result may be integer types of
5025any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5026arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5027
5028<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]5029<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]5030of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5031<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5032operates in forward mode.</p>
5033<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5034right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5035only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5036<ol>
5037 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5038 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5039 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5040 to determine the number of bits to retain.</li>
5041 <li>A mask of the retained bits is created by shifting a -1 value.</li>
5042 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
5043</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]5044<p>In reverse mode, a similar computation is made except that the bits are
5045returned in the reverse order. So, for example, if <tt>X</tt> has the value
5046<tt>i16 0x0ACF (101011001111)</tt> and we apply
5047<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5048<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]5049</div>
5050
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5051<div class="doc_subsubsection">
5052 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5053</div>
5054
5055<div class="doc_text">
5056
5057<h5>Syntax:</h5>
5058<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
5059on any integer bit width.
5060<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]5061 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5062 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]5063</pre>
5064
5065<h5>Overview:</h5>
5066<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5067of bits in an integer value with another integer value. It returns the integer
5068with the replaced bits.</p>
5069
5070<h5>Arguments:</h5>
5071<p>The first argument, <tt>%val</tt> and the result may be integer types of
5072any bit width but they must have the same bit width. <tt>%val</tt> is the value
5073whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5074integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5075type since they specify only a bit index.</p>
5076
5077<h5>Semantics:</h5>
5078<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5079of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5080<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5081operates in forward mode.</p>
5082<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5083truncating it down to the size of the replacement area or zero extending it
5084up to that size.</p>
5085<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5086are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5087in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
5088to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5089<p>In reverse mode, a similar computation is made except that the bits are
5090reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
5091<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]5092<h5>Examples:</h5>
5093<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5094 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]5095 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5096 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5097 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]5098 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]5099</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]5100</div>
5101
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]5102<!-- ======================================================================= -->
5103<div class="doc_subsection">
5104 <a name="int_debugger">Debugger Intrinsics</a>
5105</div>
5106
5107<div class="doc_text">
5108<p>
5109The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5110are described in the <a
5111href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5112Debugging</a> document.
5113</p>
5114</div>
5115
5116
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5117<!-- ======================================================================= -->
5118<div class="doc_subsection">
5119 <a name="int_eh">Exception Handling Intrinsics</a>
5120</div>
5121
5122<div class="doc_text">
5123<p> The LLVM exception handling intrinsics (which all start with
5124<tt>llvm.eh.</tt> prefix), are described in the <a
5125href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5126Handling</a> document. </p>
5127</div>
5128
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5129<!-- ======================================================================= -->
5130<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5131 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5132</div>
5133
5134<div class="doc_text">
5135<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5136 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5137 the <tt>nest</tt> attribute, from a function. The result is a callable
5138 function pointer lacking the nest parameter - the caller does not need
5139 to provide a value for it. Instead, the value to use is stored in
5140 advance in a "trampoline", a block of memory usually allocated
5141 on the stack, which also contains code to splice the nest value into the
5142 argument list. This is used to implement the GCC nested function address
5143 extension.
5144</p>
5145<p>
5146 For example, if the function is
5147 <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]5148 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]5149<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5150 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5151 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5152 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5153 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5154</pre>
Bill Wendling252570f2007-09-22 09:23:55 +0000[diff] [blame]5155 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5156 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5157</div>
5158
5159<!-- _______________________________________________________________________ -->
5160<div class="doc_subsubsection">
5161 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5162</div>
5163<div class="doc_text">
5164<h5>Syntax:</h5>
5165<pre>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5166declare 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]5167</pre>
5168<h5>Overview:</h5>
5169<p>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5170 This fills the memory pointed to by <tt>tramp</tt> with code
5171 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5172</p>
5173<h5>Arguments:</h5>
5174<p>
5175 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5176 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5177 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +0000[diff] [blame]5178 intrinsic. Note that the size and the alignment are target-specific - LLVM
5179 currently provides no portable way of determining them, so a front-end that
5180 generates this intrinsic needs to have some target-specific knowledge.
5181 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]5182</p>
5183<h5>Semantics:</h5>
5184<p>
5185 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5186 dependent code, turning it into a function. A pointer to this function is
5187 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5188 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]5189 before being called. The new function's signature is the same as that of
5190 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5191 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5192 of pointer type. Calling the new function is equivalent to calling
5193 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5194 missing <tt>nest</tt> argument. If, after calling
5195 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5196 modified, then the effect of any later call to the returned function pointer is
5197 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]5198</p>
5199</div>
5200
5201<!-- ======================================================================= -->
5202<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5203 <a name="int_general">General Intrinsics</a>
5204</div>
5205
5206<div class="doc_text">
5207<p> This class of intrinsics is designed to be generic and has
5208no specific purpose. </p>
5209</div>
5210
5211<!-- _______________________________________________________________________ -->
5212<div class="doc_subsubsection">
5213 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5214</div>
5215
5216<div class="doc_text">
5217
5218<h5>Syntax:</h5>
5219<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5220 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]5221</pre>
5222
5223<h5>Overview:</h5>
5224
5225<p>
5226The '<tt>llvm.var.annotation</tt>' intrinsic
5227</p>
5228
5229<h5>Arguments:</h5>
5230
5231<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5232The first argument is a pointer to a value, the second is a pointer to a
5233global string, the third is a pointer to a global string which is the source
5234file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5235</p>
5236
5237<h5>Semantics:</h5>
5238
5239<p>
5240This intrinsic allows annotation of local variables with arbitrary strings.
5241This can be useful for special purpose optimizations that want to look for these
5242 annotations. These have no other defined use, they are ignored by code
5243 generation and optimization.
5244</div>
5245
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5246<!-- _______________________________________________________________________ -->
5247<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]5248 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5249</div>
5250
5251<div class="doc_text">
5252
5253<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5254<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
5255any integer bit width.
5256</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5257<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +0000[diff] [blame]5258 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5259 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5260 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5261 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
5262 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]5263</pre>
5264
5265<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5266
5267<p>
5268The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5269</p>
5270
5271<h5>Arguments:</h5>
5272
5273<p>
5274The first argument is an integer value (result of some expression),
5275the second is a pointer to a global string, the third is a pointer to a global
5276string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +0000[diff] [blame]5277It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]5278</p>
5279
5280<h5>Semantics:</h5>
5281
5282<p>
5283This intrinsic allows annotations to be put on arbitrary expressions
5284with arbitrary strings. This can be useful for special purpose optimizations
5285that want to look for these annotations. These have no other defined use, they
5286are ignored by code generation and optimization.
5287</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5288
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5289<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5290<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5291<address>
5292 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
5293 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
5294 <a href="http://validator.w3.org/check/referer"><img
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]5295 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5296
5297 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]5298 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]5299 Last modified: $Date$
5300</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]5301
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5302</body>
5303</html>