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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 5de585a57e8c89ba0f01b6b90a66a413692cc9cd / . / 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">
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]9 content="LLVM Assembly Language Reference Manual.">
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11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]28 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
29 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
30 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
31 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
32 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
33 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
34 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]35 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]36 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
37 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
39 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]40 </ol>
41 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]42 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]43 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]44 <li><a href="#globalvars">Global Variables</a></li>
45 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]46 <li><a href="#aliasstructure">Aliases</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]47 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]48 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]49 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]50 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]51 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
52 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]53 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]54 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]55 </ol>
56 </li>
57 <li><a href="#typesystem">Type System</a>
58 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]60 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]61 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]62 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]63 <li><a href="#t_floating">Floating Point Types</a></li>
64 <li><a href="#t_void">Void Type</a></li>
65 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]66 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]67 </ol>
68 </li>
69 <li><a href="#t_derived">Derived Types</a>
70 <ol>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]71 <li><a href="#t_aggregate">Aggregate Types</a>
72 <ol>
73 <li><a href="#t_array">Array Type</a></li>
74 <li><a href="#t_struct">Structure Type</a></li>
75 <li><a href="#t_pstruct">Packed Structure Type</a></li>
76 <li><a href="#t_union">Union Type</a></li>
77 <li><a href="#t_vector">Vector Type</a></li>
78 </ol>
79 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]80 <li><a href="#t_function">Function Type</a></li>
81 <li><a href="#t_pointer">Pointer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]82 <li><a href="#t_opaque">Opaque Type</a></li>
83 </ol>
84 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]85 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]86 </ol>
87 </li>
88 <li><a href="#constants">Constants</a>
89 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]90 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]91 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
93 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]94 <li><a href="#trapvalues">Trap Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]95 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]96 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]97 </ol>
98 </li>
99 <li><a href="#othervalues">Other Values</a>
100 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]101 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]102 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]103 </ol>
104 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]105 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
106 <ol>
107 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]108 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
109 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]110 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
111 Global Variable</a></li>
112 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
113 Global Variable</a></li>
114 </ol>
115 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]116 <li><a href="#instref">Instruction Reference</a>
117 <ol>
118 <li><a href="#terminators">Terminator Instructions</a>
119 <ol>
120 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
121 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
122 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]123 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
125 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
126 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
127 </ol>
128 </li>
129 <li><a href="#binaryops">Binary Operations</a>
130 <ol>
131 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]132 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]133 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]134 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]135 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]136 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]137 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
138 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
139 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
140 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
141 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
142 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
143 </ol>
144 </li>
145 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
146 <ol>
147 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
148 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
149 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
150 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
151 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
152 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
153 </ol>
154 </li>
155 <li><a href="#vectorops">Vector Operations</a>
156 <ol>
157 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
158 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
159 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
160 </ol>
161 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]162 <li><a href="#aggregateops">Aggregate Operations</a>
163 <ol>
164 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
165 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
166 </ol>
167 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]168 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
169 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]170 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
171 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
172 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
173 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
174 </ol>
175 </li>
176 <li><a href="#convertops">Conversion Operations</a>
177 <ol>
178 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
179 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
180 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
181 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
182 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
183 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
184 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
185 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
186 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
187 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
188 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
189 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
190 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]191 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]192 <li><a href="#otherops">Other Operations</a>
193 <ol>
194 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
195 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
196 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
197 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
198 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
199 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
200 </ol>
201 </li>
202 </ol>
203 </li>
204 <li><a href="#intrinsics">Intrinsic Functions</a>
205 <ol>
206 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
207 <ol>
208 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
209 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
210 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
211 </ol>
212 </li>
213 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
214 <ol>
215 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
216 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
217 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
218 </ol>
219 </li>
220 <li><a href="#int_codegen">Code Generator Intrinsics</a>
221 <ol>
222 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
223 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
224 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
225 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
226 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
227 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmanf15a6b22010-05-26 21:56:15 +0000[diff] [blame]228 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]229 </ol>
230 </li>
231 <li><a href="#int_libc">Standard C Library Intrinsics</a>
232 <ol>
233 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
234 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
235 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
236 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
237 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]238 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
239 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
240 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]241 </ol>
242 </li>
243 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
244 <ol>
245 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
246 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
247 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
248 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]249 </ol>
250 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]251 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
252 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]253 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
254 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
255 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
256 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
257 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]258 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]259 </ol>
260 </li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]261 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
262 <ol>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]263 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
264 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]265 </ol>
266 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]267 <li><a href="#int_debugger">Debugger intrinsics</a></li>
268 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]269 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]270 <ol>
271 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]272 </ol>
273 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]274 <li><a href="#int_atomics">Atomic intrinsics</a>
275 <ol>
276 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
277 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
278 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
279 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
280 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
281 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
282 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
283 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
284 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
285 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
286 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
287 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
288 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
289 </ol>
290 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]291 <li><a href="#int_memorymarkers">Memory Use Markers</a>
292 <ol>
293 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
294 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
295 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
296 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
297 </ol>
298 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]299 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]300 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]301 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]302 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]303 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]304 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]305 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]306 '<tt>llvm.trap</tt>' Intrinsic</a></li>
307 <li><a href="#int_stackprotector">
308 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]309 <li><a href="#int_objectsize">
310 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]311 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]312 </li>
313 </ol>
314 </li>
315</ol>
316
317<div class="doc_author">
318 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
319 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
320</div>
321
322<!-- *********************************************************************** -->
323<div class="doc_section"> <a name="abstract">Abstract </a></div>
324<!-- *********************************************************************** -->
325
326<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]327
328<p>This document is a reference manual for the LLVM assembly language. LLVM is
329 a Static Single Assignment (SSA) based representation that provides type
330 safety, low-level operations, flexibility, and the capability of representing
331 'all' high-level languages cleanly. It is the common code representation
332 used throughout all phases of the LLVM compilation strategy.</p>
333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334</div>
335
336<!-- *********************************************************************** -->
337<div class="doc_section"> <a name="introduction">Introduction</a> </div>
338<!-- *********************************************************************** -->
339
340<div class="doc_text">
341
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342<p>The LLVM code representation is designed to be used in three different forms:
343 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
344 for fast loading by a Just-In-Time compiler), and as a human readable
345 assembly language representation. This allows LLVM to provide a powerful
346 intermediate representation for efficient compiler transformations and
347 analysis, while providing a natural means to debug and visualize the
348 transformations. The three different forms of LLVM are all equivalent. This
349 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]350
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]351<p>The LLVM representation aims to be light-weight and low-level while being
352 expressive, typed, and extensible at the same time. It aims to be a
353 "universal IR" of sorts, by being at a low enough level that high-level ideas
354 may be cleanly mapped to it (similar to how microprocessors are "universal
355 IR's", allowing many source languages to be mapped to them). By providing
356 type information, LLVM can be used as the target of optimizations: for
357 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]358 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]359 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]360
361</div>
362
363<!-- _______________________________________________________________________ -->
364<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
365
366<div class="doc_text">
367
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]368<p>It is important to note that this document describes 'well formed' LLVM
369 assembly language. There is a difference between what the parser accepts and
370 what is considered 'well formed'. For example, the following instruction is
371 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]373<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]374%x = <a href="#i_add">add</a> i32 1, %x
375</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]376
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]377<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
378 LLVM infrastructure provides a verification pass that may be used to verify
379 that an LLVM module is well formed. This pass is automatically run by the
380 parser after parsing input assembly and by the optimizer before it outputs
381 bitcode. The violations pointed out by the verifier pass indicate bugs in
382 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]384</div>
385
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]386<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]387
388<!-- *********************************************************************** -->
389<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
390<!-- *********************************************************************** -->
391
392<div class="doc_text">
393
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]394<p>LLVM identifiers come in two basic types: global and local. Global
395 identifiers (functions, global variables) begin with the <tt>'@'</tt>
396 character. Local identifiers (register names, types) begin with
397 the <tt>'%'</tt> character. Additionally, there are three different formats
398 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399
400<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]401 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]402 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
403 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
404 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
405 other characters in their names can be surrounded with quotes. Special
406 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
407 ASCII code for the character in hexadecimal. In this way, any character
408 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]410 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]412
413 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]414 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]415</ol>
416
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]417<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]418 don't need to worry about name clashes with reserved words, and the set of
419 reserved words may be expanded in the future without penalty. Additionally,
420 unnamed identifiers allow a compiler to quickly come up with a temporary
421 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]422
423<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]424 languages. There are keywords for different opcodes
425 ('<tt><a href="#i_add">add</a></tt>',
426 '<tt><a href="#i_bitcast">bitcast</a></tt>',
427 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
428 ('<tt><a href="#t_void">void</a></tt>',
429 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
430 reserved words cannot conflict with variable names, because none of them
431 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]432
433<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]434 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]435
436<p>The easy way:</p>
437
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]438<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]439%result = <a href="#i_mul">mul</a> i32 %X, 8
440</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441
442<p>After strength reduction:</p>
443
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]444<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]445%result = <a href="#i_shl">shl</a> i32 %X, i8 3
446</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447
448<p>And the hard way:</p>
449
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]450<pre class="doc_code">
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]451%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
452%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453%result = <a href="#i_add">add</a> i32 %1, %1
454</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]455
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]456<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
457 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458
459<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]460 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]461 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]462
463 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]464 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]465
466 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]467</ol>
468
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]469<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]470 demonstrating instructions, we will follow an instruction with a comment that
471 defines the type and name of value produced. Comments are shown in italic
472 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]473
474</div>
475
476<!-- *********************************************************************** -->
477<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
478<!-- *********************************************************************** -->
479
480<!-- ======================================================================= -->
481<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
482</div>
483
484<div class="doc_text">
485
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]486<p>LLVM programs are composed of "Module"s, each of which is a translation unit
487 of the input programs. Each module consists of functions, global variables,
488 and symbol table entries. Modules may be combined together with the LLVM
489 linker, which merges function (and global variable) definitions, resolves
490 forward declarations, and merges symbol table entries. Here is an example of
491 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]492
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]493<pre class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]494<i>; Declare the string constant as a global constant.</i>
495<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]496
497<i>; External declaration of the puts function</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]498<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]499
500<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]501define i32 @main() { <i>; i32()* </i>
502 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]503 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]504
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]505 <i>; Call puts function to write out the string to stdout.</i>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]506 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]507 <a href="#i_ret">ret</a> i32 0<br>}
508
509<i>; Named metadata</i>
510!1 = metadata !{i32 41}
511!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]512</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]513
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]514<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]515 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]516 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]517 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
518 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]520<p>In general, a module is made up of a list of global values, where both
521 functions and global variables are global values. Global values are
522 represented by a pointer to a memory location (in this case, a pointer to an
523 array of char, and a pointer to a function), and have one of the
524 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]525
526</div>
527
528<!-- ======================================================================= -->
529<div class="doc_subsection">
530 <a name="linkage">Linkage Types</a>
531</div>
532
533<div class="doc_text">
534
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]535<p>All Global Variables and Functions have one of the following types of
536 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]537
538<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]539 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]540 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
541 by objects in the current module. In particular, linking code into a
542 module with an private global value may cause the private to be renamed as
543 necessary to avoid collisions. Because the symbol is private to the
544 module, all references can be updated. This doesn't show up in any symbol
545 table in the object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]546
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]547 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]548 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
549 assembler and evaluated by the linker. Unlike normal strong symbols, they
550 are removed by the linker from the final linked image (executable or
551 dynamic library).</dd>
552
553 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
554 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
555 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
556 linker. The symbols are removed by the linker from the final linked image
557 (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]558
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlinge066d262010-06-29 22:34:52 +0000[diff] [blame]560 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]561 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
562 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]563
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]565 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]566 into the object file corresponding to the LLVM module. They exist to
567 allow inlining and other optimizations to take place given knowledge of
568 the definition of the global, which is known to be somewhere outside the
569 module. Globals with <tt>available_externally</tt> linkage are allowed to
570 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
571 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]572
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]573 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]574 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]575 the same name when linkage occurs. This can be used to implement
576 some forms of inline functions, templates, or other code which must be
577 generated in each translation unit that uses it, but where the body may
578 be overridden with a more definitive definition later. Unreferenced
579 <tt>linkonce</tt> globals are allowed to be discarded. Note that
580 <tt>linkonce</tt> linkage does not actually allow the optimizer to
581 inline the body of this function into callers because it doesn't know if
582 this definition of the function is the definitive definition within the
583 program or whether it will be overridden by a stronger definition.
584 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
585 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]586
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]587 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]588 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
589 <tt>linkonce</tt> linkage, except that unreferenced globals with
590 <tt>weak</tt> linkage may not be discarded. This is used for globals that
591 are declared "weak" in C source code.</dd>
592
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]593 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]594 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
595 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
596 global scope.
597 Symbols with "<tt>common</tt>" linkage are merged in the same way as
598 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]599 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]600 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]601 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
602 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]604
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]605 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]607 pointer to array type. When two global variables with appending linkage
608 are linked together, the two global arrays are appended together. This is
609 the LLVM, typesafe, equivalent of having the system linker append together
610 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]612 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]613 <dd>The semantics of this linkage follow the ELF object file model: the symbol
614 is weak until linked, if not linked, the symbol becomes null instead of
615 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
618 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]619 <dd>Some languages allow differing globals to be merged, such as two functions
620 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendlingf8239662010-07-01 21:55:59 +0000[diff] [blame]621 that only equivalent globals are ever merged (the "one definition rule"
622 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]623 and <tt>weak_odr</tt> linkage types to indicate that the global will only
624 be merged with equivalent globals. These linkage types are otherwise the
625 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]627 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]629 visible, meaning that it participates in linkage and can be used to
630 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]631</dl>
632
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]633<p>The next two types of linkage are targeted for Microsoft Windows platform
634 only. They are designed to support importing (exporting) symbols from (to)
635 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]636
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]637<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]638 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]639 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]640 or variable via a global pointer to a pointer that is set up by the DLL
641 exporting the symbol. On Microsoft Windows targets, the pointer name is
642 formed by combining <code>__imp_</code> and the function or variable
643 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]644
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]645 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]646 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]647 pointer to a pointer in a DLL, so that it can be referenced with the
648 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
649 name is formed by combining <code>__imp_</code> and the function or
650 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]651</dl>
652
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]653<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
654 another module defined a "<tt>.LC0</tt>" variable and was linked with this
655 one, one of the two would be renamed, preventing a collision. Since
656 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
657 declarations), they are accessible outside of the current module.</p>
658
659<p>It is illegal for a function <i>declaration</i> to have any linkage type
660 other than "externally visible", <tt>dllimport</tt>
661 or <tt>extern_weak</tt>.</p>
662
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]663<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]664 or <tt>weak_odr</tt> linkages.</p>
665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]666</div>
667
668<!-- ======================================================================= -->
669<div class="doc_subsection">
670 <a name="callingconv">Calling Conventions</a>
671</div>
672
673<div class="doc_text">
674
675<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]676 and <a href="#i_invoke">invokes</a> can all have an optional calling
677 convention specified for the call. The calling convention of any pair of
678 dynamic caller/callee must match, or the behavior of the program is
679 undefined. The following calling conventions are supported by LLVM, and more
680 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681
682<dl>
683 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]684 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]685 specified) matches the target C calling conventions. This calling
686 convention supports varargs function calls and tolerates some mismatch in
687 the declared prototype and implemented declaration of the function (as
688 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689
690 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]691 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]692 (e.g. by passing things in registers). This calling convention allows the
693 target to use whatever tricks it wants to produce fast code for the
694 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]695 (Application Binary Interface).
696 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]697 when this or the GHC convention is used.</a> This calling convention
698 does not support varargs and requires the prototype of all callees to
699 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700
701 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]703 as possible under the assumption that the call is not commonly executed.
704 As such, these calls often preserve all registers so that the call does
705 not break any live ranges in the caller side. This calling convention
706 does not support varargs and requires the prototype of all callees to
707 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]708
Chris Lattnerac9a9392010-03-11 00:22:57 +0000[diff] [blame]709 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
710 <dd>This calling convention has been implemented specifically for use by the
711 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
712 It passes everything in registers, going to extremes to achieve this by
713 disabling callee save registers. This calling convention should not be
714 used lightly but only for specific situations such as an alternative to
715 the <em>register pinning</em> performance technique often used when
716 implementing functional programming languages.At the moment only X86
717 supports this convention and it has the following limitations:
718 <ul>
719 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
720 floating point types are supported.</li>
721 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
722 6 floating point parameters.</li>
723 </ul>
724 This calling convention supports
725 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
726 requires both the caller and callee are using it.
727 </dd>
728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]729 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]730 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]731 target-specific calling conventions to be used. Target specific calling
732 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733</dl>
734
735<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]736 support Pascal conventions or any other well-known target-independent
737 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]738
739</div>
740
741<!-- ======================================================================= -->
742<div class="doc_subsection">
743 <a name="visibility">Visibility Styles</a>
744</div>
745
746<div class="doc_text">
747
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]748<p>All Global Variables and Functions have one of the following visibility
749 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]750
751<dl>
752 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]753 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]754 that the declaration is visible to other modules and, in shared libraries,
755 means that the declared entity may be overridden. On Darwin, default
756 visibility means that the declaration is visible to other modules. Default
757 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]758
759 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]760 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]761 object if they are in the same shared object. Usually, hidden visibility
762 indicates that the symbol will not be placed into the dynamic symbol
763 table, so no other module (executable or shared library) can reference it
764 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]765
766 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]767 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]768 the dynamic symbol table, but that references within the defining module
769 will bind to the local symbol. That is, the symbol cannot be overridden by
770 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]771</dl>
772
773</div>
774
775<!-- ======================================================================= -->
776<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]777 <a name="namedtypes">Named Types</a>
778</div>
779
780<div class="doc_text">
781
782<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]783 it easier to read the IR and make the IR more condensed (particularly when
784 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]785
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]786<pre class="doc_code">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]787%mytype = type { %mytype*, i32 }
788</pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]789
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]790<p>You may give a name to any <a href="#typesystem">type</a> except
791 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
792 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]793
794<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]795 and that you can therefore specify multiple names for the same type. This
796 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
797 uses structural typing, the name is not part of the type. When printing out
798 LLVM IR, the printer will pick <em>one name</em> to render all types of a
799 particular shape. This means that if you have code where two different
800 source types end up having the same LLVM type, that the dumper will sometimes
801 print the "wrong" or unexpected type. This is an important design point and
802 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]803
804</div>
805
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]806<!-- ======================================================================= -->
807<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]808 <a name="globalvars">Global Variables</a>
809</div>
810
811<div class="doc_text">
812
813<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]814 instead of run-time. Global variables may optionally be initialized, may
815 have an explicit section to be placed in, and may have an optional explicit
816 alignment specified. A variable may be defined as "thread_local", which
817 means that it will not be shared by threads (each thread will have a
818 separated copy of the variable). A variable may be defined as a global
819 "constant," which indicates that the contents of the variable
820 will <b>never</b> be modified (enabling better optimization, allowing the
821 global data to be placed in the read-only section of an executable, etc).
822 Note that variables that need runtime initialization cannot be marked
823 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]824
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]825<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
826 constant, even if the final definition of the global is not. This capability
827 can be used to enable slightly better optimization of the program, but
828 requires the language definition to guarantee that optimizations based on the
829 'constantness' are valid for the translation units that do not include the
830 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]831
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]832<p>As SSA values, global variables define pointer values that are in scope
833 (i.e. they dominate) all basic blocks in the program. Global variables
834 always define a pointer to their "content" type because they describe a
835 region of memory, and all memory objects in LLVM are accessed through
836 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]838<p>A global variable may be declared to reside in a target-specific numbered
839 address space. For targets that support them, address spaces may affect how
840 optimizations are performed and/or what target instructions are used to
841 access the variable. The default address space is zero. The address space
842 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]845 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]846
Chris Lattner72413b22010-04-28 00:13:42 +0000[diff] [blame]847<p>An explicit alignment may be specified for a global, which must be a power
848 of 2. If not present, or if the alignment is set to zero, the alignment of
849 the global is set by the target to whatever it feels convenient. If an
850 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner50d07d02010-04-28 00:31:12 +0000[diff] [blame]851 alignment. Targets and optimizers are not allowed to over-align the global
852 if the global has an assigned section. In this case, the extra alignment
853 could be observable: for example, code could assume that the globals are
854 densely packed in their section and try to iterate over them as an array,
855 alignment padding would break this iteration.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]857<p>For example, the following defines a global in a numbered address space with
858 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]859
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]860<pre class="doc_code">
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]861@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]862</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]863
864</div>
865
866
867<!-- ======================================================================= -->
868<div class="doc_subsection">
869 <a name="functionstructure">Functions</a>
870</div>
871
872<div class="doc_text">
873
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]874<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]875 optional <a href="#linkage">linkage type</a>, an optional
876 <a href="#visibility">visibility style</a>, an optional
877 <a href="#callingconv">calling convention</a>, a return type, an optional
878 <a href="#paramattrs">parameter attribute</a> for the return type, a function
879 name, a (possibly empty) argument list (each with optional
880 <a href="#paramattrs">parameter attributes</a>), optional
881 <a href="#fnattrs">function attributes</a>, an optional section, an optional
882 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
883 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]885<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
886 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]887 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]888 <a href="#callingconv">calling convention</a>, a return type, an optional
889 <a href="#paramattrs">parameter attribute</a> for the return type, a function
890 name, a possibly empty list of arguments, an optional alignment, and an
891 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]893<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]894 (Control Flow Graph) for the function. Each basic block may optionally start
895 with a label (giving the basic block a symbol table entry), contains a list
896 of instructions, and ends with a <a href="#terminators">terminator</a>
897 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898
899<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]900 executed on entrance to the function, and it is not allowed to have
901 predecessor basic blocks (i.e. there can not be any branches to the entry
902 block of a function). Because the block can have no predecessors, it also
903 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]904
905<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]906 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907
908<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]909 the alignment is set to zero, the alignment of the function is set by the
910 target to whatever it feels convenient. If an explicit alignment is
911 specified, the function is forced to have at least that much alignment. All
912 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]913
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]914<h5>Syntax:</h5>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]915<pre class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]916define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]917 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
918 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
919 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
920 [<a href="#gc">gc</a>] { ... }
921</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]923</div>
924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]925<!-- ======================================================================= -->
926<div class="doc_subsection">
927 <a name="aliasstructure">Aliases</a>
928</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]930<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931
932<p>Aliases act as "second name" for the aliasee value (which can be either
933 function, global variable, another alias or bitcast of global value). Aliases
934 may have an optional <a href="#linkage">linkage type</a>, and an
935 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]936
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]937<h5>Syntax:</h5>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]938<pre class="doc_code">
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]939@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]940</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]941
942</div>
943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]944<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]945<div class="doc_subsection">
946 <a name="namedmetadatastructure">Named Metadata</a>
947</div>
948
949<div class="doc_text">
950
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]951<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
952 nodes</a> (but not metadata strings) and null are the only valid operands for
953 a named metadata.</p>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]954
955<h5>Syntax:</h5>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]956<pre class="doc_code">
Dan Gohmanc9e14412010-07-13 19:48:13 +0000[diff] [blame]957; An unnamed metadata node, which is referenced by the named metadata.
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]958!1 = metadata !{metadata !"one"}
Dan Gohmanc9e14412010-07-13 19:48:13 +0000[diff] [blame]959; A named metadata.
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]960!name = !{null, !1}
961</pre>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]962
963</div>
964
965<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]966<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]967
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]968<div class="doc_text">
969
970<p>The return type and each parameter of a function type may have a set of
971 <i>parameter attributes</i> associated with them. Parameter attributes are
972 used to communicate additional information about the result or parameters of
973 a function. Parameter attributes are considered to be part of the function,
974 not of the function type, so functions with different parameter attributes
975 can have the same function type.</p>
976
977<p>Parameter attributes are simple keywords that follow the type specified. If
978 multiple parameter attributes are needed, they are space separated. For
979 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]980
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]981<pre class="doc_code">
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]982declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]983declare i32 @atoi(i8 zeroext)
984declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]985</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]986
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]987<p>Note that any attributes for the function result (<tt>nounwind</tt>,
988 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]989
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]990<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]991
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]992<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]993 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates to the code generator that the parameter or return value
995 should be zero-extended to a 32-bit value by the caller (for a parameter)
996 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]997
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]998 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]999 <dd>This indicates to the code generator that the parameter or return value
1000 should be sign-extended to a 32-bit value by the caller (for a parameter)
1001 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1002
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1003 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1004 <dd>This indicates that this parameter or return value should be treated in a
1005 special target-dependent fashion during while emitting code for a function
1006 call or return (usually, by putting it in a register as opposed to memory,
1007 though some targets use it to distinguish between two different kinds of
1008 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]1009
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1010 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1011 <dd>This indicates that the pointer parameter should really be passed by value
1012 to the function. The attribute implies that a hidden copy of the pointee
1013 is made between the caller and the callee, so the callee is unable to
1014 modify the value in the callee. This attribute is only valid on LLVM
1015 pointer arguments. It is generally used to pass structs and arrays by
1016 value, but is also valid on pointers to scalars. The copy is considered
1017 to belong to the caller not the callee (for example,
1018 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1019 <tt>byval</tt> parameters). This is not a valid attribute for return
1020 values. The byval attribute also supports specifying an alignment with
1021 the align attribute. This has a target-specific effect on the code
1022 generator that usually indicates a desired alignment for the synthesized
1023 stack slot.</dd>
1024
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1025 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates that the pointer parameter specifies the address of a
1027 structure that is the return value of the function in the source program.
1028 This pointer must be guaranteed by the caller to be valid: loads and
1029 stores to the structure may be assumed by the callee to not to trap. This
1030 may only be applied to the first parameter. This is not a valid attribute
1031 for return values. </dd>
1032
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1033 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1034 <dd>This indicates that pointer values
1035 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohman24fc36d2010-07-02 23:46:54 +0000[diff] [blame]1036 value do not alias pointer values which are not <i>based</i> on it,
1037 ignoring certain "irrelevant" dependencies.
1038 For a call to the parent function, dependencies between memory
1039 references from before or after the call and from those during the call
1040 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1041 return value used in that call.
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1042 The caller shares the responsibility with the callee for ensuring that
1043 these requirements are met.
1044 For further details, please see the discussion of the NoAlias response in
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]1045 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1046<br>
John McCall0f56d702010-07-06 21:07:14 +0000[diff] [blame]1047 Note that this definition of <tt>noalias</tt> is intentionally
1048 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattnerd6c58d82010-07-06 20:51:35 +0000[diff] [blame]1049 arguments, though it is slightly weaker.
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]1050<br>
1051 For function return values, C99's <tt>restrict</tt> is not meaningful,
1052 while LLVM's <tt>noalias</tt> is.
1053 </dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1054
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1055 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This indicates that the callee does not make any copies of the pointer
1057 that outlive the callee itself. This is not a valid attribute for return
1058 values.</dd>
1059
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]1060 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This indicates that the pointer parameter can be excised using the
1062 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1063 attribute for return values.</dd>
1064</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1065
1066</div>
1067
1068<!-- ======================================================================= -->
1069<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1070 <a name="gc">Garbage Collector Names</a>
1071</div>
1072
1073<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1074
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1075<p>Each function may specify a garbage collector name, which is simply a
1076 string:</p>
1077
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1078<pre class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1079define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1080</pre>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1081
1082<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1083 collector which will cause the compiler to alter its output in order to
1084 support the named garbage collection algorithm.</p>
1085
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1086</div>
1087
1088<!-- ======================================================================= -->
1089<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1090 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1091</div>
1092
1093<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1094
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1095<p>Function attributes are set to communicate additional information about a
1096 function. Function attributes are considered to be part of the function, not
1097 of the function type, so functions with different parameter attributes can
1098 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1099
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1100<p>Function attributes are simple keywords that follow the type specified. If
1101 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1102
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1103<pre class="doc_code">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1104define void @f() noinline { ... }
1105define void @f() alwaysinline { ... }
1106define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1107define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1108</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1109
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1110<dl>
Charles Davisfaa8f752010-02-12 00:31:15 +0000[diff] [blame]1111 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1112 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1113 the backend should forcibly align the stack pointer. Specify the
1114 desired alignment, which must be a power of two, in parentheses.
1115
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1116 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1117 <dd>This attribute indicates that the inliner should attempt to inline this
1118 function into callers whenever possible, ignoring any active inlining size
1119 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1120
Jakob Stoklund Olesen77180732010-02-06 01:16:28 +0000[diff] [blame]1121 <dt><tt><b>inlinehint</b></tt></dt>
1122 <dd>This attribute indicates that the source code contained a hint that inlining
1123 this function is desirable (such as the "inline" keyword in C/C++). It
1124 is just a hint; it imposes no requirements on the inliner.</dd>
1125
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1126 <dt><tt><b>naked</b></tt></dt>
1127 <dd>This attribute disables prologue / epilogue emission for the function.
1128 This can have very system-specific consequences.</dd>
1129
1130 <dt><tt><b>noimplicitfloat</b></tt></dt>
1131 <dd>This attributes disables implicit floating point instructions.</dd>
1132
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the inliner should never inline this
1135 function in any situation. This attribute may not be used together with
1136 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1137
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1138 <dt><tt><b>noredzone</b></tt></dt>
1139 <dd>This attribute indicates that the code generator should not use a red
1140 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1141
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1142 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1143 <dd>This function attribute indicates that the function never returns
1144 normally. This produces undefined behavior at runtime if the function
1145 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1146
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1147 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1148 <dd>This function attribute indicates that the function never returns with an
1149 unwind or exceptional control flow. If the function does unwind, its
1150 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1151
Nick Lewyckybc036ee2010-07-06 18:24:09 +0000[diff] [blame]1152 <dt><tt><b>optsize</b></tt></dt>
1153 <dd>This attribute suggests that optimization passes and code generator passes
1154 make choices that keep the code size of this function low, and otherwise
1155 do optimizations specifically to reduce code size.</dd>
1156
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1157 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1158 <dd>This attribute indicates that the function computes its result (or decides
1159 to unwind an exception) based strictly on its arguments, without
1160 dereferencing any pointer arguments or otherwise accessing any mutable
1161 state (e.g. memory, control registers, etc) visible to caller functions.
1162 It does not write through any pointer arguments
1163 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1164 changes any state visible to callers. This means that it cannot unwind
1165 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1166 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1167
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1168 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1169 <dd>This attribute indicates that the function does not write through any
1170 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1171 arguments) or otherwise modify any state (e.g. memory, control registers,
1172 etc) visible to caller functions. It may dereference pointer arguments
1173 and read state that may be set in the caller. A readonly function always
1174 returns the same value (or unwinds an exception identically) when called
1175 with the same set of arguments and global state. It cannot unwind an
1176 exception by calling the <tt>C++</tt> exception throwing methods, but may
1177 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1178
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1179 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1180 <dd>This attribute indicates that the function should emit a stack smashing
1181 protector. It is in the form of a "canary"&mdash;a random value placed on
1182 the stack before the local variables that's checked upon return from the
1183 function to see if it has been overwritten. A heuristic is used to
1184 determine if a function needs stack protectors or not.<br>
1185<br>
1186 If a function that has an <tt>ssp</tt> attribute is inlined into a
1187 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1188 function will have an <tt>ssp</tt> attribute.</dd>
1189
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1190 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1191 <dd>This attribute indicates that the function should <em>always</em> emit a
1192 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1193 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1194<br>
1195 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1196 function that doesn't have an <tt>sspreq</tt> attribute or which has
1197 an <tt>ssp</tt> attribute, then the resulting function will have
1198 an <tt>sspreq</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1199</dl>
1200
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1201</div>
1202
1203<!-- ======================================================================= -->
1204<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1205 <a name="moduleasm">Module-Level Inline Assembly</a>
1206</div>
1207
1208<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1209
1210<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1211 the GCC "file scope inline asm" blocks. These blocks are internally
1212 concatenated by LLVM and treated as a single unit, but may be separated in
1213 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1214
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1215<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1216module asm "inline asm code goes here"
1217module asm "more can go here"
1218</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1219
1220<p>The strings can contain any character by escaping non-printable characters.
1221 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1222 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1223
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1224<p>The inline asm code is simply printed to the machine code .s file when
1225 assembly code is generated.</p>
1226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227</div>
1228
1229<!-- ======================================================================= -->
1230<div class="doc_subsection">
1231 <a name="datalayout">Data Layout</a>
1232</div>
1233
1234<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1236<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1237 data is to be laid out in memory. The syntax for the data layout is
1238 simply:</p>
1239
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]1240<pre class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1241target datalayout = "<i>layout specification</i>"
1242</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1243
1244<p>The <i>layout specification</i> consists of a list of specifications
1245 separated by the minus sign character ('-'). Each specification starts with
1246 a letter and may include other information after the letter to define some
1247 aspect of the data layout. The specifications accepted are as follows:</p>
1248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1249<dl>
1250 <dt><tt>E</tt></dt>
1251 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1252 bits with the most significance have the lowest address location.</dd>
1253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1254 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1255 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1256 the bits with the least significance have the lowest address
1257 location.</dd>
1258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1260 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1261 <i>preferred</i> alignments. All sizes are in bits. Specifying
1262 the <i>pref</i> alignment is optional. If omitted, the
1263 preceding <tt>:</tt> should be omitted too.</dd>
1264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1265 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1266 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1267 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1268
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1269 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1270 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1271 <i>size</i>.</dd>
1272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1273 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1274 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesen7dabc4c2010-05-28 18:54:47 +0000[diff] [blame]1275 <i>size</i>. Only values of <i>size</i> that are supported by the target
1276 will work. 32 (float) and 64 (double) are supported on all targets;
1277 80 or 128 (different flavors of long double) are also supported on some
1278 targets.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1280 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1281 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1282 <i>size</i>.</dd>
1283
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1284 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1285 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1286 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1287
1288 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1289 <dd>This specifies a set of native integer widths for the target CPU
1290 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1291 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1292 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1293 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1294</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1296<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]1297 default set of specifications which are then (possibly) overridden by the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1298 specifications in the <tt>datalayout</tt> keyword. The default specifications
1299 are given in this list:</p>
1300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1301<ul>
1302 <li><tt>E</tt> - big endian</li>
Dan Gohmane78194f2010-02-23 02:44:03 +0000[diff] [blame]1303 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1304 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1305 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1306 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1307 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1308 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1309 alignment of 64-bits</li>
1310 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1311 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1312 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1313 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1314 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1315 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1316</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1317
1318<p>When LLVM is determining the alignment for a given type, it uses the
1319 following rules:</p>
1320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1321<ol>
1322 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1323 specification is used.</li>
1324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1325 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1326 smallest integer type that is larger than the bitwidth of the sought type
1327 is used. If none of the specifications are larger than the bitwidth then
1328 the the largest integer type is used. For example, given the default
1329 specifications above, the i7 type will use the alignment of i8 (next
1330 largest) while both i65 and i256 will use the alignment of i64 (largest
1331 specified).</li>
1332
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1333 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1334 largest vector type that is smaller than the sought vector type will be
1335 used as a fall back. This happens because &lt;128 x double&gt; can be
1336 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1339</div>
1340
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1341<!-- ======================================================================= -->
1342<div class="doc_subsection">
1343 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1344</div>
1345
1346<div class="doc_text">
1347
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1348<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1349with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1350is undefined. Pointer values are associated with address ranges
1351according to the following rules:</p>
1352
1353<ul>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1354 <li>A pointer value is associated with the addresses associated with
1355 any value it is <i>based</i> on.
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1356 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1357 range of the variable's storage.</li>
1358 <li>The result value of an allocation instruction is associated with
1359 the address range of the allocated storage.</li>
1360 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1361 no address.</li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1362 <li>An integer constant other than zero or a pointer value returned
1363 from a function not defined within LLVM may be associated with address
1364 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1365 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1366 allocated by mechanisms provided by LLVM.</li>
Dan Gohmanc8208442010-07-02 18:41:32 +0000[diff] [blame]1367</ul>
1368
1369<p>A pointer value is <i>based</i> on another pointer value according
1370 to the following rules:</p>
1371
1372<ul>
1373 <li>A pointer value formed from a
1374 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1375 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1376 <li>The result value of a
1377 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1378 of the <tt>bitcast</tt>.</li>
1379 <li>A pointer value formed by an
1380 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1381 pointer values that contribute (directly or indirectly) to the
1382 computation of the pointer's value.</li>
1383 <li>The "<i>based</i> on" relationship is transitive.</li>
1384</ul>
1385
1386<p>Note that this definition of <i>"based"</i> is intentionally
1387 similar to the definition of <i>"based"</i> in C99, though it is
1388 slightly weaker.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1389
1390<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1391<tt><a href="#i_load">load</a></tt> merely indicates the size and
1392alignment of the memory from which to load, as well as the
Dan Gohmand72730e2010-06-17 19:23:50 +0000[diff] [blame]1393interpretation of the value. The first operand type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1394<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1395and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1396
1397<p>Consequently, type-based alias analysis, aka TBAA, aka
1398<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1399LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1400additional information which specialized optimization passes may use
1401to implement type-based alias analysis.</p>
1402
1403</div>
1404
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]1405<!-- ======================================================================= -->
1406<div class="doc_subsection">
1407 <a name="volatile">Volatile Memory Accesses</a>
1408</div>
1409
1410<div class="doc_text">
1411
1412<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1413href="#i_store"><tt>store</tt></a>s, and <a
1414href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1415The optimizers must not change the number of volatile operations or change their
1416order of execution relative to other volatile operations. The optimizers
1417<i>may</i> change the order of volatile operations relative to non-volatile
1418operations. This is not Java's "volatile" and has no cross-thread
1419synchronization behavior.</p>
1420
1421</div>
1422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1423<!-- *********************************************************************** -->
1424<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1425<!-- *********************************************************************** -->
1426
1427<div class="doc_text">
1428
1429<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1430 intermediate representation. Being typed enables a number of optimizations
1431 to be performed on the intermediate representation directly, without having
1432 to do extra analyses on the side before the transformation. A strong type
1433 system makes it easier to read the generated code and enables novel analyses
1434 and transformations that are not feasible to perform on normal three address
1435 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1436
1437</div>
1438
1439<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1440<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1441Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1443<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1444
1445<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1446
1447<table border="1" cellspacing="0" cellpadding="4">
1448 <tbody>
1449 <tr><th>Classification</th><th>Types</th></tr>
1450 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1451 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1452 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1453 </tr>
1454 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1455 <td><a href="#t_floating">floating point</a></td>
1456 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1457 </tr>
1458 <tr>
1459 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1460 <td><a href="#t_integer">integer</a>,
1461 <a href="#t_floating">floating point</a>,
1462 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1463 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1464 <a href="#t_struct">structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1465 <a href="#t_union">union</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1466 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1467 <a href="#t_label">label</a>,
1468 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1469 </td>
1470 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1471 <tr>
1472 <td><a href="#t_primitive">primitive</a></td>
1473 <td><a href="#t_label">label</a>,
1474 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1475 <a href="#t_floating">floating point</a>,
1476 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1477 </tr>
1478 <tr>
1479 <td><a href="#t_derived">derived</a></td>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1480 <td><a href="#t_array">array</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1481 <a href="#t_function">function</a>,
1482 <a href="#t_pointer">pointer</a>,
1483 <a href="#t_struct">structure</a>,
1484 <a href="#t_pstruct">packed structure</a>,
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1485 <a href="#t_union">union</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1486 <a href="#t_vector">vector</a>,
1487 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1488 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1489 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1490 </tbody>
1491</table>
1492
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1493<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1494 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1495 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1497</div>
1498
1499<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1500<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1501
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1502<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1503
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1504<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1505 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1506
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1507</div>
1508
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1509<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1510<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1511
1512<div class="doc_text">
1513
1514<h5>Overview:</h5>
1515<p>The integer type is a very simple type that simply specifies an arbitrary
1516 bit width for the integer type desired. Any bit width from 1 bit to
1517 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1518
1519<h5>Syntax:</h5>
1520<pre>
1521 iN
1522</pre>
1523
1524<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1525 value.</p>
1526
1527<h5>Examples:</h5>
1528<table class="layout">
1529 <tr class="layout">
1530 <td class="left"><tt>i1</tt></td>
1531 <td class="left">a single-bit integer.</td>
1532 </tr>
1533 <tr class="layout">
1534 <td class="left"><tt>i32</tt></td>
1535 <td class="left">a 32-bit integer.</td>
1536 </tr>
1537 <tr class="layout">
1538 <td class="left"><tt>i1942652</tt></td>
1539 <td class="left">a really big integer of over 1 million bits.</td>
1540 </tr>
1541</table>
1542
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1543</div>
1544
1545<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1546<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1547
1548<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1549
1550<table>
1551 <tbody>
1552 <tr><th>Type</th><th>Description</th></tr>
1553 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1554 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1555 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1556 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1557 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1558 </tbody>
1559</table>
1560
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1561</div>
1562
1563<!-- _______________________________________________________________________ -->
1564<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1565
1566<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1567
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1568<h5>Overview:</h5>
1569<p>The void type does not represent any value and has no size.</p>
1570
1571<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1572<pre>
1573 void
1574</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1575
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1576</div>
1577
1578<!-- _______________________________________________________________________ -->
1579<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1580
1581<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1582
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1583<h5>Overview:</h5>
1584<p>The label type represents code labels.</p>
1585
1586<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1587<pre>
1588 label
1589</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1590
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1591</div>
1592
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1593<!-- _______________________________________________________________________ -->
1594<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1595
1596<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1597
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1598<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1599<p>The metadata type represents embedded metadata. No derived types may be
1600 created from metadata except for <a href="#t_function">function</a>
1601 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1602
1603<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1604<pre>
1605 metadata
1606</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1607
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1608</div>
1609
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1610
1611<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1612<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1613
1614<div class="doc_text">
1615
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1616<p>The real power in LLVM comes from the derived types in the system. This is
1617 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1618 useful types. Each of these types contain one or more element types which
1619 may be a primitive type, or another derived type. For example, it is
1620 possible to have a two dimensional array, using an array as the element type
1621 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1622
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1623
1624</div>
1625
1626<!-- _______________________________________________________________________ -->
1627<div class="doc_subsubsection"> <a name="t_aggregate">Aggregate Types</a> </div>
1628
1629<div class="doc_text">
1630
1631<p>Aggregate Types are a subset of derived types that can contain multiple
1632 member types. <a href="#t_array">Arrays</a>,
1633 <a href="#t_struct">structs</a>, <a href="#t_vector">vectors</a> and
1634 <a href="#t_union">unions</a> are aggregate types.</p>
1635
1636</div>
1637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1638<!-- _______________________________________________________________________ -->
1639<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1640
1641<div class="doc_text">
1642
1643<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1645 sequentially in memory. The array type requires a size (number of elements)
1646 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1647
1648<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649<pre>
1650 [&lt;# elements&gt; x &lt;elementtype&gt;]
1651</pre>
1652
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1653<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1654 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1655
1656<h5>Examples:</h5>
1657<table class="layout">
1658 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1659 <td class="left"><tt>[40 x i32]</tt></td>
1660 <td class="left">Array of 40 32-bit integer values.</td>
1661 </tr>
1662 <tr class="layout">
1663 <td class="left"><tt>[41 x i32]</tt></td>
1664 <td class="left">Array of 41 32-bit integer values.</td>
1665 </tr>
1666 <tr class="layout">
1667 <td class="left"><tt>[4 x i8]</tt></td>
1668 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1669 </tr>
1670</table>
1671<p>Here are some examples of multidimensional arrays:</p>
1672<table class="layout">
1673 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1674 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1675 <td class="left">3x4 array of 32-bit integer values.</td>
1676 </tr>
1677 <tr class="layout">
1678 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1679 <td class="left">12x10 array of single precision floating point values.</td>
1680 </tr>
1681 <tr class="layout">
1682 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1683 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1684 </tr>
1685</table>
1686
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1687<p>There is no restriction on indexing beyond the end of the array implied by
1688 a static type (though there are restrictions on indexing beyond the bounds
1689 of an allocated object in some cases). This means that single-dimension
1690 'variable sized array' addressing can be implemented in LLVM with a zero
1691 length array type. An implementation of 'pascal style arrays' in LLVM could
1692 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1693
1694</div>
1695
1696<!-- _______________________________________________________________________ -->
1697<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1698
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1699<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1701<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1702<p>The function type can be thought of as a function signature. It consists of
1703 a return type and a list of formal parameter types. The return type of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1704 function type is a scalar type, a void type, a struct type, or a union
1705 type. If the return type is a struct type then all struct elements must be
1706 of first class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1707
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1708<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1709<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1710 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1711</pre>
1712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1713<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1714 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1715 which indicates that the function takes a variable number of arguments.
1716 Variable argument functions can access their arguments with
1717 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1718 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1719 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1721<h5>Examples:</h5>
1722<table class="layout">
1723 <tr class="layout">
1724 <td class="left"><tt>i32 (i32)</tt></td>
1725 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1726 </td>
1727 </tr><tr class="layout">
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1728 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1729 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1730 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]1731 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
1732 returning <tt>float</tt>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1733 </td>
1734 </tr><tr class="layout">
1735 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1736 <td class="left">A vararg function that takes at least one
1737 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1738 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1739 LLVM.
1740 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1741 </tr><tr class="layout">
1742 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1743 <td class="left">A function taking an <tt>i32</tt>, returning a
1744 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1745 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1746 </tr>
1747</table>
1748
1749</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1751<!-- _______________________________________________________________________ -->
1752<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1754<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1756<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1757<p>The structure type is used to represent a collection of data members together
1758 in memory. The packing of the field types is defined to match the ABI of the
1759 underlying processor. The elements of a structure may be any type that has a
1760 size.</p>
1761
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1762<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1763 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1764 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1765 Structures in registers are accessed using the
1766 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1767 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1769<pre>
1770 { &lt;type list&gt; }
1771</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1773<h5>Examples:</h5>
1774<table class="layout">
1775 <tr class="layout">
1776 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1777 <td class="left">A triple of three <tt>i32</tt> values</td>
1778 </tr><tr class="layout">
1779 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1780 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1781 second element is a <a href="#t_pointer">pointer</a> to a
1782 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1783 an <tt>i32</tt>.</td>
1784 </tr>
1785</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1786
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1787</div>
1788
1789<!-- _______________________________________________________________________ -->
1790<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1791</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1792
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1793<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1795<h5>Overview:</h5>
1796<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1797 together in memory. There is no padding between fields. Further, the
1798 alignment of a packed structure is 1 byte. The elements of a packed
1799 structure may be any type that has a size.</p>
1800
1801<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1802 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1803 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1805<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1806<pre>
1807 &lt; { &lt;type list&gt; } &gt;
1808</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1810<h5>Examples:</h5>
1811<table class="layout">
1812 <tr class="layout">
1813 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1814 <td class="left">A triple of three <tt>i32</tt> values</td>
1815 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1816 <td class="left">
1817<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1818 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1819 second element is a <a href="#t_pointer">pointer</a> to a
1820 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1821 an <tt>i32</tt>.</td>
1822 </tr>
1823</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825</div>
1826
1827<!-- _______________________________________________________________________ -->
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1828<div class="doc_subsubsection"> <a name="t_union">Union Type</a> </div>
1829
1830<div class="doc_text">
1831
1832<h5>Overview:</h5>
1833<p>A union type describes an object with size and alignment suitable for
1834 an object of any one of a given set of types (also known as an "untagged"
1835 union). It is similar in concept and usage to a
1836 <a href="#t_struct">struct</a>, except that all members of the union
1837 have an offset of zero. The elements of a union may be any type that has a
1838 size. Unions must have at least one member - empty unions are not allowed.
1839 </p>
1840
1841<p>The size of the union as a whole will be the size of its largest member,
1842 and the alignment requirements of the union as a whole will be the largest
1843 alignment requirement of any member.</p>
1844
Dan Gohmanef8400c2010-02-25 16:51:31 +0000[diff] [blame]1845<p>Union members are accessed using '<tt><a href="#i_load">load</a></tt> and
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]1846 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1847 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1848 Since all members are at offset zero, the getelementptr instruction does
1849 not affect the address, only the type of the resulting pointer.</p>
1850
1851<h5>Syntax:</h5>
1852<pre>
1853 union { &lt;type list&gt; }
1854</pre>
1855
1856<h5>Examples:</h5>
1857<table class="layout">
1858 <tr class="layout">
1859 <td class="left"><tt>union { i32, i32*, float }</tt></td>
1860 <td class="left">A union of three types: an <tt>i32</tt>, a pointer to
1861 an <tt>i32</tt>, and a <tt>float</tt>.</td>
1862 </tr><tr class="layout">
1863 <td class="left">
1864 <tt>union {&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1865 <td class="left">A union, where the first element is a <tt>float</tt> and the
1866 second element is a <a href="#t_pointer">pointer</a> to a
1867 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1868 an <tt>i32</tt>.</td>
1869 </tr>
1870</table>
1871
1872</div>
1873
1874<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1875<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1876
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1877<div class="doc_text">
1878
1879<h5>Overview:</h5>
Dan Gohmanb2f72c82010-02-25 16:50:07 +0000[diff] [blame]1880<p>The pointer type is used to specify memory locations.
1881 Pointers are commonly used to reference objects in memory.</p>
1882
1883<p>Pointer types may have an optional address space attribute defining the
1884 numbered address space where the pointed-to object resides. The default
1885 address space is number zero. The semantics of non-zero address
1886 spaces are target-specific.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1887
1888<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1889 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1891<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1892<pre>
1893 &lt;type&gt; *
1894</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1896<h5>Examples:</h5>
1897<table class="layout">
1898 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1899 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1900 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1901 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1902 </tr>
1903 <tr class="layout">
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]1904 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1905 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1906 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1907 <tt>i32</tt>.</td>
1908 </tr>
1909 <tr class="layout">
1910 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1911 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1912 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1913 </tr>
1914</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1916</div>
1917
1918<!-- _______________________________________________________________________ -->
1919<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1921<div class="doc_text">
1922
1923<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1924<p>A vector type is a simple derived type that represents a vector of elements.
1925 Vector types are used when multiple primitive data are operated in parallel
1926 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1927 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1928 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1929
1930<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1931<pre>
1932 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1933</pre>
1934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1935<p>The number of elements is a constant integer value; elementtype may be any
1936 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1937
1938<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1939<table class="layout">
1940 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1941 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1942 <td class="left">Vector of 4 32-bit integer values.</td>
1943 </tr>
1944 <tr class="layout">
1945 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1946 <td class="left">Vector of 8 32-bit floating-point values.</td>
1947 </tr>
1948 <tr class="layout">
1949 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1950 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1951 </tr>
1952</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1954</div>
1955
1956<!-- _______________________________________________________________________ -->
1957<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1958<div class="doc_text">
1959
1960<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1961<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1962 corresponds (for example) to the C notion of a forward declared structure
1963 type. In LLVM, opaque types can eventually be resolved to any type (not just
1964 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1965
1966<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967<pre>
1968 opaque
1969</pre>
1970
1971<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1972<table class="layout">
1973 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1974 <td class="left"><tt>opaque</tt></td>
1975 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1976 </tr>
1977</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1979</div>
1980
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1981<!-- ======================================================================= -->
1982<div class="doc_subsection">
1983 <a name="t_uprefs">Type Up-references</a>
1984</div>
1985
1986<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1987
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1988<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1989<p>An "up reference" allows you to refer to a lexically enclosing type without
1990 requiring it to have a name. For instance, a structure declaration may
1991 contain a pointer to any of the types it is lexically a member of. Example
1992 of up references (with their equivalent as named type declarations)
1993 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1994
1995<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1996 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1997 { \2 }* %y = type { %y }*
1998 \1* %z = type %z*
1999</pre>
2000
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2001<p>An up reference is needed by the asmprinter for printing out cyclic types
2002 when there is no declared name for a type in the cycle. Because the
2003 asmprinter does not want to print out an infinite type string, it needs a
2004 syntax to handle recursive types that have no names (all names are optional
2005 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2006
2007<h5>Syntax:</h5>
2008<pre>
2009 \&lt;level&gt;
2010</pre>
2011
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2012<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2013
2014<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2015<table class="layout">
2016 <tr class="layout">
2017 <td class="left"><tt>\1*</tt></td>
2018 <td class="left">Self-referential pointer.</td>
2019 </tr>
2020 <tr class="layout">
2021 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
2022 <td class="left">Recursive structure where the upref refers to the out-most
2023 structure.</td>
2024 </tr>
2025</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]2026
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2027</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2028
2029<!-- *********************************************************************** -->
2030<div class="doc_section"> <a name="constants">Constants</a> </div>
2031<!-- *********************************************************************** -->
2032
2033<div class="doc_text">
2034
2035<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2036 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2037
2038</div>
2039
2040<!-- ======================================================================= -->
2041<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
2042
2043<div class="doc_text">
2044
2045<dl>
2046 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2047 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]2048 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2049
2050 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2051 <dd>Standard integers (such as '4') are constants of
2052 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2053 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2054
2055 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2056 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2057 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2058 notation (see below). The assembler requires the exact decimal value of a
2059 floating-point constant. For example, the assembler accepts 1.25 but
2060 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2061 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2062
2063 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2064 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2065 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2066</dl>
2067
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2068<p>The one non-intuitive notation for constants is the hexadecimal form of
2069 floating point constants. For example, the form '<tt>double
2070 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2071 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2072 constants are required (and the only time that they are generated by the
2073 disassembler) is when a floating point constant must be emitted but it cannot
2074 be represented as a decimal floating point number in a reasonable number of
2075 digits. For example, NaN's, infinities, and other special values are
2076 represented in their IEEE hexadecimal format so that assembly and disassembly
2077 do not cause any bits to change in the constants.</p>
2078
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]2079<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2080 represented using the 16-digit form shown above (which matches the IEEE754
2081 representation for double); float values must, however, be exactly
2082 representable as IEE754 single precision. Hexadecimal format is always used
2083 for long double, and there are three forms of long double. The 80-bit format
2084 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2085 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2086 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2087 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2088 currently supported target uses this format. Long doubles will only work if
2089 they match the long double format on your target. All hexadecimal formats
2090 are big-endian (sign bit at the left).</p>
2091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2092</div>
2093
2094<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2095<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2096<a name="aggregateconstants"></a> <!-- old anchor -->
2097<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2098</div>
2099
2100<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2101
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]2102<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2103 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2104
2105<dl>
2106 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2107 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2108 type definitions (a comma separated list of elements, surrounded by braces
2109 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2110 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2111 Structure constants must have <a href="#t_struct">structure type</a>, and
2112 the number and types of elements must match those specified by the
2113 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2114
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2115 <dt><b>Union constants</b></dt>
2116 <dd>Union constants are represented with notation similar to a structure with
2117 a single element - that is, a single typed element surrounded
2118 by braces (<tt>{}</tt>)). For example: "<tt>{ i32 4 }</tt>". The
2119 <a href="#t_union">union type</a> can be initialized with a single-element
2120 struct as long as the type of the struct element matches the type of
2121 one of the union members.</dd>
2122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2123 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2124 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2125 definitions (a comma separated list of elements, surrounded by square
2126 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2127 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2128 the number and types of elements must match those specified by the
2129 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2130
2131 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2132 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2133 definitions (a comma separated list of elements, surrounded by
2134 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2135 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2136 have <a href="#t_vector">vector type</a>, and the number and types of
2137 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2138
2139 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2140 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]2141 value to zero of <em>any</em> type, including scalar and
2142 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2143 This is often used to avoid having to print large zero initializers
2144 (e.g. for large arrays) and is always exactly equivalent to using explicit
2145 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2146
2147 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2148 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2149 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2150 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2151 be interpreted as part of the instruction stream, metadata is a place to
2152 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2153</dl>
2154
2155</div>
2156
2157<!-- ======================================================================= -->
2158<div class="doc_subsection">
2159 <a name="globalconstants">Global Variable and Function Addresses</a>
2160</div>
2161
2162<div class="doc_text">
2163
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2164<p>The addresses of <a href="#globalvars">global variables</a>
2165 and <a href="#functionstructure">functions</a> are always implicitly valid
2166 (link-time) constants. These constants are explicitly referenced when
2167 the <a href="#identifiers">identifier for the global</a> is used and always
2168 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2169 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2170
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2171<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2172@X = global i32 17
2173@Y = global i32 42
2174@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2175</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2176
2177</div>
2178
2179<!-- ======================================================================= -->
2180<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2181<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2182
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2183<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2184 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2185 Undefined values may be of any type (other than label or void) and be used
2186 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2187
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2188<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2189 program is well defined no matter what value is used. This gives the
2190 compiler more freedom to optimize. Here are some examples of (potentially
2191 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2192
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2193
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2194<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2195 %A = add %X, undef
2196 %B = sub %X, undef
2197 %C = xor %X, undef
2198Safe:
2199 %A = undef
2200 %B = undef
2201 %C = undef
2202</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2203
2204<p>This is safe because all of the output bits are affected by the undef bits.
2205Any output bit can have a zero or one depending on the input bits.</p>
2206
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2207<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2208 %A = or %X, undef
2209 %B = and %X, undef
2210Safe:
2211 %A = -1
2212 %B = 0
2213Unsafe:
2214 %A = undef
2215 %B = undef
2216</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2217
2218<p>These logical operations have bits that are not always affected by the input.
2219For example, if "%X" has a zero bit, then the output of the 'and' operation will
2220always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2221such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2222However, it is safe to assume that all bits of the undef could be 0, and
2223optimize the and to 0. Likewise, it is safe to assume that all the bits of
2224the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2225-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2226
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2227<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2228 %A = select undef, %X, %Y
2229 %B = select undef, 42, %Y
2230 %C = select %X, %Y, undef
2231Safe:
2232 %A = %X (or %Y)
2233 %B = 42 (or %Y)
2234 %C = %Y
2235Unsafe:
2236 %A = undef
2237 %B = undef
2238 %C = undef
2239</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2240
2241<p>This set of examples show that undefined select (and conditional branch)
2242conditions can go "either way" but they have to come from one of the two
2243operands. In the %A example, if %X and %Y were both known to have a clear low
2244bit, then %A would have to have a cleared low bit. However, in the %C example,
2245the optimizer is allowed to assume that the undef operand could be the same as
2246%Y, allowing the whole select to be eliminated.</p>
2247
2248
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2249<pre class="doc_code">
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2250 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2251
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2252 %B = undef
2253 %C = xor %B, %B
2254
2255 %D = undef
2256 %E = icmp lt %D, 4
2257 %F = icmp gte %D, 4
2258
2259Safe:
2260 %A = undef
2261 %B = undef
2262 %C = undef
2263 %D = undef
2264 %E = undef
2265 %F = undef
2266</pre>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2267
2268<p>This example points out that two undef operands are not necessarily the same.
2269This can be surprising to people (and also matches C semantics) where they
2270assume that "X^X" is always zero, even if X is undef. This isn't true for a
2271number of reasons, but the short answer is that an undef "variable" can
2272arbitrarily change its value over its "live range". This is true because the
2273"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2274logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2275so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2276to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2277would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2278
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2279<pre class="doc_code">
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2280 %A = fdiv undef, %X
2281 %B = fdiv %X, undef
2282Safe:
2283 %A = undef
2284b: unreachable
2285</pre>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2286
2287<p>These examples show the crucial difference between an <em>undefined
2288value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2289allowed to have an arbitrary bit-pattern. This means that the %A operation
2290can be constant folded to undef because the undef could be an SNaN, and fdiv is
2291not (currently) defined on SNaN's. However, in the second example, we can make
2292a more aggressive assumption: because the undef is allowed to be an arbitrary
2293value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner83d45d72009-09-08 19:45:34 +0000[diff] [blame]2294has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2295does not execute at all. This allows us to delete the divide and all code after
2296it: since the undefined operation "can't happen", the optimizer can assume that
2297it occurs in dead code.
2298</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2299
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2300<pre class="doc_code">
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2301a: store undef -> %X
2302b: store %X -> undef
2303Safe:
2304a: &lt;deleted&gt;
2305b: unreachable
2306</pre>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2307
2308<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2309can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2310overwritten with bits that happen to match what was already there. However, a
2311store "to" an undefined location could clobber arbitrary memory, therefore, it
2312has undefined behavior.</p>
2313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2314</div>
2315
2316<!-- ======================================================================= -->
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2317<div class="doc_subsection"><a name="trapvalues">Trap Values</a></div>
2318<div class="doc_text">
2319
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2320<p>Trap values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2321 instead of representing an unspecified bit pattern, they represent the
2322 fact that an instruction or constant expression which cannot evoke side
2323 effects has nevertheless detected a condition which results in undefined
Dan Gohman67bf37f2010-04-26 20:21:21 +0000[diff] [blame]2324 behavior.</p>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2325
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2326<p>There is currently no way of representing a trap value in the IR; they
Dan Gohmanc4bfe502010-05-03 14:51:43 +0000[diff] [blame]2327 only exist when produced by operations such as
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2328 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2329
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2330<p>Trap value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2331
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2332<ul>
2333<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2334 their operands.</li>
2335
2336<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2337 to their dynamic predecessor basic block.</li>
2338
2339<li>Function arguments depend on the corresponding actual argument values in
2340 the dynamic callers of their functions.</li>
2341
2342<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2343 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2344 control back to them.</li>
2345
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame]2346<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
2347 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_unwind"><tt>unwind</tt></a>,
2348 or exception-throwing call instructions that dynamically transfer control
2349 back to them.</li>
2350
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2351<li>Non-volatile loads and stores depend on the most recent stores to all of the
2352 referenced memory addresses, following the order in the IR
2353 (including loads and stores implied by intrinsics such as
2354 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2355
Dan Gohmane2c06b62010-05-03 14:59:34 +0000[diff] [blame]2356<!-- TODO: In the case of multiple threads, this only applies if the store
2357 "happens-before" the load or store. -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2358
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2359<!-- TODO: floating-point exception state -->
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2360
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2361<li>An instruction with externally visible side effects depends on the most
2362 recent preceding instruction with externally visible side effects, following
Dan Gohman8c6704c2010-07-06 15:26:33 +0000[diff] [blame]2363 the order in the IR. (This includes
2364 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2365
Dan Gohman5e7b8fb2010-05-03 14:55:22 +0000[diff] [blame]2366<li>An instruction <i>control-depends</i> on a
2367 <a href="#terminators">terminator instruction</a>
2368 if the terminator instruction has multiple successors and the instruction
2369 is always executed when control transfers to one of the successors, and
2370 may not be executed when control is transfered to another.</li>
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2371
2372<li>Dependence is transitive.</li>
2373
2374</ul>
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2375
2376<p>Whenever a trap value is generated, all values which depend on it evaluate
2377 to trap. If they have side effects, the evoke their side effects as if each
2378 operand with a trap value were undef. If they have externally-visible side
2379 effects, the behavior is undefined.</p>
2380
2381<p>Here are some examples:</p>
Dan Gohman54884272010-04-26 20:54:53 +0000[diff] [blame]2382
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2383<pre class="doc_code">
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2384entry:
2385 %trap = sub nuw i32 0, 1 ; Results in a trap value.
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2386 %still_trap = and i32 %trap, 0 ; Whereas (and i32 undef, 0) would return 0.
2387 %trap_yet_again = getelementptr i32* @h, i32 %still_trap
2388 store i32 0, i32* %trap_yet_again ; undefined behavior
2389
2390 store i32 %trap, i32* @g ; Trap value conceptually stored to memory.
2391 %trap2 = load i32* @g ; Returns a trap value, not just undef.
2392
2393 volatile store i32 %trap, i32* @g ; External observation; undefined behavior.
2394
2395 %narrowaddr = bitcast i32* @g to i16*
2396 %wideaddr = bitcast i32* @g to i64*
2397 %trap3 = load 16* %narrowaddr ; Returns a trap value.
2398 %trap4 = load i64* %widaddr ; Returns a trap value.
2399
2400 %cmp = icmp i32 slt %trap, 0 ; Returns a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2401 %br i1 %cmp, %true, %end ; Branch to either destination.
2402
2403true:
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2404 volatile store i32 0, i32* @g ; This is control-dependent on %cmp, so
2405 ; it has undefined behavior.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2406 br label %end
2407
2408end:
2409 %p = phi i32 [ 0, %entry ], [ 1, %true ]
2410 ; Both edges into this PHI are
2411 ; control-dependent on %cmp, so this
Dan Gohman762c0362010-04-28 00:49:41 +0000[diff] [blame]2412 ; always results in a trap value.
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2413
2414 volatile store i32 0, i32* @g ; %end is control-equivalent to %entry
2415 ; so this is defined (ignoring earlier
2416 ; undefined behavior in this example).
Dan Gohman568ca042010-04-26 23:36:52 +0000[diff] [blame]2417</pre>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2418
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]2419</div>
2420
2421<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2422<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2423 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2424<div class="doc_text">
2425
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2426<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2427
2428<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2429 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2430 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2431
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2432<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2433 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2434 against null. Pointer equality tests between labels addresses is undefined
2435 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2436 equal to the null pointer. This may also be passed around as an opaque
2437 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2438 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2439 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2440
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2441<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2442 using the value as the operand to an inline assembly, but that is target
2443 specific.
2444 </p>
2445
2446</div>
2447
2448
2449<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2450<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2451</div>
2452
2453<div class="doc_text">
2454
2455<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2456 to be used as constants. Constant expressions may be of
2457 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2458 operation that does not have side effects (e.g. load and call are not
2459 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460
2461<dl>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2462 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2463 <dd>Truncate a constant to another type. The bit size of CST must be larger
2464 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2465
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2466 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2467 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsced0daf2010-07-13 12:06:14 +0000[diff] [blame]2468 smaller than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2469
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2470 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2471 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsced0daf2010-07-13 12:06:14 +0000[diff] [blame]2472 smaller than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2473
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2474 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2475 <dd>Truncate a floating point constant to another floating point type. The
2476 size of CST must be larger than the size of TYPE. Both types must be
2477 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2479 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2480 <dd>Floating point extend a constant to another type. The size of CST must be
2481 smaller or equal to the size of TYPE. Both types must be floating
2482 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2483
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2484 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2485 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2486 constant. TYPE must be a scalar or vector integer type. CST must be of
2487 scalar or vector floating point type. Both CST and TYPE must be scalars,
2488 or vectors of the same number of elements. If the value won't fit in the
2489 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2490
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2491 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2493 constant. TYPE must be a scalar or vector integer type. CST must be of
2494 scalar or vector floating point type. Both CST and TYPE must be scalars,
2495 or vectors of the same number of elements. If the value won't fit in the
2496 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2497
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2498 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2500 constant. TYPE must be a scalar or vector floating point type. CST must be
2501 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2502 vectors of the same number of elements. If the value won't fit in the
2503 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2504
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2505 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2507 constant. TYPE must be a scalar or vector floating point type. CST must be
2508 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2509 vectors of the same number of elements. If the value won't fit in the
2510 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2511
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2512 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2513 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2514 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2515 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2516 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2518 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2519 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2520 type. CST must be of integer type. The CST value is zero extended,
2521 truncated, or unchanged to make it fit in a pointer size. This one is
2522 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2523
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2524 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2525 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2526 are the same as those for the <a href="#i_bitcast">bitcast
2527 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2528
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2529 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2530 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2531 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2532 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2533 instruction, the index list may have zero or more indexes, which are
2534 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2536 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2537 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2539 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2541
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2542 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2544
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2545 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2546 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2547 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2549 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2550 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2551 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2553 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2554 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2555 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556
Nick Lewyckyeb94e312010-05-29 06:44:15 +0000[diff] [blame]2557 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2558 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2559 constants. The index list is interpreted in a similar manner as indices in
2560 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2561 index value must be specified.</dd>
2562
2563 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2564 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2565 constants. The index list is interpreted in a similar manner as indices in
2566 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2567 index value must be specified.</dd>
2568
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]2569 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2570 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2571 be any of the <a href="#binaryops">binary</a>
2572 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2573 on operands are the same as those for the corresponding instruction
2574 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577</div>
2578
2579<!-- *********************************************************************** -->
2580<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2581<!-- *********************************************************************** -->
2582
2583<!-- ======================================================================= -->
2584<div class="doc_subsection">
2585<a name="inlineasm">Inline Assembler Expressions</a>
2586</div>
2587
2588<div class="doc_text">
2589
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2590<p>LLVM supports inline assembler expressions (as opposed
2591 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2592 a special value. This value represents the inline assembler as a string
2593 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2594 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2595 expression has side effects, and a flag indicating whether the function
2596 containing the asm needs to align its stack conservatively. An example
2597 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2599<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600i32 (i32) asm "bswap $0", "=r,r"
2601</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2603<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2604 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2605 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2606
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2607<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2609</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2610
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2611<p>Inline asms with side effects not visible in the constraint list must be
2612 marked as having side effects. This is done through the use of the
2613 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2615<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616call void asm sideeffect "eieio", ""()
2617</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2619<p>In some cases inline asms will contain code that will not work unless the
2620 stack is aligned in some way, such as calls or SSE instructions on x86,
2621 yet will not contain code that does that alignment within the asm.
2622 The compiler should make conservative assumptions about what the asm might
2623 contain and should generate its usual stack alignment code in the prologue
2624 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2625
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2626<pre class="doc_code">
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2627call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2628</pre>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2629
2630<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2631 first.</p>
2632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2634 documented here. Constraints on what can be done (e.g. duplication, moving,
2635 etc need to be documented). This is probably best done by reference to
2636 another document that covers inline asm from a holistic perspective.</p>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2637</div>
2638
2639<div class="doc_subsubsection">
2640<a name="inlineasm_md">Inline Asm Metadata</a>
2641</div>
2642
2643<div class="doc_text">
2644
2645<p>The call instructions that wrap inline asm nodes may have a "!srcloc" MDNode
2646 attached to it that contains a constant integer. If present, the code
2647 generator will use the integer as the location cookie value when report
2648 errors through the LLVMContext error reporting mechanisms. This allows a
Dan Gohmanfde3cd72010-04-28 00:36:01 +0000[diff] [blame]2649 front-end to correlate backend errors that occur with inline asm back to the
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2650 source code that produced it. For example:</p>
2651
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2652<pre class="doc_code">
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2653call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2654...
2655!42 = !{ i32 1234567 }
2656</pre>
Chris Lattnerbafc8372010-04-07 05:38:05 +0000[diff] [blame]2657
2658<p>It is up to the front-end to make sense of the magic numbers it places in the
2659 IR.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660
2661</div>
2662
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2663<!-- ======================================================================= -->
2664<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata
2665 Strings</a>
2666</div>
2667
2668<div class="doc_text">
2669
2670<p>LLVM IR allows metadata to be attached to instructions in the program that
2671 can convey extra information about the code to the optimizers and code
2672 generator. One example application of metadata is source-level debug
2673 information. There are two metadata primitives: strings and nodes. All
2674 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2675 preceding exclamation point ('<tt>!</tt>').</p>
2676
2677<p>A metadata string is a string surrounded by double quotes. It can contain
2678 any character by escaping non-printable characters with "\xx" where "xx" is
2679 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
2680
2681<p>Metadata nodes are represented with notation similar to structure constants
2682 (a comma separated list of elements, surrounded by braces and preceded by an
2683 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2684 10}</tt>". Metadata nodes can have any values as their operand.</p>
2685
2686<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2687 metadata nodes, which can be looked up in the module symbol table. For
2688 example: "<tt>!foo = metadata !{!4, !3}</tt>".
2689
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2690<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2691 function is using two metadata arguments.</p>
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2692
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2693 <pre class="doc_code">
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2694 call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2695 </pre>
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2696
2697<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2698 attached with <tt>add</tt> instruction using <tt>!dbg</tt> identifier.</p>
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2699
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]2700 <pre class="doc_code">
Devang Patelb1586922010-03-04 23:44:48 +0000[diff] [blame]2701 %indvar.next = add i64 %indvar, 1, !dbg !21
2702 </pre>
Chris Lattnerd0d96292010-01-15 21:50:19 +0000[diff] [blame]2703</div>
2704
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2705
2706<!-- *********************************************************************** -->
2707<div class="doc_section">
2708 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2709</div>
2710<!-- *********************************************************************** -->
2711
2712<p>LLVM has a number of "magic" global variables that contain data that affect
2713code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2714of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2715section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2716by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2717
2718<!-- ======================================================================= -->
2719<div class="doc_subsection">
2720<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2721</div>
2722
2723<div class="doc_text">
2724
2725<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2726href="#linkage_appending">appending linkage</a>. This array contains a list of
2727pointers to global variables and functions which may optionally have a pointer
2728cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2729
2730<pre>
2731 @X = global i8 4
2732 @Y = global i32 123
2733
2734 @llvm.used = appending global [2 x i8*] [
2735 i8* @X,
2736 i8* bitcast (i32* @Y to i8*)
2737 ], section "llvm.metadata"
2738</pre>
2739
2740<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2741compiler, assembler, and linker are required to treat the symbol as if there is
2742a reference to the global that it cannot see. For example, if a variable has
2743internal linkage and no references other than that from the <tt>@llvm.used</tt>
2744list, it cannot be deleted. This is commonly used to represent references from
2745inline asms and other things the compiler cannot "see", and corresponds to
2746"attribute((used))" in GNU C.</p>
2747
2748<p>On some targets, the code generator must emit a directive to the assembler or
2749object file to prevent the assembler and linker from molesting the symbol.</p>
2750
2751</div>
2752
2753<!-- ======================================================================= -->
2754<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2755<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2756</div>
2757
2758<div class="doc_text">
2759
2760<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2761<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2762touching the symbol. On targets that support it, this allows an intelligent
2763linker to optimize references to the symbol without being impeded as it would be
2764by <tt>@llvm.used</tt>.</p>
2765
2766<p>This is a rare construct that should only be used in rare circumstances, and
2767should not be exposed to source languages.</p>
2768
2769</div>
2770
2771<!-- ======================================================================= -->
2772<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2773<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2774</div>
2775
2776<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2777<pre>
2778%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2779@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2780</pre>
2781<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor functions and associated priorities. The functions referenced by this array will be called in ascending order of priority (i.e. lowest first) when the module is loaded. The order of functions with the same priority is not defined.
2782</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2783
2784</div>
2785
2786<!-- ======================================================================= -->
2787<div class="doc_subsection">
2788<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2789</div>
2790
2791<div class="doc_text">
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2792<pre>
2793%0 = type { i32, void ()* }
David Chisnalla07a3c22010-04-30 19:27:35 +0000[diff] [blame]2794@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2795</pre>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2796
David Chisnall47e8b772010-04-30 19:23:49 +0000[diff] [blame]2797<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions and associated priorities. The functions referenced by this array will be called in descending order of priority (i.e. highest first) when the module is loaded. The order of functions with the same priority is not defined.
2798</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2799
2800</div>
2801
2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803<!-- *********************************************************************** -->
2804<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2805<!-- *********************************************************************** -->
2806
2807<div class="doc_text">
2808
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2809<p>The LLVM instruction set consists of several different classifications of
2810 instructions: <a href="#terminators">terminator
2811 instructions</a>, <a href="#binaryops">binary instructions</a>,
2812 <a href="#bitwiseops">bitwise binary instructions</a>,
2813 <a href="#memoryops">memory instructions</a>, and
2814 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2815
2816</div>
2817
2818<!-- ======================================================================= -->
2819<div class="doc_subsection"> <a name="terminators">Terminator
2820Instructions</a> </div>
2821
2822<div class="doc_text">
2823
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2824<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2825 in a program ends with a "Terminator" instruction, which indicates which
2826 block should be executed after the current block is finished. These
2827 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2828 control flow, not values (the one exception being the
2829 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2830
Duncan Sands048d8062010-04-15 20:35:54 +0000[diff] [blame]2831<p>There are seven different terminator instructions: the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2832 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2833 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2834 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2835 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2836 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2837 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2838 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2839
2840</div>
2841
2842<!-- _______________________________________________________________________ -->
2843<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2844Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2849<pre>
2850 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2851 ret void <i>; Return from void function</i>
2852</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2855<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2856 a value) from a function back to the caller.</p>
2857
2858<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2859 value and then causes control flow, and one that just causes control flow to
2860 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2863<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2864 return value. The type of the return value must be a
2865 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2866
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2867<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2868 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2869 value or a return value with a type that does not match its type, or if it
2870 has a void return type and contains a '<tt>ret</tt>' instruction with a
2871 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2873<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2874<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2875 the calling function's context. If the caller is a
2876 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2877 instruction after the call. If the caller was an
2878 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2879 the beginning of the "normal" destination block. If the instruction returns
2880 a value, that value shall set the call or invoke instruction's return
2881 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2883<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2884<pre>
2885 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2887 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2890</div>
2891<!-- _______________________________________________________________________ -->
2892<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2894<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2897<pre>
2898 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2899</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2901<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2902<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2903 different basic block in the current function. There are two forms of this
2904 instruction, corresponding to a conditional branch and an unconditional
2905 branch.</p>
2906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2907<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2908<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2909 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2910 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2911 target.</p>
2912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2913<h5>Semantics:</h5>
2914<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2915 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2916 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2917 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2919<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2920<pre>
2921Test:
2922 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2923 br i1 %cond, label %IfEqual, label %IfUnequal
2924IfEqual:
2925 <a href="#i_ret">ret</a> i32 1
2926IfUnequal:
2927 <a href="#i_ret">ret</a> i32 0
2928</pre>
2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
2933<div class="doc_subsubsection">
2934 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2935</div>
2936
2937<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2938
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2939<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2940<pre>
2941 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2942</pre>
2943
2944<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2945<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2946 several different places. It is a generalization of the '<tt>br</tt>'
2947 instruction, allowing a branch to occur to one of many possible
2948 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2949
2950<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2952 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2953 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2954 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2955
2956<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2957<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2958 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2959 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2960 transferred to the corresponding destination; otherwise, control flow is
2961 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2962
2963<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2964<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2965 <tt>switch</tt> instruction, this instruction may be code generated in
2966 different ways. For example, it could be generated as a series of chained
2967 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2968
2969<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2970<pre>
2971 <i>; Emulate a conditional br instruction</i>
2972 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2973 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2974
2975 <i>; Emulate an unconditional br instruction</i>
2976 switch i32 0, label %dest [ ]
2977
2978 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2979 switch i32 %val, label %otherwise [ i32 0, label %onzero
2980 i32 1, label %onone
2981 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2982</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984</div>
2985
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2986
2987<!-- _______________________________________________________________________ -->
2988<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2989 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2990</div>
2991
2992<div class="doc_text">
2993
2994<h5>Syntax:</h5>
2995<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2996 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2997</pre>
2998
2999<h5>Overview:</h5>
3000
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3001<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3002 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]3003 "<tt>address</tt>". Address must be derived from a <a
3004 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3005
3006<h5>Arguments:</h5>
3007
3008<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3009 rest of the arguments indicate the full set of possible destinations that the
3010 address may point to. Blocks are allowed to occur multiple times in the
3011 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3012
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3013<p>This destination list is required so that dataflow analysis has an accurate
3014 understanding of the CFG.</p>
3015
3016<h5>Semantics:</h5>
3017
3018<p>Control transfers to the block specified in the address argument. All
3019 possible destination blocks must be listed in the label list, otherwise this
3020 instruction has undefined behavior. This implies that jumps to labels
3021 defined in other functions have undefined behavior as well.</p>
3022
3023<h5>Implementation:</h5>
3024
3025<p>This is typically implemented with a jump through a register.</p>
3026
3027<h5>Example:</h5>
3028<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]3029 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]3030</pre>
3031
3032</div>
3033
3034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3035<!-- _______________________________________________________________________ -->
3036<div class="doc_subsubsection">
3037 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
3038</div>
3039
3040<div class="doc_text">
3041
3042<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3044 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3045 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
3046</pre>
3047
3048<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3050 function, with the possibility of control flow transfer to either the
3051 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3052 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3053 control flow will return to the "normal" label. If the callee (or any
3054 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
3055 instruction, control is interrupted and continued at the dynamically nearest
3056 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3057
3058<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3059<p>This instruction requires several arguments:</p>
3060
3061<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3062 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3063 convention</a> the call should use. If none is specified, the call
3064 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3065
3066 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3067 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3068 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]3069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3070 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3071 function value being invoked. In most cases, this is a direct function
3072 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3073 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3074
3075 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3077
3078 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]3079 signature argument types and parameter attributes. All arguments must be
3080 of <a href="#t_firstclass">first class</a> type. If the function
3081 signature indicates the function accepts a variable number of arguments,
3082 the extra arguments can be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3083
3084 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3085 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3086
3087 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3089
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]3090 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3091 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3092 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3093</ol>
3094
3095<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3096<p>This instruction is designed to operate as a standard
3097 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3098 primary difference is that it establishes an association with a label, which
3099 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3100
3101<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3102 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3103 exception. Additionally, this is important for implementation of
3104 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3105
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3106<p>For the purposes of the SSA form, the definition of the value returned by the
3107 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3108 block to the "normal" label. If the callee unwinds then no return value is
3109 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]3110
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3111<p>Note that the code generator does not yet completely support unwind, and
3112that the invoke/unwind semantics are likely to change in future versions.</p>
3113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3114<h5>Example:</h5>
3115<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3116 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]3118 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119 unwind label %TestCleanup <i>; {i32}:retval set</i>
3120</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3121
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3122</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3123
3124<!-- _______________________________________________________________________ -->
3125
3126<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
3127Instruction</a> </div>
3128
3129<div class="doc_text">
3130
3131<h5>Syntax:</h5>
3132<pre>
3133 unwind
3134</pre>
3135
3136<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138 at the first callee in the dynamic call stack which used
3139 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
3140 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3141
3142<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3143<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3144 immediately halt. The dynamic call stack is then searched for the
3145 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
3146 Once found, execution continues at the "exceptional" destination block
3147 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
3148 instruction in the dynamic call chain, undefined behavior results.</p>
3149
Chris Lattner4a91ef42010-01-15 18:08:37 +0000[diff] [blame]3150<p>Note that the code generator does not yet completely support unwind, and
3151that the invoke/unwind semantics are likely to change in future versions.</p>
3152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153</div>
3154
3155<!-- _______________________________________________________________________ -->
3156
3157<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
3158Instruction</a> </div>
3159
3160<div class="doc_text">
3161
3162<h5>Syntax:</h5>
3163<pre>
3164 unreachable
3165</pre>
3166
3167<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3168<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3169 instruction is used to inform the optimizer that a particular portion of the
3170 code is not reachable. This can be used to indicate that the code after a
3171 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172
3173<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3176</div>
3177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178<!-- ======================================================================= -->
3179<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3181<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3182
3183<p>Binary operators are used to do most of the computation in a program. They
3184 require two operands of the same type, execute an operation on them, and
3185 produce a single value. The operands might represent multiple data, as is
3186 the case with the <a href="#t_vector">vector</a> data type. The result value
3187 has the same type as its operands.</p>
3188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3194<div class="doc_subsubsection">
3195 <a name="i_add">'<tt>add</tt>' Instruction</a>
3196</div>
3197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3198<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3200<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3201<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3202 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3203 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3204 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3205 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3206</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3208<h5>Overview:</h5>
3209<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3211<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3212<p>The two arguments to the '<tt>add</tt>' instruction must
3213 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3214 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3216<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3217<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3218
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3219<p>If the sum has unsigned overflow, the result returned is the mathematical
3220 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3221
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222<p>Because LLVM integers use a two's complement representation, this instruction
3223 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3224
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3225<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3226 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3227 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3228 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3229 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3231<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3232<pre>
3233 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3236</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3239<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3240 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
3241</div>
3242
3243<div class="doc_text">
3244
3245<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3246<pre>
3247 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3248</pre>
3249
3250<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3251<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3252
3253<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3254<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3255 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3256 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3257
3258<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3259<p>The value produced is the floating point sum of the two operands.</p>
3260
3261<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3262<pre>
3263 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3264</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3265
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3266</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3268<!-- _______________________________________________________________________ -->
3269<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3270 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
3271</div>
3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3276<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3277 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3278 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3279 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3280 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3281</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3282
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3283<h5>Overview:</h5>
3284<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3285 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3286
3287<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3288 '<tt>neg</tt>' instruction present in most other intermediate
3289 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3291<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3292<p>The two arguments to the '<tt>sub</tt>' instruction must
3293 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3294 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3296<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3297<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3298
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3299<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3300 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3301 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3302
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3303<p>Because LLVM integers use a two's complement representation, this instruction
3304 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3305
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3306<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3307 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3308 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3309 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3310 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3312<h5>Example:</h5>
3313<pre>
3314 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3315 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3316</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3318</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3320<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3321<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3322 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3323</div>
3324
3325<div class="doc_text">
3326
3327<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3328<pre>
3329 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3330</pre>
3331
3332<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3333<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3334 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3335
3336<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3337 '<tt>fneg</tt>' instruction present in most other intermediate
3338 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3339
3340<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3341<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3342 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3343 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3344
3345<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3346<p>The value produced is the floating point difference of the two operands.</p>
3347
3348<h5>Example:</h5>
3349<pre>
3350 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3351 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3352</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3353
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3354</div>
3355
3356<!-- _______________________________________________________________________ -->
3357<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3358 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3359</div>
3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3363<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3364<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3365 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3366 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3367 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3368 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3369</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3371<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3372<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3374<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3375<p>The two arguments to the '<tt>mul</tt>' instruction must
3376 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3377 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3379<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3380<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3381
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3382<p>If the result of the multiplication has unsigned overflow, the result
3383 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3384 width of the result.</p>
3385
3386<p>Because LLVM integers use a two's complement representation, and the result
3387 is the same width as the operands, this instruction returns the correct
3388 result for both signed and unsigned integers. If a full product
3389 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3390 be sign-extended or zero-extended as appropriate to the width of the full
3391 product.</p>
3392
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3393<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3394 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3395 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohmanb8ddf022010-04-22 23:14:21 +0000[diff] [blame]3396 is a <a href="#trapvalues">trap value</a> if unsigned and/or signed overflow,
3397 respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3400<pre>
3401 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3402</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3404</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3407<div class="doc_subsubsection">
3408 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3409</div>
3410
3411<div class="doc_text">
3412
3413<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3414<pre>
3415 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3416</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3417
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3418<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3419<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3420
3421<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3422<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3423 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3424 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3425
3426<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3427<p>The value produced is the floating point product of the two operands.</p>
3428
3429<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3430<pre>
3431 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3432</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3433
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3434</div>
3435
3436<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3438</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3440<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3441
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3443<pre>
3444 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3445</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3447<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3448<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3451<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3452 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3453 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3455<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3456<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3457
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3458<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3459 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3460
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3461<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3463<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3464<pre>
3465 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3466</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3468</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3470<!-- _______________________________________________________________________ -->
3471<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3472</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3474<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3475
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3476<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3477<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3478 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3479 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3480</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3483<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3486<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3487 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3488 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3491<p>The value produced is the signed integer quotient of the two operands rounded
3492 towards zero.</p>
3493
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3494<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3495 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3496
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3497<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3498 undefined behavior; this is a rare case, but can occur, for example, by doing
3499 a 32-bit division of -2147483648 by -1.</p>
3500
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3501<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]3502 <tt>sdiv</tt> is a <a href="#trapvalues">trap value</a> if the result would
Dan Gohman29297b02010-07-11 00:08:34 +0000[diff] [blame]3503 be rounded.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3505<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3506<pre>
3507 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3508</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3510</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3512<!-- _______________________________________________________________________ -->
3513<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3514Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3516<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3519<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3520 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3521</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3522
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3523<h5>Overview:</h5>
3524<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3526<h5>Arguments:</h5>
3527<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3528 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3529 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3530
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3531<h5>Semantics:</h5>
3532<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3534<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3535<pre>
3536 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3537</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3539</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3541<!-- _______________________________________________________________________ -->
3542<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3543</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3545<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3547<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3548<pre>
3549 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3550</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3552<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3553<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3554 division of its two arguments.</p>
3555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3557<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3558 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3559 values. Both arguments must have identical types.</p>
3560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561<h5>Semantics:</h5>
3562<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3563 This instruction always performs an unsigned division to get the
3564 remainder.</p>
3565
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3566<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3568
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3569<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3571<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3572<pre>
3573 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3574</pre>
3575
3576</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3578<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3579<div class="doc_subsubsection">
3580 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3581</div>
3582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3583<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3585<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3586<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3587 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3588</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3590<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3591<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3592 division of its two operands. This instruction can also take
3593 <a href="#t_vector">vector</a> versions of the values in which case the
3594 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3596<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3597<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3598 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3599 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<h5>Semantics:</h5>
3602<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3603 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3604 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3605 a value. For more information about the difference,
3606 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3607 Math Forum</a>. For a table of how this is implemented in various languages,
3608 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3609 Wikipedia: modulo operation</a>.</p>
3610
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3611<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3612 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3613
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3614<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3615 Overflow also leads to undefined behavior; this is a rare case, but can
3616 occur, for example, by taking the remainder of a 32-bit division of
3617 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3618 lets srem be implemented using instructions that return both the result of
3619 the division and the remainder.)</p>
3620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3621<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3622<pre>
3623 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624</pre>
3625
3626</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3629<div class="doc_subsubsection">
3630 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3632<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3635<pre>
3636 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3638
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3639<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3640<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3641 its two operands.</p>
3642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3643<h5>Arguments:</h5>
3644<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3645 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3646 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3649<p>This instruction returns the <i>remainder</i> of a division. The remainder
3650 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3653<pre>
3654 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3655</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3657</div>
3658
3659<!-- ======================================================================= -->
3660<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3661Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3663<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3664
3665<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3666 program. They are generally very efficient instructions and can commonly be
3667 strength reduced from other instructions. They require two operands of the
3668 same type, execute an operation on them, and produce a single value. The
3669 resulting value is the same type as its operands.</p>
3670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671</div>
3672
3673<!-- _______________________________________________________________________ -->
3674<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3675Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3677<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3679<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3680<pre>
3681 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3682</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3684<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3685<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3686 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3688<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3689<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3690 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3691 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3693<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3695 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3696 is (statically or dynamically) negative or equal to or larger than the number
3697 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3698 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3699 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3700
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3701<h5>Example:</h5>
3702<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3703 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3704 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3705 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3706 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3707 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3708</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712<!-- _______________________________________________________________________ -->
3713<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3714Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3718<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3719<pre>
3720 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3721</pre>
3722
3723<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3724<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3725 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3726
3727<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3728<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3729 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3730 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3731
3732<h5>Semantics:</h5>
3733<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3734 significant bits of the result will be filled with zero bits after the shift.
3735 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3736 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3737 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3738 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3739
3740<h5>Example:</h5>
3741<pre>
3742 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3743 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3744 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3745 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3746 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3747 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3748</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3750</div>
3751
3752<!-- _______________________________________________________________________ -->
3753<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3754Instruction</a> </div>
3755<div class="doc_text">
3756
3757<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3758<pre>
3759 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3760</pre>
3761
3762<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3763<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3764 operand shifted to the right a specified number of bits with sign
3765 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3766
3767<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3768<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3769 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3770 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771
3772<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3773<p>This instruction always performs an arithmetic shift right operation, The
3774 most significant bits of the result will be filled with the sign bit
3775 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3776 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3777 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3778 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3779
3780<h5>Example:</h5>
3781<pre>
3782 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3783 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3784 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3785 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3786 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3787 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3788</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3790</div>
3791
3792<!-- _______________________________________________________________________ -->
3793<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3794Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3795
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3796<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3798<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3799<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3800 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3801</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3803<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3804<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3805 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3807<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3808<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3809 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3810 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3812<h5>Semantics:</h5>
3813<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3815<table border="1" cellspacing="0" cellpadding="4">
3816 <tbody>
3817 <tr>
3818 <td>In0</td>
3819 <td>In1</td>
3820 <td>Out</td>
3821 </tr>
3822 <tr>
3823 <td>0</td>
3824 <td>0</td>
3825 <td>0</td>
3826 </tr>
3827 <tr>
3828 <td>0</td>
3829 <td>1</td>
3830 <td>0</td>
3831 </tr>
3832 <tr>
3833 <td>1</td>
3834 <td>0</td>
3835 <td>0</td>
3836 </tr>
3837 <tr>
3838 <td>1</td>
3839 <td>1</td>
3840 <td>1</td>
3841 </tr>
3842 </tbody>
3843</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3845<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3846<pre>
3847 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3848 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3849 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3850</pre>
3851</div>
3852<!-- _______________________________________________________________________ -->
3853<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3854
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3855<div class="doc_text">
3856
3857<h5>Syntax:</h5>
3858<pre>
3859 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3860</pre>
3861
3862<h5>Overview:</h5>
3863<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3864 two operands.</p>
3865
3866<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3867<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3868 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3869 values. Both arguments must have identical types.</p>
3870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3871<h5>Semantics:</h5>
3872<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3874<table border="1" cellspacing="0" cellpadding="4">
3875 <tbody>
3876 <tr>
3877 <td>In0</td>
3878 <td>In1</td>
3879 <td>Out</td>
3880 </tr>
3881 <tr>
3882 <td>0</td>
3883 <td>0</td>
3884 <td>0</td>
3885 </tr>
3886 <tr>
3887 <td>0</td>
3888 <td>1</td>
3889 <td>1</td>
3890 </tr>
3891 <tr>
3892 <td>1</td>
3893 <td>0</td>
3894 <td>1</td>
3895 </tr>
3896 <tr>
3897 <td>1</td>
3898 <td>1</td>
3899 <td>1</td>
3900 </tr>
3901 </tbody>
3902</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3904<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3905<pre>
3906 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3907 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3908 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3909</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3910
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3911</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3912
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913<!-- _______________________________________________________________________ -->
3914<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3915Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3917<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3919<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3920<pre>
3921 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3922</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3924<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3925<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3926 its two operands. The <tt>xor</tt> is used to implement the "one's
3927 complement" operation, which is the "~" operator in C.</p>
3928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3929<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3930<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3931 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3932 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934<h5>Semantics:</h5>
3935<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3937<table border="1" cellspacing="0" cellpadding="4">
3938 <tbody>
3939 <tr>
3940 <td>In0</td>
3941 <td>In1</td>
3942 <td>Out</td>
3943 </tr>
3944 <tr>
3945 <td>0</td>
3946 <td>0</td>
3947 <td>0</td>
3948 </tr>
3949 <tr>
3950 <td>0</td>
3951 <td>1</td>
3952 <td>1</td>
3953 </tr>
3954 <tr>
3955 <td>1</td>
3956 <td>0</td>
3957 <td>1</td>
3958 </tr>
3959 <tr>
3960 <td>1</td>
3961 <td>1</td>
3962 <td>0</td>
3963 </tr>
3964 </tbody>
3965</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3967<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3968<pre>
3969 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3970 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3971 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3972 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3973</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3975</div>
3976
3977<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3978<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979 <a name="vectorops">Vector Operations</a>
3980</div>
3981
3982<div class="doc_text">
3983
3984<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3985 target-independent manner. These instructions cover the element-access and
3986 vector-specific operations needed to process vectors effectively. While LLVM
3987 does directly support these vector operations, many sophisticated algorithms
3988 will want to use target-specific intrinsics to take full advantage of a
3989 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990
3991</div>
3992
3993<!-- _______________________________________________________________________ -->
3994<div class="doc_subsubsection">
3995 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3996</div>
3997
3998<div class="doc_text">
3999
4000<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4001<pre>
4002 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
4003</pre>
4004
4005<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4006<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4007 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4008
4009
4010<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4012 of <a href="#t_vector">vector</a> type. The second operand is an index
4013 indicating the position from which to extract the element. The index may be
4014 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015
4016<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4017<p>The result is a scalar of the same type as the element type of
4018 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4019 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4020 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4021
4022<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4023<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4024 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4025</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4027</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4028
4029<!-- _______________________________________________________________________ -->
4030<div class="doc_subsubsection">
4031 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
4032</div>
4033
4034<div class="doc_text">
4035
4036<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4037<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]4038 &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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039</pre>
4040
4041<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4042<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4043 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044
4045<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4046<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4047 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4048 whose type must equal the element type of the first operand. The third
4049 operand is an index indicating the position at which to insert the value.
4050 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051
4052<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4053<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4054 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4055 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4056 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057
4058<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4059<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4060 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4063</div>
4064
4065<!-- _______________________________________________________________________ -->
4066<div class="doc_subsubsection">
4067 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
4068</div>
4069
4070<div class="doc_text">
4071
4072<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4073<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4074 &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;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4075</pre>
4076
4077<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4078<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4079 from two input vectors, returning a vector with the same element type as the
4080 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4081
4082<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4083<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4084 with types that match each other. The third argument is a shuffle mask whose
4085 element type is always 'i32'. The result of the instruction is a vector
4086 whose length is the same as the shuffle mask and whose element type is the
4087 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4089<p>The shuffle mask operand is required to be a constant vector with either
4090 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4091
4092<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4093<p>The elements of the two input vectors are numbered from left to right across
4094 both of the vectors. The shuffle mask operand specifies, for each element of
4095 the result vector, which element of the two input vectors the result element
4096 gets. The element selector may be undef (meaning "don't care") and the
4097 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4098
4099<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4100<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4101 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4102 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4103 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4104 &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.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4105 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4106 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4107 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]4108 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4109</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4110
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4111</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4112
4113<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4114<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4115 <a name="aggregateops">Aggregate Operations</a>
4116</div>
4117
4118<div class="doc_text">
4119
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4120<p>LLVM supports several instructions for working with
4121 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4122
4123</div>
4124
4125<!-- _______________________________________________________________________ -->
4126<div class="doc_subsubsection">
4127 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
4128</div>
4129
4130<div class="doc_text">
4131
4132<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4133<pre>
4134 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4135</pre>
4136
4137<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4138<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4139 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4140
4141<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4142<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4143 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4144 <a href="#t_array">array</a> type. The operands are constant indices to
4145 specify which value to extract in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4146 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4147
4148<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4149<p>The result is the value at the position in the aggregate specified by the
4150 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4151
4152<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4153<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]4154 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4155</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4156
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4157</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4158
4159<!-- _______________________________________________________________________ -->
4160<div class="doc_subsubsection">
4161 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
4162</div>
4163
4164<div class="doc_text">
4165
4166<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4167<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4168 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4169</pre>
4170
4171<h5>Overview:</h5>
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4172<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4173 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4174
4175<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4176<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4177 of <a href="#t_struct">struct</a>, <a href="#t_union">union</a> or
4178 <a href="#t_array">array</a> type. The second operand is a first-class
4179 value to insert. The following operands are constant indices indicating
4180 the position at which to insert the value in a similar manner as indices in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4181 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
4182 value to insert must have the same type as the value identified by the
4183 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4184
4185<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4186<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4187 that of <tt>val</tt> except that the value at the position specified by the
4188 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4189
4190<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4191<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]4192 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4193 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4194</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4195
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]4196</div>
4197
4198
4199<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4200<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4201 <a name="memoryops">Memory Access and Addressing Operations</a>
4202</div>
4203
4204<div class="doc_text">
4205
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4206<p>A key design point of an SSA-based representation is how it represents
4207 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]4208 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4209 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210
4211</div>
4212
4213<!-- _______________________________________________________________________ -->
4214<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4215 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
4216</div>
4217
4218<div class="doc_text">
4219
4220<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221<pre>
Dan Gohman3eb67d52010-05-28 01:14:11 +0000[diff] [blame]4222 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4223</pre>
4224
4225<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4227 currently executing function, to be automatically released when this function
4228 returns to its caller. The object is always allocated in the generic address
4229 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4230
4231<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4232<p>The '<tt>alloca</tt>' instruction
4233 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4234 runtime stack, returning a pointer of the appropriate type to the program.
4235 If "NumElements" is specified, it is the number of elements allocated,
4236 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4237 specified, the value result of the allocation is guaranteed to be aligned to
4238 at least that boundary. If not specified, or if zero, the target can choose
4239 to align the allocation on any convenient boundary compatible with the
4240 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241
4242<p>'<tt>type</tt>' may be any sized type.</p>
4243
4244<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]4245<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4246 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4247 memory is automatically released when the function returns. The
4248 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4249 variables that must have an address available. When the function returns
4250 (either with the <tt><a href="#i_ret">ret</a></tt>
4251 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
4252 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253
4254<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]4256 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4257 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4258 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4259 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4262</div>
4263
4264<!-- _______________________________________________________________________ -->
4265<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
4266Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4270<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4271<pre>
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4272 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4273 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;]
4274 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4275</pre>
4276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4277<h5>Overview:</h5>
4278<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4280<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4281<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4282 from which to load. The pointer must point to
4283 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4284 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4285 number or order of execution of this <tt>load</tt> with other <a
4286 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4287
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4288<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4289 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4290 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4291 alignment for the target. It is the responsibility of the code emitter to
4292 ensure that the alignment information is correct. Overestimating the
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4293 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4294 produce less efficient code. An alignment of 1 is always safe.</p>
4295
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4296<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4297 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4298 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendling4197e452010-02-25 21:23:24 +0000[diff] [blame]4299 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4300 and code generator that this load is not expected to be reused in the cache.
4301 The code generator may select special instructions to save cache bandwidth,
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4302 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4304<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4305<p>The location of memory pointed to is loaded. If the value being loaded is of
4306 scalar type then the number of bytes read does not exceed the minimum number
4307 of bytes needed to hold all bits of the type. For example, loading an
4308 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4309 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4310 is undefined if the value was not originally written using a store of the
4311 same type.</p>
4312
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4313<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4314<pre>
4315 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4316 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4317 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4318</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4320</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322<!-- _______________________________________________________________________ -->
4323<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4324Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4325
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4326<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4328<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4329<pre>
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4330 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4331 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4332</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4334<h5>Overview:</h5>
4335<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4336
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4337<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4338<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4339 and an address at which to store it. The type of the
4340 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4341 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]4342 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4343 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4344 order of execution of this <tt>store</tt> with other <a
4345 href="#volatile">volatile operations</a>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4346
4347<p>The optional constant "align" argument specifies the alignment of the
4348 operation (that is, the alignment of the memory address). A value of 0 or an
4349 omitted "align" argument means that the operation has the preferential
4350 alignment for the target. It is the responsibility of the code emitter to
4351 ensure that the alignment information is correct. Overestimating the
4352 alignment results in an undefined behavior. Underestimating the alignment may
4353 produce less efficient code. An alignment of 1 is always safe.</p>
4354
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4355<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4356 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4357 value 1. The existence of the !nontemporal metatadata on the
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4358 instruction tells the optimizer and code generator that this load is
4359 not expected to be reused in the cache. The code generator may
4360 select special instructions to save cache bandwidth, such as the
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]4361 MOVNT instruction on x86.</p>
David Greene02dfe202010-02-16 20:50:18 +0000[diff] [blame]4362
4363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4364<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4365<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4366 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4367 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4368 does not exceed the minimum number of bytes needed to hold all bits of the
4369 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4370 writing a value of a type like <tt>i20</tt> with a size that is not an
4371 integral number of bytes, it is unspecified what happens to the extra bits
4372 that do not belong to the type, but they will typically be overwritten.</p>
4373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4374<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4375<pre>
4376 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4377 store i32 3, i32* %ptr <i>; yields {void}</i>
4378 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4379</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4381</div>
4382
4383<!-- _______________________________________________________________________ -->
4384<div class="doc_subsubsection">
4385 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4386</div>
4387
4388<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390<h5>Syntax:</h5>
4391<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4392 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4393 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394</pre>
4395
4396<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4397<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4398 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
4399 It performs address calculation only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4400
4401<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4402<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4403 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4404 elements of the aggregate object are indexed. The interpretation of each
4405 index is dependent on the type being indexed into. The first index always
4406 indexes the pointer value given as the first argument, the second index
4407 indexes a value of the type pointed to (not necessarily the value directly
4408 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4409 indexed into must be a pointer value, subsequent types can be arrays,
4410 vectors, structs and unions. Note that subsequent types being indexed into
4411 can never be pointers, since that would require loading the pointer before
4412 continuing calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4413
4414<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnerd5d51722010-02-12 20:49:41 +0000[diff] [blame]4415 When indexing into a (optionally packed) structure or union, only <tt>i32</tt>
4416 integer <b>constants</b> are allowed. When indexing into an array, pointer
4417 or vector, integers of any width are allowed, and they are not required to be
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4418 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4419
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4420<p>For example, let's consider a C code fragment and how it gets compiled to
4421 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4422
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4423<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4424struct RT {
4425 char A;
4426 int B[10][20];
4427 char C;
4428};
4429struct ST {
4430 int X;
4431 double Y;
4432 struct RT Z;
4433};
4434
4435int *foo(struct ST *s) {
4436 return &amp;s[1].Z.B[5][13];
4437}
4438</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4439
4440<p>The LLVM code generated by the GCC frontend is:</p>
4441
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]4442<pre class="doc_code">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4443%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4444%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4446define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447entry:
4448 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4449 ret i32* %reg
4450}
4451</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4452
4453<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4455 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4456 }</tt>' type, a structure. The second index indexes into the third element
4457 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4458 i8 }</tt>' type, another structure. The third index indexes into the second
4459 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4460 array. The two dimensions of the array are subscripted into, yielding an
4461 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4462 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4463
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4464<p>Note that it is perfectly legal to index partially through a structure,
4465 returning a pointer to an inner element. Because of this, the LLVM code for
4466 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4467
4468<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4469 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4470 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4471 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4472 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4473 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4474 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4475 ret i32* %t5
4476 }
4477</pre>
4478
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4479<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohmanf7263862010-04-23 15:23:32 +0000[diff] [blame]4480 <tt>getelementptr</tt> is a <a href="#trapvalues">trap value</a> if the
4481 base pointer is not an <i>in bounds</i> address of an allocated object,
4482 or if any of the addresses that would be formed by successive addition of
4483 the offsets implied by the indices to the base address with infinitely
4484 precise arithmetic are not an <i>in bounds</i> address of that allocated
4485 object. The <i>in bounds</i> addresses for an allocated object are all
4486 the addresses that point into the object, plus the address one byte past
4487 the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4488
4489<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4490 the base address with silently-wrapping two's complement arithmetic, and
4491 the result value of the <tt>getelementptr</tt> may be outside the object
4492 pointed to by the base pointer. The result value may not necessarily be
4493 used to access memory though, even if it happens to point into allocated
4494 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4495 section for more information.</p>
4496
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4497<p>The getelementptr instruction is often confusing. For some more insight into
4498 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499
4500<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501<pre>
4502 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4503 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4504 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4505 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4506 <i>; yields i8*:eptr</i>
4507 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4508 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4509 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4512</div>
4513
4514<!-- ======================================================================= -->
4515<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4516</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4518<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4519
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4520<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4521 which all take a single operand and a type. They perform various bit
4522 conversions on the operand.</p>
4523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection">
4528 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4529</div>
4530<div class="doc_text">
4531
4532<h5>Syntax:</h5>
4533<pre>
4534 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4535</pre>
4536
4537<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4539 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540
4541<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4543 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4544 size and type of the result, which must be
4545 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4546 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4547 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4548
4549<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4550<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4551 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4552 source size must be larger than the destination size, <tt>trunc</tt> cannot
4553 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4554
4555<h5>Example:</h5>
4556<pre>
4557 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4558 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4559 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4560</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4562</div>
4563
4564<!-- _______________________________________________________________________ -->
4565<div class="doc_subsubsection">
4566 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4567</div>
4568<div class="doc_text">
4569
4570<h5>Syntax:</h5>
4571<pre>
4572 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4573</pre>
4574
4575<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4576<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4577 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4578
4579
4580<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4581<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4582 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4583 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4584 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4585 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4586
4587<h5>Semantics:</h5>
4588<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4589 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590
4591<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4592
4593<h5>Example:</h5>
4594<pre>
4595 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4596 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4597</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4599</div>
4600
4601<!-- _______________________________________________________________________ -->
4602<div class="doc_subsubsection">
4603 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4604</div>
4605<div class="doc_text">
4606
4607<h5>Syntax:</h5>
4608<pre>
4609 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4610</pre>
4611
4612<h5>Overview:</h5>
4613<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4614
4615<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4616<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4617 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4618 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4619 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4620 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4621
4622<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4623<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4624 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4625 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4626
4627<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4628
4629<h5>Example:</h5>
4630<pre>
4631 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4632 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4633</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4635</div>
4636
4637<!-- _______________________________________________________________________ -->
4638<div class="doc_subsubsection">
4639 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4640</div>
4641
4642<div class="doc_text">
4643
4644<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4645<pre>
4646 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4647</pre>
4648
4649<h5>Overview:</h5>
4650<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4651 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4652
4653<h5>Arguments:</h5>
4654<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4656 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4657 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4658 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4659
4660<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4661<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4662 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4663 <a href="#t_floating">floating point</a> type. If the value cannot fit
4664 within the destination type, <tt>ty2</tt>, then the results are
4665 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666
4667<h5>Example:</h5>
4668<pre>
4669 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4670 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4671</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673</div>
4674
4675<!-- _______________________________________________________________________ -->
4676<div class="doc_subsubsection">
4677 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4678</div>
4679<div class="doc_text">
4680
4681<h5>Syntax:</h5>
4682<pre>
4683 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4684</pre>
4685
4686<h5>Overview:</h5>
4687<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4688 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4689
4690<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4691<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4692 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4693 a <a href="#t_floating">floating point</a> type to cast it to. The source
4694 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4695
4696<h5>Semantics:</h5>
4697<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4698 <a href="#t_floating">floating point</a> type to a larger
4699 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4700 used to make a <i>no-op cast</i> because it always changes bits. Use
4701 <tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4702
4703<h5>Example:</h5>
4704<pre>
4705 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4706 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4707</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4708
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4709</div>
4710
4711<!-- _______________________________________________________________________ -->
4712<div class="doc_subsubsection">
4713 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4714</div>
4715<div class="doc_text">
4716
4717<h5>Syntax:</h5>
4718<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4719 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720</pre>
4721
4722<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4723<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4725
4726<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4728 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4729 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4730 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4731 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732
4733<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4734<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4735 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4736 towards zero) unsigned integer value. If the value cannot fit
4737 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4739<h5>Example:</h5>
4740<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4741 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4742 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4743 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4744</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4745
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4746</div>
4747
4748<!-- _______________________________________________________________________ -->
4749<div class="doc_subsubsection">
4750 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4751</div>
4752<div class="doc_text">
4753
4754<h5>Syntax:</h5>
4755<pre>
4756 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4757</pre>
4758
4759<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4760<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4761 <a href="#t_floating">floating point</a> <tt>value</tt> to
4762 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4764<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4765<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4766 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4767 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4768 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4769 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4770
4771<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4772<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4773 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4774 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4775 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4777<h5>Example:</h5>
4778<pre>
4779 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4780 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4781 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4782</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4784</div>
4785
4786<!-- _______________________________________________________________________ -->
4787<div class="doc_subsubsection">
4788 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4789</div>
4790<div class="doc_text">
4791
4792<h5>Syntax:</h5>
4793<pre>
4794 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4795</pre>
4796
4797<h5>Overview:</h5>
4798<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4799 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4801<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4802<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4803 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4804 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4805 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4806 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4807
4808<h5>Semantics:</h5>
4809<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4810 integer quantity and converts it to the corresponding floating point
4811 value. If the value cannot fit in the floating point value, the results are
4812 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4814<h5>Example:</h5>
4815<pre>
4816 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4817 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4818</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4820</div>
4821
4822<!-- _______________________________________________________________________ -->
4823<div class="doc_subsubsection">
4824 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4825</div>
4826<div class="doc_text">
4827
4828<h5>Syntax:</h5>
4829<pre>
4830 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4831</pre>
4832
4833<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4834<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4835 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4836
4837<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4838<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4839 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4840 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4841 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4842 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4843
4844<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4845<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4846 quantity and converts it to the corresponding floating point value. If the
4847 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848
4849<h5>Example:</h5>
4850<pre>
4851 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4852 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4853</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4855</div>
4856
4857<!-- _______________________________________________________________________ -->
4858<div class="doc_subsubsection">
4859 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4860</div>
4861<div class="doc_text">
4862
4863<h5>Syntax:</h5>
4864<pre>
4865 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4866</pre>
4867
4868<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4869<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4870 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4871
4872<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4873<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4874 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4875 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4876
4877<h5>Semantics:</h5>
4878<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4879 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4880 truncating or zero extending that value to the size of the integer type. If
4881 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4882 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4883 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4884 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4885
4886<h5>Example:</h5>
4887<pre>
4888 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4889 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4890</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4892</div>
4893
4894<!-- _______________________________________________________________________ -->
4895<div class="doc_subsubsection">
4896 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4897</div>
4898<div class="doc_text">
4899
4900<h5>Syntax:</h5>
4901<pre>
4902 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4903</pre>
4904
4905<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4906<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4907 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4908
4909<h5>Arguments:</h5>
4910<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4911 value to cast, and a type to cast it to, which must be a
4912 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4913
4914<h5>Semantics:</h5>
4915<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4916 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4917 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4918 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4919 than the size of a pointer then a zero extension is done. If they are the
4920 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921
4922<h5>Example:</h5>
4923<pre>
4924 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4925 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4926 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4927</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4929</div>
4930
4931<!-- _______________________________________________________________________ -->
4932<div class="doc_subsubsection">
4933 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4934</div>
4935<div class="doc_text">
4936
4937<h5>Syntax:</h5>
4938<pre>
4939 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4940</pre>
4941
4942<h5>Overview:</h5>
4943<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4944 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4945
4946<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4947<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4948 non-aggregate first class value, and a type to cast it to, which must also be
4949 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4950 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4951 identical. If the source type is a pointer, the destination type must also be
4952 a pointer. This instruction supports bitwise conversion of vectors to
4953 integers and to vectors of other types (as long as they have the same
4954 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4955
4956<h5>Semantics:</h5>
4957<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4958 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4959 this conversion. The conversion is done as if the <tt>value</tt> had been
4960 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4961 be converted to other pointer types with this instruction. To convert
4962 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4963 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4964
4965<h5>Example:</h5>
4966<pre>
4967 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4968 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4969 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4970</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4972</div>
4973
4974<!-- ======================================================================= -->
4975<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4977<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4978
4979<p>The instructions in this category are the "miscellaneous" instructions, which
4980 defy better classification.</p>
4981
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4982</div>
4983
4984<!-- _______________________________________________________________________ -->
4985<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4986</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4988<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4990<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4991<pre>
4992 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4993</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4994
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4995<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4996<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4997 boolean values based on comparison of its two integer, integer vector, or
4998 pointer operands.</p>
4999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5000<h5>Arguments:</h5>
5001<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5002 the condition code indicating the kind of comparison to perform. It is not a
5003 value, just a keyword. The possible condition code are:</p>
5004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5005<ol>
5006 <li><tt>eq</tt>: equal</li>
5007 <li><tt>ne</tt>: not equal </li>
5008 <li><tt>ugt</tt>: unsigned greater than</li>
5009 <li><tt>uge</tt>: unsigned greater or equal</li>
5010 <li><tt>ult</tt>: unsigned less than</li>
5011 <li><tt>ule</tt>: unsigned less or equal</li>
5012 <li><tt>sgt</tt>: signed greater than</li>
5013 <li><tt>sge</tt>: signed greater or equal</li>
5014 <li><tt>slt</tt>: signed less than</li>
5015 <li><tt>sle</tt>: signed less or equal</li>
5016</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5017
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5018<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5019 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5020 typed. They must also be identical types.</p>
5021
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5023<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5024 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5025 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5026 result, as follows:</p>
5027
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5028<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5029 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5030 <tt>false</tt> otherwise. No sign interpretation is necessary or
5031 performed.</li>
5032
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5033 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5034 <tt>false</tt> otherwise. No sign interpretation is necessary or
5035 performed.</li>
5036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5037 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5038 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5040 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5041 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5042 to <tt>op2</tt>.</li>
5043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5044 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5045 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5046
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5047 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5048 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5050 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5051 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5053 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5054 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5055 to <tt>op2</tt>.</li>
5056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5057 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5058 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5059
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5060 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5061 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5062</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5064<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5065 values are compared as if they were integers.</p>
5066
5067<p>If the operands are integer vectors, then they are compared element by
5068 element. The result is an <tt>i1</tt> vector with the same number of elements
5069 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5070
5071<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5072<pre>
5073 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5075 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5076 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5077 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5078 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
5079</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5080
5081<p>Note that the code generator does not yet support vector types with
5082 the <tt>icmp</tt> instruction.</p>
5083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5084</div>
5085
5086<!-- _______________________________________________________________________ -->
5087<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5088</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5090<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5093<pre>
5094 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5095</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5097<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5098<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5099 values based on comparison of its operands.</p>
5100
5101<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5102(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5103
5104<p>If the operands are floating point vectors, then the result type is a vector
5105 of boolean with the same number of elements as the operands being
5106 compared.</p>
5107
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5108<h5>Arguments:</h5>
5109<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5110 the condition code indicating the kind of comparison to perform. It is not a
5111 value, just a keyword. The possible condition code are:</p>
5112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5113<ol>
5114 <li><tt>false</tt>: no comparison, always returns false</li>
5115 <li><tt>oeq</tt>: ordered and equal</li>
5116 <li><tt>ogt</tt>: ordered and greater than </li>
5117 <li><tt>oge</tt>: ordered and greater than or equal</li>
5118 <li><tt>olt</tt>: ordered and less than </li>
5119 <li><tt>ole</tt>: ordered and less than or equal</li>
5120 <li><tt>one</tt>: ordered and not equal</li>
5121 <li><tt>ord</tt>: ordered (no nans)</li>
5122 <li><tt>ueq</tt>: unordered or equal</li>
5123 <li><tt>ugt</tt>: unordered or greater than </li>
5124 <li><tt>uge</tt>: unordered or greater than or equal</li>
5125 <li><tt>ult</tt>: unordered or less than </li>
5126 <li><tt>ule</tt>: unordered or less than or equal</li>
5127 <li><tt>une</tt>: unordered or not equal</li>
5128 <li><tt>uno</tt>: unordered (either nans)</li>
5129 <li><tt>true</tt>: no comparison, always returns true</li>
5130</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5132<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5133 <i>unordered</i> means that either operand may be a QNAN.</p>
5134
5135<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5136 a <a href="#t_floating">floating point</a> type or
5137 a <a href="#t_vector">vector</a> of floating point type. They must have
5138 identical types.</p>
5139
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5140<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]5141<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5142 according to the condition code given as <tt>cond</tt>. If the operands are
5143 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]5144 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5145 follows:</p>
5146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5147<ol>
5148 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5149
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5150 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5151 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5153 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5154 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5155
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5156 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5157 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5158
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5159 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5160 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5161
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5162 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5163 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5164
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5165 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5166 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5168 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5169
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5170 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5171 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5172
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5173 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5174 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5175
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5176 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5177 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5178
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5179 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5180 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5181
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5182 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5183 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5184
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5185 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5186 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5188 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
5191</ol>
5192
5193<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5194<pre>
5195 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5196 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
5197 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
5198 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5199</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5200
5201<p>Note that the code generator does not yet support vector types with
5202 the <tt>fcmp</tt> instruction.</p>
5203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5204</div>
5205
5206<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]5207<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5208 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
5209</div>
5210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5211<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5213<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5214<pre>
5215 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
5216</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5218<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5219<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
5220 SSA graph representing the function.</p>
5221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5222<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5223<p>The type of the incoming values is specified with the first type field. After
5224 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
5225 one pair for each predecessor basic block of the current block. Only values
5226 of <a href="#t_firstclass">first class</a> type may be used as the value
5227 arguments to the PHI node. Only labels may be used as the label
5228 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5229
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5230<p>There must be no non-phi instructions between the start of a basic block and
5231 the PHI instructions: i.e. PHI instructions must be first in a basic
5232 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5233
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5234<p>For the purposes of the SSA form, the use of each incoming value is deemed to
5235 occur on the edge from the corresponding predecessor block to the current
5236 block (but after any definition of an '<tt>invoke</tt>' instruction's return
5237 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]5238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5239<h5>Semantics:</h5>
5240<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5241 specified by the pair corresponding to the predecessor basic block that
5242 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5244<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]5245<pre>
5246Loop: ; Infinite loop that counts from 0 on up...
5247 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
5248 %nextindvar = add i32 %indvar, 1
5249 br label %Loop
5250</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5252</div>
5253
5254<!-- _______________________________________________________________________ -->
5255<div class="doc_subsubsection">
5256 <a name="i_select">'<tt>select</tt>' Instruction</a>
5257</div>
5258
5259<div class="doc_text">
5260
5261<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5262<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]5263 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
5264
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5265 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5266</pre>
5267
5268<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5269<p>The '<tt>select</tt>' instruction is used to choose one value based on a
5270 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271
5272
5273<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5274<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
5275 values indicating the condition, and two values of the
5276 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
5277 vectors and the condition is a scalar, then entire vectors are selected, not
5278 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279
5280<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5281<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
5282 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5283
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5284<p>If the condition is a vector of i1, then the value arguments must be vectors
5285 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5286
5287<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5288<pre>
5289 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5290</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5291
5292<p>Note that the code generator does not yet support conditions
5293 with vector type.</p>
5294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5295</div>
5296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5297<!-- _______________________________________________________________________ -->
5298<div class="doc_subsubsection">
5299 <a name="i_call">'<tt>call</tt>' Instruction</a>
5300</div>
5301
5302<div class="doc_text">
5303
5304<h5>Syntax:</h5>
5305<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5306 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5307</pre>
5308
5309<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5311
5312<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5313<p>This instruction requires several arguments:</p>
5314
5315<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5316 <li>The optional "tail" marker indicates that the callee function does not
5317 access any allocas or varargs in the caller. Note that calls may be
5318 marked "tail" even if they do not occur before
5319 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5320 present, the function call is eligible for tail call optimization,
5321 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Chengcc7495c2010-03-08 21:05:02 +0000[diff] [blame]5322 optimized into a jump</a>. The code generator may optimize calls marked
5323 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
5324 sibling call optimization</a> when the caller and callee have
5325 matching signatures, or 2) forced tail call optimization when the
5326 following extra requirements are met:
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5327 <ul>
5328 <li>Caller and callee both have the calling
5329 convention <tt>fastcc</tt>.</li>
5330 <li>The call is in tail position (ret immediately follows call and ret
5331 uses value of call or is void).</li>
5332 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman1be84f02010-03-02 01:08:11 +0000[diff] [blame]5333 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5334 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5335 constraints are met.</a></li>
5336 </ul>
5337 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5338
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5339 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5340 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5341 defaults to using C calling conventions. The calling convention of the
5342 call must match the calling convention of the target function, or else the
5343 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5344
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5345 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5346 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5347 '<tt>inreg</tt>' attributes are valid here.</li>
5348
5349 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5350 type of the return value. Functions that return no value are marked
5351 <tt><a href="#t_void">void</a></tt>.</li>
5352
5353 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5354 being invoked. The argument types must match the types implied by this
5355 signature. This type can be omitted if the function is not varargs and if
5356 the function type does not return a pointer to a function.</li>
5357
5358 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5359 be invoked. In most cases, this is a direct function invocation, but
5360 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5361 to function value.</li>
5362
5363 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner553fb1e2010-03-02 06:36:51 +0000[diff] [blame]5364 signature argument types and parameter attributes. All arguments must be
5365 of <a href="#t_firstclass">first class</a> type. If the function
5366 signature indicates the function accepts a variable number of arguments,
5367 the extra arguments can be specified.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5368
5369 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5370 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5371 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5372</ol>
5373
5374<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5375<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5376 a specified function, with its incoming arguments bound to the specified
5377 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5378 function, control flow continues with the instruction after the function
5379 call, and the return value of the function is bound to the result
5380 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5381
5382<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5383<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5384 %retval = call i32 @test(i32 %argc)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5385 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5386 %X = tail call i32 @foo() <i>; yields i32</i>
5387 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5388 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5389
5390 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5391 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5392 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5393 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5394 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5395 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5396</pre>
5397
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5398<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5399standard C99 library as being the C99 library functions, and may perform
5400optimizations or generate code for them under that assumption. This is
5401something we'd like to change in the future to provide better support for
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5402freestanding environments and non-C-based languages.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5404</div>
5405
5406<!-- _______________________________________________________________________ -->
5407<div class="doc_subsubsection">
5408 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5409</div>
5410
5411<div class="doc_text">
5412
5413<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5414<pre>
5415 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5416</pre>
5417
5418<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5419<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5420 the "variable argument" area of a function call. It is used to implement the
5421 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5422
5423<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5424<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5425 argument. It returns a value of the specified argument type and increments
5426 the <tt>va_list</tt> to point to the next argument. The actual type
5427 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5428
5429<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5430<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5431 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5432 to the next argument. For more information, see the variable argument
5433 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434
5435<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5436 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5437 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5438
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5439<p><tt>va_arg</tt> is an LLVM instruction instead of
5440 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5441 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5442
5443<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5444<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5445
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5446<p>Note that the code generator does not yet fully support va_arg on many
5447 targets. Also, it does not currently support va_arg with aggregate types on
5448 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450</div>
5451
5452<!-- *********************************************************************** -->
5453<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5454<!-- *********************************************************************** -->
5455
5456<div class="doc_text">
5457
5458<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5459 well known names and semantics and are required to follow certain
5460 restrictions. Overall, these intrinsics represent an extension mechanism for
5461 the LLVM language that does not require changing all of the transformations
5462 in LLVM when adding to the language (or the bitcode reader/writer, the
5463 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5464
5465<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5466 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5467 begin with this prefix. Intrinsic functions must always be external
5468 functions: you cannot define the body of intrinsic functions. Intrinsic
5469 functions may only be used in call or invoke instructions: it is illegal to
5470 take the address of an intrinsic function. Additionally, because intrinsic
5471 functions are part of the LLVM language, it is required if any are added that
5472 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5474<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5475 family of functions that perform the same operation but on different data
5476 types. Because LLVM can represent over 8 million different integer types,
5477 overloading is used commonly to allow an intrinsic function to operate on any
5478 integer type. One or more of the argument types or the result type can be
5479 overloaded to accept any integer type. Argument types may also be defined as
5480 exactly matching a previous argument's type or the result type. This allows
5481 an intrinsic function which accepts multiple arguments, but needs all of them
5482 to be of the same type, to only be overloaded with respect to a single
5483 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5485<p>Overloaded intrinsics will have the names of its overloaded argument types
5486 encoded into its function name, each preceded by a period. Only those types
5487 which are overloaded result in a name suffix. Arguments whose type is matched
5488 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5489 can take an integer of any width and returns an integer of exactly the same
5490 integer width. This leads to a family of functions such as
5491 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5492 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5493 suffix is required. Because the argument's type is matched against the return
5494 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5495
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5496<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5497 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5498
5499</div>
5500
5501<!-- ======================================================================= -->
5502<div class="doc_subsection">
5503 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5504</div>
5505
5506<div class="doc_text">
5507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5508<p>Variable argument support is defined in LLVM with
5509 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5510 intrinsic functions. These functions are related to the similarly named
5511 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5512
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5513<p>All of these functions operate on arguments that use a target-specific value
5514 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5515 not define what this type is, so all transformations should be prepared to
5516 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5517
5518<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5519 instruction and the variable argument handling intrinsic functions are
5520 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]5522<pre class="doc_code">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5523define i32 @test(i32 %X, ...) {
5524 ; Initialize variable argument processing
5525 %ap = alloca i8*
5526 %ap2 = bitcast i8** %ap to i8*
5527 call void @llvm.va_start(i8* %ap2)
5528
5529 ; Read a single integer argument
5530 %tmp = va_arg i8** %ap, i32
5531
5532 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5533 %aq = alloca i8*
5534 %aq2 = bitcast i8** %aq to i8*
5535 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5536 call void @llvm.va_end(i8* %aq2)
5537
5538 ; Stop processing of arguments.
5539 call void @llvm.va_end(i8* %ap2)
5540 ret i32 %tmp
5541}
5542
5543declare void @llvm.va_start(i8*)
5544declare void @llvm.va_copy(i8*, i8*)
5545declare void @llvm.va_end(i8*)
5546</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5547
5548</div>
5549
5550<!-- _______________________________________________________________________ -->
5551<div class="doc_subsubsection">
5552 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5553</div>
5554
5555
5556<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5558<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5559<pre>
5560 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5561</pre>
5562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5563<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5564<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5565 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566
5567<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5568<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5569
5570<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5571<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5572 macro available in C. In a target-dependent way, it initializes
5573 the <tt>va_list</tt> element to which the argument points, so that the next
5574 call to <tt>va_arg</tt> will produce the first variable argument passed to
5575 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5576 need to know the last argument of the function as the compiler can figure
5577 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5578
5579</div>
5580
5581<!-- _______________________________________________________________________ -->
5582<div class="doc_subsubsection">
5583 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5584</div>
5585
5586<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5587
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5588<h5>Syntax:</h5>
5589<pre>
5590 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5591</pre>
5592
5593<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5595 which has been initialized previously
5596 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5597 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598
5599<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5600<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5601
5602<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5603<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5604 macro available in C. In a target-dependent way, it destroys
5605 the <tt>va_list</tt> element to which the argument points. Calls
5606 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5607 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5608 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5609
5610</div>
5611
5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
5614 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5620<pre>
5621 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5622</pre>
5623
5624<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5625<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5626 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5627
5628<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5629<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5630 The second argument is a pointer to a <tt>va_list</tt> element to copy
5631 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5632
5633<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5635 macro available in C. In a target-dependent way, it copies the
5636 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5637 element. This intrinsic is necessary because
5638 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5639 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5640
5641</div>
5642
5643<!-- ======================================================================= -->
5644<div class="doc_subsection">
5645 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5646</div>
5647
5648<div class="doc_text">
5649
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5650<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5651Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5652intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5653roots on the stack</a>, as well as garbage collector implementations that
5654require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5655barriers. Front-ends for type-safe garbage collected languages should generate
5656these intrinsics to make use of the LLVM garbage collectors. For more details,
5657see <a href="GarbageCollection.html">Accurate Garbage Collection with
5658LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5659
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5660<p>The garbage collection intrinsics only operate on objects in the generic
5661 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663</div>
5664
5665<!-- _______________________________________________________________________ -->
5666<div class="doc_subsubsection">
5667 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5668</div>
5669
5670<div class="doc_text">
5671
5672<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5673<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5674 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5675</pre>
5676
5677<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5678<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5679 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5680
5681<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5682<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5683 root pointer. The second pointer (which must be either a constant or a
5684 global value address) contains the meta-data to be associated with the
5685 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5686
5687<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5688<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5689 location. At compile-time, the code generator generates information to allow
5690 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5691 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5692 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693
5694</div>
5695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5696<!-- _______________________________________________________________________ -->
5697<div class="doc_subsubsection">
5698 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5699</div>
5700
5701<div class="doc_text">
5702
5703<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5704<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5705 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5706</pre>
5707
5708<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5710 locations, allowing garbage collector implementations that require read
5711 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5712
5713<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5714<p>The second argument is the address to read from, which should be an address
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5715 allocated from the garbage collector. The first object is a pointer to the
5716 start of the referenced object, if needed by the language runtime (otherwise
5717 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5718
5719<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5720<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5721 instruction, but may be replaced with substantially more complex code by the
5722 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5723 may only be used in a function which <a href="#gc">specifies a GC
5724 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725
5726</div>
5727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5728<!-- _______________________________________________________________________ -->
5729<div class="doc_subsubsection">
5730 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5731</div>
5732
5733<div class="doc_text">
5734
5735<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5736<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5737 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738</pre>
5739
5740<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5742 locations, allowing garbage collector implementations that require write
5743 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5744
5745<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5746<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5747 object to store it to, and the third is the address of the field of Obj to
5748 store to. If the runtime does not require a pointer to the object, Obj may
5749 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5750
5751<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5753 instruction, but may be replaced with substantially more complex code by the
5754 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5755 may only be used in a function which <a href="#gc">specifies a GC
5756 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5757
5758</div>
5759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760<!-- ======================================================================= -->
5761<div class="doc_subsection">
5762 <a name="int_codegen">Code Generator Intrinsics</a>
5763</div>
5764
5765<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5766
5767<p>These intrinsics are provided by LLVM to expose special features that may
5768 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5769
5770</div>
5771
5772<!-- _______________________________________________________________________ -->
5773<div class="doc_subsubsection">
5774 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5775</div>
5776
5777<div class="doc_text">
5778
5779<h5>Syntax:</h5>
5780<pre>
5781 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5782</pre>
5783
5784<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5785<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5786 target-specific value indicating the return address of the current function
5787 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5788
5789<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5790<p>The argument to this intrinsic indicates which function to return the address
5791 for. Zero indicates the calling function, one indicates its caller, etc.
5792 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5793
5794<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5795<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5796 indicating the return address of the specified call frame, or zero if it
5797 cannot be identified. The value returned by this intrinsic is likely to be
5798 incorrect or 0 for arguments other than zero, so it should only be used for
5799 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5800
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5801<p>Note that calling this intrinsic does not prevent function inlining or other
5802 aggressive transformations, so the value returned may not be that of the
5803 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805</div>
5806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5807<!-- _______________________________________________________________________ -->
5808<div class="doc_subsubsection">
5809 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5810</div>
5811
5812<div class="doc_text">
5813
5814<h5>Syntax:</h5>
5815<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5816 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5817</pre>
5818
5819<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5821 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5822
5823<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5824<p>The argument to this intrinsic indicates which function to return the frame
5825 pointer for. Zero indicates the calling function, one indicates its caller,
5826 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5827
5828<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5829<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5830 indicating the frame address of the specified call frame, or zero if it
5831 cannot be identified. The value returned by this intrinsic is likely to be
5832 incorrect or 0 for arguments other than zero, so it should only be used for
5833 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5834
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5835<p>Note that calling this intrinsic does not prevent function inlining or other
5836 aggressive transformations, so the value returned may not be that of the
5837 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5839</div>
5840
5841<!-- _______________________________________________________________________ -->
5842<div class="doc_subsubsection">
5843 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5844</div>
5845
5846<div class="doc_text">
5847
5848<h5>Syntax:</h5>
5849<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5850 declare i8* @llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5851</pre>
5852
5853<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5854<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5855 of the function stack, for use
5856 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5857 useful for implementing language features like scoped automatic variable
5858 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5859
5860<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5861<p>This intrinsic returns a opaque pointer value that can be passed
5862 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5863 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5864 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5865 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5866 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5867 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5868
5869</div>
5870
5871<!-- _______________________________________________________________________ -->
5872<div class="doc_subsubsection">
5873 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5874</div>
5875
5876<div class="doc_text">
5877
5878<h5>Syntax:</h5>
5879<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]5880 declare void @llvm.stackrestore(i8* %ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5881</pre>
5882
5883<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5884<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5885 the function stack to the state it was in when the
5886 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5887 executed. This is useful for implementing language features like scoped
5888 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5889
5890<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5891<p>See the description
5892 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5893
5894</div>
5895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5896<!-- _______________________________________________________________________ -->
5897<div class="doc_subsubsection">
5898 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5899</div>
5900
5901<div class="doc_text">
5902
5903<h5>Syntax:</h5>
5904<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5905 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5906</pre>
5907
5908<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5909<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5910 insert a prefetch instruction if supported; otherwise, it is a noop.
5911 Prefetches have no effect on the behavior of the program but can change its
5912 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5913
5914<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5915<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5916 specifier determining if the fetch should be for a read (0) or write (1),
5917 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5918 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5919 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5920
5921<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5922<p>This intrinsic does not modify the behavior of the program. In particular,
5923 prefetches cannot trap and do not produce a value. On targets that support
5924 this intrinsic, the prefetch can provide hints to the processor cache for
5925 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5926
5927</div>
5928
5929<!-- _______________________________________________________________________ -->
5930<div class="doc_subsubsection">
5931 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5932</div>
5933
5934<div class="doc_text">
5935
5936<h5>Syntax:</h5>
5937<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5938 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5939</pre>
5940
5941<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5942<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5943 Counter (PC) in a region of code to simulators and other tools. The method
5944 is target specific, but it is expected that the marker will use exported
5945 symbols to transmit the PC of the marker. The marker makes no guarantees
5946 that it will remain with any specific instruction after optimizations. It is
5947 possible that the presence of a marker will inhibit optimizations. The
5948 intended use is to be inserted after optimizations to allow correlations of
5949 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5950
5951<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5952<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5953
5954<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5955<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]5956 not support this intrinsic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5957
5958</div>
5959
5960<!-- _______________________________________________________________________ -->
5961<div class="doc_subsubsection">
5962 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5963</div>
5964
5965<div class="doc_text">
5966
5967<h5>Syntax:</h5>
5968<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]5969 declare i64 @llvm.readcyclecounter()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5970</pre>
5971
5972<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5973<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5974 counter register (or similar low latency, high accuracy clocks) on those
5975 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5976 should map to RPCC. As the backing counters overflow quickly (on the order
5977 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5978
5979<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5980<p>When directly supported, reading the cycle counter should not modify any
5981 memory. Implementations are allowed to either return a application specific
5982 value or a system wide value. On backends without support, this is lowered
5983 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5984
5985</div>
5986
5987<!-- ======================================================================= -->
5988<div class="doc_subsection">
5989 <a name="int_libc">Standard C Library Intrinsics</a>
5990</div>
5991
5992<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5993
5994<p>LLVM provides intrinsics for a few important standard C library functions.
5995 These intrinsics allow source-language front-ends to pass information about
5996 the alignment of the pointer arguments to the code generator, providing
5997 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5998
5999</div>
6000
6001<!-- _______________________________________________________________________ -->
6002<div class="doc_subsubsection">
6003 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
6004</div>
6005
6006<div class="doc_text">
6007
6008<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6009<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang238462c2010-04-07 06:35:53 +0000[diff] [blame]6010 integer bit width and for different address spaces. Not all targets support
6011 all bit widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6012
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6014 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6015 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6016 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6017 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6018</pre>
6019
6020<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6021<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6022 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6023
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6024<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6025 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6026 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6027
6028<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6029
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6030<p>The first argument is a pointer to the destination, the second is a pointer
6031 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6032 number of bytes to copy, the fourth argument is the alignment of the
6033 source and destination locations, and the fifth is a boolean indicating a
6034 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6035
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6036<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6037 then the caller guarantees that both the source and destination pointers are
6038 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6039
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6040<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6041 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6042 The detailed access behavior is not very cleanly specified and it is unwise
6043 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6044
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6045<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6046
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6047<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6048 source location to the destination location, which are not allowed to
6049 overlap. It copies "len" bytes of memory over. If the argument is known to
6050 be aligned to some boundary, this can be specified as the fourth argument,
6051 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6053</div>
6054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6055<!-- _______________________________________________________________________ -->
6056<div class="doc_subsubsection">
6057 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
6058</div>
6059
6060<div class="doc_text">
6061
6062<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6063<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang238462c2010-04-07 06:35:53 +0000[diff] [blame]6064 width and for different address space. Not all targets support all bit
6065 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6067<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6068 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6069 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6070 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6071 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6072</pre>
6073
6074<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6076 source location to the destination location. It is similar to the
6077 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6078 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6079
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6080<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6081 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6082 and the pointers can be in specified address spaces.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6083
6084<h5>Arguments:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6085
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6086<p>The first argument is a pointer to the destination, the second is a pointer
6087 to the source. The third argument is an integer argument specifying the
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6088 number of bytes to copy, the fourth argument is the alignment of the
6089 source and destination locations, and the fifth is a boolean indicating a
6090 volatile access.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6091
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6092<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6093 then the caller guarantees that the source and destination pointers are
6094 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6095
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6096<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6097 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
6098 The detailed access behavior is not very cleanly specified and it is unwise
6099 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6100
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6101<h5>Semantics:</h5>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6102
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6103<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
6104 source location to the destination location, which may overlap. It copies
6105 "len" bytes of memory over. If the argument is known to be aligned to some
6106 boundary, this can be specified as the fourth argument, otherwise it should
6107 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6109</div>
6110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6111<!-- _______________________________________________________________________ -->
6112<div class="doc_subsubsection">
6113 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
6114</div>
6115
6116<div class="doc_text">
6117
6118<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]6119<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Mon P Wang238462c2010-04-07 06:35:53 +0000[diff] [blame]6120 width and for different address spaces. Not all targets support all bit
6121 widths however.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6123<pre>
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6124 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6125 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanecfb95c2010-05-28 17:13:49 +0000[diff] [blame]6126 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattnerc0dfafe2010-04-08 00:54:34 +0000[diff] [blame]6127 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6128</pre>
6129
6130<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
6132 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6133
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6134<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6135 intrinsic does not return a value, takes extra alignment/volatile arguments,
6136 and the destination can be in an arbitrary address space.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6137
6138<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6139<p>The first argument is a pointer to the destination to fill, the second is the
6140 byte value to fill it with, the third argument is an integer argument
6141 specifying the number of bytes to fill, and the fourth argument is the known
6142 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6143
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]6144<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6145 then the caller guarantees that the destination pointer is aligned to that
6146 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6147
Jeffrey Yasskin6dc467f2010-04-26 21:21:24 +0000[diff] [blame]6148<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6149 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
6150 The detailed access behavior is not very cleanly specified and it is unwise
6151 to depend on it.</p>
Chris Lattner5aa5aab2010-04-08 00:53:57 +0000[diff] [blame]6152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6153<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6154<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
6155 at the destination location. If the argument is known to be aligned to some
6156 boundary, this can be specified as the fourth argument, otherwise it should
6157 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6159</div>
6160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6161<!-- _______________________________________________________________________ -->
6162<div class="doc_subsubsection">
6163 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
6164</div>
6165
6166<div class="doc_text">
6167
6168<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6169<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
6170 floating point or vector of floating point type. Not all targets support all
6171 types however.</p>
6172
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6173<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6174 declare float @llvm.sqrt.f32(float %Val)
6175 declare double @llvm.sqrt.f64(double %Val)
6176 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
6177 declare fp128 @llvm.sqrt.f128(fp128 %Val)
6178 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6179</pre>
6180
6181<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6182<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
6183 returning the same value as the libm '<tt>sqrt</tt>' functions would.
6184 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
6185 behavior for negative numbers other than -0.0 (which allows for better
6186 optimization, because there is no need to worry about errno being
6187 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6188
6189<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6190<p>The argument and return value are floating point numbers of the same
6191 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6192
6193<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6194<p>This function returns the sqrt of the specified operand if it is a
6195 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6197</div>
6198
6199<!-- _______________________________________________________________________ -->
6200<div class="doc_subsubsection">
6201 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
6202</div>
6203
6204<div class="doc_text">
6205
6206<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6207<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
6208 floating point or vector of floating point type. Not all targets support all
6209 types however.</p>
6210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6211<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]6212 declare float @llvm.powi.f32(float %Val, i32 %power)
6213 declare double @llvm.powi.f64(double %Val, i32 %power)
6214 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
6215 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
6216 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6217</pre>
6218
6219<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6220<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
6221 specified (positive or negative) power. The order of evaluation of
6222 multiplications is not defined. When a vector of floating point type is
6223 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6224
6225<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6226<p>The second argument is an integer power, and the first is a value to raise to
6227 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6228
6229<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6230<p>This function returns the first value raised to the second power with an
6231 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6233</div>
6234
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6235<!-- _______________________________________________________________________ -->
6236<div class="doc_subsubsection">
6237 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
6238</div>
6239
6240<div class="doc_text">
6241
6242<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6243<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
6244 floating point or vector of floating point type. Not all targets support all
6245 types however.</p>
6246
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6247<pre>
6248 declare float @llvm.sin.f32(float %Val)
6249 declare double @llvm.sin.f64(double %Val)
6250 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
6251 declare fp128 @llvm.sin.f128(fp128 %Val)
6252 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
6253</pre>
6254
6255<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6256<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6257
6258<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6259<p>The argument and return value are floating point numbers of the same
6260 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6261
6262<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6263<p>This function returns the sine of the specified operand, returning the same
6264 values as the libm <tt>sin</tt> functions would, and handles error conditions
6265 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6266
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6267</div>
6268
6269<!-- _______________________________________________________________________ -->
6270<div class="doc_subsubsection">
6271 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
6272</div>
6273
6274<div class="doc_text">
6275
6276<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6277<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
6278 floating point or vector of floating point type. Not all targets support all
6279 types however.</p>
6280
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6281<pre>
6282 declare float @llvm.cos.f32(float %Val)
6283 declare double @llvm.cos.f64(double %Val)
6284 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
6285 declare fp128 @llvm.cos.f128(fp128 %Val)
6286 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
6287</pre>
6288
6289<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6290<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6291
6292<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6293<p>The argument and return value are floating point numbers of the same
6294 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6295
6296<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6297<p>This function returns the cosine of the specified operand, returning the same
6298 values as the libm <tt>cos</tt> functions would, and handles error conditions
6299 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6300
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6301</div>
6302
6303<!-- _______________________________________________________________________ -->
6304<div class="doc_subsubsection">
6305 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6306</div>
6307
6308<div class="doc_text">
6309
6310<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6311<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6312 floating point or vector of floating point type. Not all targets support all
6313 types however.</p>
6314
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6315<pre>
6316 declare float @llvm.pow.f32(float %Val, float %Power)
6317 declare double @llvm.pow.f64(double %Val, double %Power)
6318 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6319 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6320 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6321</pre>
6322
6323<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6324<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6325 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6326
6327<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6328<p>The second argument is a floating point power, and the first is a value to
6329 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6330
6331<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6332<p>This function returns the first value raised to the second power, returning
6333 the same values as the libm <tt>pow</tt> functions would, and handles error
6334 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6335
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6336</div>
6337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6338<!-- ======================================================================= -->
6339<div class="doc_subsection">
6340 <a name="int_manip">Bit Manipulation Intrinsics</a>
6341</div>
6342
6343<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6344
6345<p>LLVM provides intrinsics for a few important bit manipulation operations.
6346 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6347
6348</div>
6349
6350<!-- _______________________________________________________________________ -->
6351<div class="doc_subsubsection">
6352 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6353</div>
6354
6355<div class="doc_text">
6356
6357<h5>Syntax:</h5>
6358<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6359 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6361<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6362 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6363 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6364 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6365</pre>
6366
6367<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6368<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6369 values with an even number of bytes (positive multiple of 16 bits). These
6370 are useful for performing operations on data that is not in the target's
6371 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6372
6373<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6374<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6375 and low byte of the input i16 swapped. Similarly,
6376 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6377 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6378 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6379 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6380 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6381 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6382
6383</div>
6384
6385<!-- _______________________________________________________________________ -->
6386<div class="doc_subsubsection">
6387 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6388</div>
6389
6390<div class="doc_text">
6391
6392<h5>Syntax:</h5>
6393<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6394 width. Not all targets support all bit widths however.</p>
6395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6396<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6397 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6398 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6399 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6400 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6401 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6402</pre>
6403
6404<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6405<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6406 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6407
6408<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6409<p>The only argument is the value to be counted. The argument may be of any
6410 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6411
6412<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6413<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6415</div>
6416
6417<!-- _______________________________________________________________________ -->
6418<div class="doc_subsubsection">
6419 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6420</div>
6421
6422<div class="doc_text">
6423
6424<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6425<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6426 integer bit width. Not all targets support all bit widths however.</p>
6427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6428<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6429 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6430 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6431 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6432 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6433 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6434</pre>
6435
6436<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6437<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6438 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6439
6440<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6441<p>The only argument is the value to be counted. The argument may be of any
6442 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6443
6444<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6445<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6446 zeros in a variable. If the src == 0 then the result is the size in bits of
6447 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6449</div>
6450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6451<!-- _______________________________________________________________________ -->
6452<div class="doc_subsubsection">
6453 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6454</div>
6455
6456<div class="doc_text">
6457
6458<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6459<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6460 integer bit width. Not all targets support all bit widths however.</p>
6461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6462<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6463 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6464 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6465 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6466 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6467 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6468</pre>
6469
6470<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6472 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6473
6474<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6475<p>The only argument is the value to be counted. The argument may be of any
6476 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6477
6478<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6479<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6480 zeros in a variable. If the src == 0 then the result is the size in bits of
6481 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6483</div>
6484
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6485<!-- ======================================================================= -->
6486<div class="doc_subsection">
6487 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6488</div>
6489
6490<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6491
6492<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6493
6494</div>
6495
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6496<!-- _______________________________________________________________________ -->
6497<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6498 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6499</div>
6500
6501<div class="doc_text">
6502
6503<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6504<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6505 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6506
6507<pre>
6508 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6509 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6510 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6511</pre>
6512
6513<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6514<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6515 a signed addition of the two arguments, and indicate whether an overflow
6516 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6517
6518<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6519<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6520 be of integer types of any bit width, but they must have the same bit
6521 width. The second element of the result structure must be of
6522 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6523 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6524
6525<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6526<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6527 a signed addition of the two variables. They return a structure &mdash; the
6528 first element of which is the signed summation, and the second element of
6529 which is a bit specifying if the signed summation resulted in an
6530 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6531
6532<h5>Examples:</h5>
6533<pre>
6534 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6535 %sum = extractvalue {i32, i1} %res, 0
6536 %obit = extractvalue {i32, i1} %res, 1
6537 br i1 %obit, label %overflow, label %normal
6538</pre>
6539
6540</div>
6541
6542<!-- _______________________________________________________________________ -->
6543<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6544 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6545</div>
6546
6547<div class="doc_text">
6548
6549<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6550<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6551 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6552
6553<pre>
6554 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6555 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6556 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6557</pre>
6558
6559<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6560<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6561 an unsigned addition of the two arguments, and indicate whether a carry
6562 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6563
6564<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6565<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6566 be of integer types of any bit width, but they must have the same bit
6567 width. The second element of the result structure must be of
6568 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6569 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6570
6571<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6572<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6573 an unsigned addition of the two arguments. They return a structure &mdash;
6574 the first element of which is the sum, and the second element of which is a
6575 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6576
6577<h5>Examples:</h5>
6578<pre>
6579 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6580 %sum = extractvalue {i32, i1} %res, 0
6581 %obit = extractvalue {i32, i1} %res, 1
6582 br i1 %obit, label %carry, label %normal
6583</pre>
6584
6585</div>
6586
6587<!-- _______________________________________________________________________ -->
6588<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6589 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6590</div>
6591
6592<div class="doc_text">
6593
6594<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6595<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6596 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6597
6598<pre>
6599 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6600 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6601 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6602</pre>
6603
6604<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6605<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6606 a signed subtraction of the two arguments, and indicate whether an overflow
6607 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6608
6609<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6610<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6611 be of integer types of any bit width, but they must have the same bit
6612 width. The second element of the result structure must be of
6613 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6614 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6615
6616<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6617<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6618 a signed subtraction of the two arguments. They return a structure &mdash;
6619 the first element of which is the subtraction, and the second element of
6620 which is a bit specifying if the signed subtraction resulted in an
6621 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6622
6623<h5>Examples:</h5>
6624<pre>
6625 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6626 %sum = extractvalue {i32, i1} %res, 0
6627 %obit = extractvalue {i32, i1} %res, 1
6628 br i1 %obit, label %overflow, label %normal
6629</pre>
6630
6631</div>
6632
6633<!-- _______________________________________________________________________ -->
6634<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6635 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6636</div>
6637
6638<div class="doc_text">
6639
6640<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6641<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6642 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6643
6644<pre>
6645 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6646 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6647 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6648</pre>
6649
6650<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6651<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6652 an unsigned subtraction of the two arguments, and indicate whether an
6653 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6654
6655<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6656<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6657 be of integer types of any bit width, but they must have the same bit
6658 width. The second element of the result structure must be of
6659 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6660 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6661
6662<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6663<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6664 an unsigned subtraction of the two arguments. They return a structure &mdash;
6665 the first element of which is the subtraction, and the second element of
6666 which is a bit specifying if the unsigned subtraction resulted in an
6667 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6668
6669<h5>Examples:</h5>
6670<pre>
6671 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6672 %sum = extractvalue {i32, i1} %res, 0
6673 %obit = extractvalue {i32, i1} %res, 1
6674 br i1 %obit, label %overflow, label %normal
6675</pre>
6676
6677</div>
6678
6679<!-- _______________________________________________________________________ -->
6680<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6681 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6682</div>
6683
6684<div class="doc_text">
6685
6686<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6687<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6688 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6689
6690<pre>
6691 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6692 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6693 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6694</pre>
6695
6696<h5>Overview:</h5>
6697
6698<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6699 a signed multiplication of the two arguments, and indicate whether an
6700 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6701
6702<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6703<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6704 be of integer types of any bit width, but they must have the same bit
6705 width. The second element of the result structure must be of
6706 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6707 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6708
6709<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6710<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6711 a signed multiplication of the two arguments. They return a structure &mdash;
6712 the first element of which is the multiplication, and the second element of
6713 which is a bit specifying if the signed multiplication resulted in an
6714 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6715
6716<h5>Examples:</h5>
6717<pre>
6718 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6719 %sum = extractvalue {i32, i1} %res, 0
6720 %obit = extractvalue {i32, i1} %res, 1
6721 br i1 %obit, label %overflow, label %normal
6722</pre>
6723
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6724</div>
6725
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6726<!-- _______________________________________________________________________ -->
6727<div class="doc_subsubsection">
6728 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6729</div>
6730
6731<div class="doc_text">
6732
6733<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6734<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6735 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6736
6737<pre>
6738 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6739 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6740 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6741</pre>
6742
6743<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6744<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6745 a unsigned multiplication of the two arguments, and indicate whether an
6746 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6747
6748<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6749<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6750 be of integer types of any bit width, but they must have the same bit
6751 width. The second element of the result structure must be of
6752 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6753 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6754
6755<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6756<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6757 an unsigned multiplication of the two arguments. They return a structure
6758 &mdash; the first element of which is the multiplication, and the second
6759 element of which is a bit specifying if the unsigned multiplication resulted
6760 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6761
6762<h5>Examples:</h5>
6763<pre>
6764 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6765 %sum = extractvalue {i32, i1} %res, 0
6766 %obit = extractvalue {i32, i1} %res, 1
6767 br i1 %obit, label %overflow, label %normal
6768</pre>
6769
6770</div>
6771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6772<!-- ======================================================================= -->
6773<div class="doc_subsection">
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6774 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
6775</div>
6776
6777<div class="doc_text">
6778
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6779<p>Half precision floating point is a storage-only format. This means that it is
6780 a dense encoding (in memory) but does not support computation in the
6781 format.</p>
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6782
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6783<p>This means that code must first load the half-precision floating point
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6784 value as an i16, then convert it to float with <a
6785 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
6786 Computation can then be performed on the float value (including extending to
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6787 double etc). To store the value back to memory, it is first converted to
6788 float if needed, then converted to i16 with
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6789 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
6790 storing as an i16 value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6791</div>
6792
6793<!-- _______________________________________________________________________ -->
6794<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6795 <a name="int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6796</div>
6797
6798<div class="doc_text">
6799
6800<h5>Syntax:</h5>
6801<pre>
6802 declare i16 @llvm.convert.to.fp16(f32 %a)
6803</pre>
6804
6805<h5>Overview:</h5>
6806<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6807 a conversion from single precision floating point format to half precision
6808 floating point format.</p>
6809
6810<h5>Arguments:</h5>
6811<p>The intrinsic function contains single argument - the value to be
6812 converted.</p>
6813
6814<h5>Semantics:</h5>
6815<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
6816 a conversion from single precision floating point format to half precision
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6817 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6818 contains the converted number.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6819
6820<h5>Examples:</h5>
6821<pre>
6822 %res = call i16 @llvm.convert.to.fp16(f32 %a)
6823 store i16 %res, i16* @x, align 2
6824</pre>
6825
6826</div>
6827
6828<!-- _______________________________________________________________________ -->
6829<div class="doc_subsubsection">
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6830 <a name="int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6831</div>
6832
6833<div class="doc_text">
6834
6835<h5>Syntax:</h5>
6836<pre>
6837 declare f32 @llvm.convert.from.fp16(i16 %a)
6838</pre>
6839
6840<h5>Overview:</h5>
6841<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
6842 a conversion from half precision floating point format to single precision
6843 floating point format.</p>
6844
6845<h5>Arguments:</h5>
6846<p>The intrinsic function contains single argument - the value to be
6847 converted.</p>
6848
6849<h5>Semantics:</h5>
6850<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattnere5969c62010-03-15 04:12:21 +0000[diff] [blame]6851 conversion from half single precision floating point format to single
Chris Lattnerebc48e52010-03-14 23:03:31 +0000[diff] [blame]6852 precision floating point format. The input half-float value is represented by
6853 an <tt>i16</tt> value.</p>
Anton Korobeynikov8c98a892010-03-14 18:42:47 +0000[diff] [blame]6854
6855<h5>Examples:</h5>
6856<pre>
6857 %a = load i16* @x, align 2
6858 %res = call f32 @llvm.convert.from.fp16(i16 %a)
6859</pre>
6860
6861</div>
6862
6863<!-- ======================================================================= -->
6864<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6865 <a name="int_debugger">Debugger Intrinsics</a>
6866</div>
6867
6868<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6869
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6870<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6871 prefix), are described in
6872 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6873 Level Debugging</a> document.</p>
6874
6875</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6876
6877<!-- ======================================================================= -->
6878<div class="doc_subsection">
6879 <a name="int_eh">Exception Handling Intrinsics</a>
6880</div>
6881
6882<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6883
6884<p>The LLVM exception handling intrinsics (which all start with
6885 <tt>llvm.eh.</tt> prefix), are described in
6886 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6887 Handling</a> document.</p>
6888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6889</div>
6890
6891<!-- ======================================================================= -->
6892<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6893 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6894</div>
6895
6896<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6897
6898<p>This intrinsic makes it possible to excise one parameter, marked with
Dan Gohmanbd2f9ba2010-07-02 23:18:08 +0000[diff] [blame]6899 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
6900 The result is a callable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6901 function pointer lacking the nest parameter - the caller does not need to
6902 provide a value for it. Instead, the value to use is stored in advance in a
6903 "trampoline", a block of memory usually allocated on the stack, which also
6904 contains code to splice the nest value into the argument list. This is used
6905 to implement the GCC nested function address extension.</p>
6906
6907<p>For example, if the function is
6908 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6909 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6910 follows:</p>
6911
Benjamin Kramer783e7f92010-07-13 12:26:09 +0000[diff] [blame]6912<pre class="doc_code">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6913 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6914 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6915 %p = call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval)
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6916 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6917</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6918
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]6919<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
6920 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6921
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6922</div>
6923
6924<!-- _______________________________________________________________________ -->
6925<div class="doc_subsubsection">
6926 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6927</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6928
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6929<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6930
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6931<h5>Syntax:</h5>
6932<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6933 declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6934</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6935
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6936<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6937<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6938 function pointer suitable for executing it.</p>
6939
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6940<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6941<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6942 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6943 sufficiently aligned block of memory; this memory is written to by the
6944 intrinsic. Note that the size and the alignment are target-specific - LLVM
6945 currently provides no portable way of determining them, so a front-end that
6946 generates this intrinsic needs to have some target-specific knowledge.
6947 The <tt>func</tt> argument must hold a function bitcast to
6948 an <tt>i8*</tt>.</p>
6949
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6950<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6951<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6952 dependent code, turning it into a function. A pointer to this function is
6953 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6954 function pointer type</a> before being called. The new function's signature
6955 is the same as that of <tt>func</tt> with any arguments marked with
6956 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6957 is allowed, and it must be of pointer type. Calling the new function is
6958 equivalent to calling <tt>func</tt> with the same argument list, but
6959 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6960 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6961 by <tt>tramp</tt> is modified, then the effect of any later call to the
6962 returned function pointer is undefined.</p>
6963
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6964</div>
6965
6966<!-- ======================================================================= -->
6967<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6968 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6969</div>
6970
6971<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6972
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6973<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6974 hardware constructs for atomic operations and memory synchronization. This
6975 provides an interface to the hardware, not an interface to the programmer. It
6976 is aimed at a low enough level to allow any programming models or APIs
6977 (Application Programming Interfaces) which need atomic behaviors to map
6978 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6979 hardware provides a "universal IR" for source languages, it also provides a
6980 starting point for developing a "universal" atomic operation and
6981 synchronization IR.</p>
6982
6983<p>These do <em>not</em> form an API such as high-level threading libraries,
6984 software transaction memory systems, atomic primitives, and intrinsic
6985 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6986 application libraries. The hardware interface provided by LLVM should allow
6987 a clean implementation of all of these APIs and parallel programming models.
6988 No one model or paradigm should be selected above others unless the hardware
6989 itself ubiquitously does so.</p>
6990
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6991</div>
6992
6993<!-- _______________________________________________________________________ -->
6994<div class="doc_subsubsection">
6995 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6996</div>
6997<div class="doc_text">
6998<h5>Syntax:</h5>
6999<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7000 declare void @llvm.memory.barrier(i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;, i1 &lt;device&gt;)
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7001</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7002
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7003<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7004<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
7005 specific pairs of memory access types.</p>
7006
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7007<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7008<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
7009 The first four arguments enables a specific barrier as listed below. The
Dan Gohman22dc6682010-03-01 17:41:39 +0000[diff] [blame]7010 fifth argument specifies that the barrier applies to io or device or uncached
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7011 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7012
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7013<ul>
7014 <li><tt>ll</tt>: load-load barrier</li>
7015 <li><tt>ls</tt>: load-store barrier</li>
7016 <li><tt>sl</tt>: store-load barrier</li>
7017 <li><tt>ss</tt>: store-store barrier</li>
7018 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
7019</ul>
7020
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7021<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7022<p>This intrinsic causes the system to enforce some ordering constraints upon
7023 the loads and stores of the program. This barrier does not
7024 indicate <em>when</em> any events will occur, it only enforces
7025 an <em>order</em> in which they occur. For any of the specified pairs of load
7026 and store operations (f.ex. load-load, or store-load), all of the first
7027 operations preceding the barrier will complete before any of the second
7028 operations succeeding the barrier begin. Specifically the semantics for each
7029 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7030
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7031<ul>
7032 <li><tt>ll</tt>: All loads before the barrier must complete before any load
7033 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7034 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7035 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7036 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7037 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7038 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7039 load after the barrier begins.</li>
7040</ul>
7041
7042<p>These semantics are applied with a logical "and" behavior when more than one
7043 is enabled in a single memory barrier intrinsic.</p>
7044
7045<p>Backends may implement stronger barriers than those requested when they do
7046 not support as fine grained a barrier as requested. Some architectures do
7047 not need all types of barriers and on such architectures, these become
7048 noops.</p>
7049
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7050<h5>Example:</h5>
7051<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7052%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7053%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7054 store i32 4, %ptr
7055
7056%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7057 call void @llvm.memory.barrier(i1 false, i1 true, i1 false, i1 false)
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7058 <i>; guarantee the above finishes</i>
7059 store i32 8, %ptr <i>; before this begins</i>
7060</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7061
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7062</div>
7063
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7064<!-- _______________________________________________________________________ -->
7065<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7066 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7067</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7068
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7069<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7070
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7071<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7072<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
7073 any integer bit width and for different address spaces. Not all targets
7074 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7075
7076<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7077 declare i8 @llvm.atomic.cmp.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt;)
7078 declare i16 @llvm.atomic.cmp.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt;)
7079 declare i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt;)
7080 declare i64 @llvm.atomic.cmp.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt;)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7081</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7082
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7083<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7084<p>This loads a value in memory and compares it to a given value. If they are
7085 equal, it stores a new value into the memory.</p>
7086
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7087<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7088<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
7089 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
7090 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
7091 this integer type. While any bit width integer may be used, targets may only
7092 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7093
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7094<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7095<p>This entire intrinsic must be executed atomically. It first loads the value
7096 in memory pointed to by <tt>ptr</tt> and compares it with the
7097 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
7098 memory. The loaded value is yielded in all cases. This provides the
7099 equivalent of an atomic compare-and-swap operation within the SSA
7100 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7101
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7102<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7103<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7104%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7105%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7106 store i32 4, %ptr
7107
7108%val1 = add i32 4, 4
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7109%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 4, %val1)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7110 <i>; yields {i32}:result1 = 4</i>
7111%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7112%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7113
7114%val2 = add i32 1, 1
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7115%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32(i32* %ptr, i32 5, %val2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7116 <i>; yields {i32}:result2 = 8</i>
7117%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
7118
7119%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
7120</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7121
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7122</div>
7123
7124<!-- _______________________________________________________________________ -->
7125<div class="doc_subsubsection">
7126 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
7127</div>
7128<div class="doc_text">
7129<h5>Syntax:</h5>
7130
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7131<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
7132 integer bit width. Not all targets support all bit widths however.</p>
7133
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7134<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7135 declare i8 @llvm.atomic.swap.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;val&gt;)
7136 declare i16 @llvm.atomic.swap.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;val&gt;)
7137 declare i32 @llvm.atomic.swap.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;val&gt;)
7138 declare i64 @llvm.atomic.swap.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;val&gt;)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7139</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7140
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7141<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7142<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
7143 the value from memory. It then stores the value in <tt>val</tt> in the memory
7144 at <tt>ptr</tt>.</p>
7145
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7146<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7147<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
7148 the <tt>val</tt> argument and the result must be integers of the same bit
7149 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
7150 integer type. The targets may only lower integer representations they
7151 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7152
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7153<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7154<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
7155 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
7156 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7157
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7158<h5>Examples:</h5>
7159<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7160%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7161%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7162 store i32 4, %ptr
7163
7164%val1 = add i32 4, 4
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7165%result1 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val1)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7166 <i>; yields {i32}:result1 = 4</i>
7167%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
7168%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
7169
7170%val2 = add i32 1, 1
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7171%result2 = call i32 @llvm.atomic.swap.i32.p0i32(i32* %ptr, i32 %val2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7172 <i>; yields {i32}:result2 = 8</i>
7173
7174%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
7175%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
7176</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7177
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7178</div>
7179
7180<!-- _______________________________________________________________________ -->
7181<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7182 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7183
7184</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7185
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7186<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7187
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7188<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7189<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
7190 any integer bit width. Not all targets support all bit widths however.</p>
7191
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7192<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7193 declare i8 @llvm.atomic.load.add.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7194 declare i16 @llvm.atomic.load.add.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7195 declare i32 @llvm.atomic.load.add.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7196 declare i64 @llvm.atomic.load.add.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7197</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7198
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7199<h5>Overview:</h5>
7200<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
7201 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7202
7203<h5>Arguments:</h5>
7204<p>The intrinsic takes two arguments, the first a pointer to an integer value
7205 and the second an integer value. The result is also an integer value. These
7206 integer types can have any bit width, but they must all have the same bit
7207 width. The targets may only lower integer representations they support.</p>
7208
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7209<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7210<p>This intrinsic does a series of operations atomically. It first loads the
7211 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
7212 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7213
7214<h5>Examples:</h5>
7215<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7216%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7217%ptr = bitcast i8* %mallocP to i32*
7218 store i32 4, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7219%result1 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 4)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7220 <i>; yields {i32}:result1 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7221%result2 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 2)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7222 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7223%result3 = call i32 @llvm.atomic.load.add.i32.p0i32(i32* %ptr, i32 5)
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7224 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7225%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7226</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7227
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]7228</div>
7229
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7230<!-- _______________________________________________________________________ -->
7231<div class="doc_subsubsection">
7232 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
7233
7234</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7235
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7236<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7237
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7238<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7239<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
7240 any integer bit width and for different address spaces. Not all targets
7241 support all bit widths however.</p>
7242
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7243<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7244 declare i8 @llvm.atomic.load.sub.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7245 declare i16 @llvm.atomic.load.sub.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7246 declare i32 @llvm.atomic.load.sub.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7247 declare i64 @llvm.atomic.load.sub.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7248</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7249
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7250<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7251<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7252 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
7253
7254<h5>Arguments:</h5>
7255<p>The intrinsic takes two arguments, the first a pointer to an integer value
7256 and the second an integer value. The result is also an integer value. These
7257 integer types can have any bit width, but they must all have the same bit
7258 width. The targets may only lower integer representations they support.</p>
7259
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7260<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7261<p>This intrinsic does a series of operations atomically. It first loads the
7262 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
7263 result to <tt>ptr</tt>. It yields the original value stored
7264 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7265
7266<h5>Examples:</h5>
7267<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7268%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7269%ptr = bitcast i8* %mallocP to i32*
7270 store i32 8, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7271%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 4)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7272 <i>; yields {i32}:result1 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7273%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 2)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7274 <i>; yields {i32}:result2 = 4</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7275%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %ptr, i32 5)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7276 <i>; yields {i32}:result3 = 2</i>
7277%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
7278</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7279
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7280</div>
7281
7282<!-- _______________________________________________________________________ -->
7283<div class="doc_subsubsection">
7284 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
7285 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
7286 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
7287 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7288</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7289
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7290<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7291
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7292<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7293<p>These are overloaded intrinsics. You can
7294 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
7295 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
7296 bit width and for different address spaces. Not all targets support all bit
7297 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7298
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7299<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7300 declare i8 @llvm.atomic.load.and.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7301 declare i16 @llvm.atomic.load.and.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7302 declare i32 @llvm.atomic.load.and.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7303 declare i64 @llvm.atomic.load.and.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7304</pre>
7305
7306<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7307 declare i8 @llvm.atomic.load.or.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7308 declare i16 @llvm.atomic.load.or.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7309 declare i32 @llvm.atomic.load.or.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7310 declare i64 @llvm.atomic.load.or.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7311</pre>
7312
7313<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7314 declare i8 @llvm.atomic.load.nand.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7315 declare i16 @llvm.atomic.load.nand.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7316 declare i32 @llvm.atomic.load.nand.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7317 declare i64 @llvm.atomic.load.nand.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7318</pre>
7319
7320<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7321 declare i8 @llvm.atomic.load.xor.i8.p0i32(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7322 declare i16 @llvm.atomic.load.xor.i16.p0i32(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7323 declare i32 @llvm.atomic.load.xor.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7324 declare i64 @llvm.atomic.load.xor.i64.p0i32(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7325</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7326
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7327<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7328<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
7329 the value stored in memory at <tt>ptr</tt>. It yields the original value
7330 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7331
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7332<h5>Arguments:</h5>
7333<p>These intrinsics take two arguments, the first a pointer to an integer value
7334 and the second an integer value. The result is also an integer value. These
7335 integer types can have any bit width, but they must all have the same bit
7336 width. The targets may only lower integer representations they support.</p>
7337
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7338<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7339<p>These intrinsics does a series of operations atomically. They first load the
7340 value stored at <tt>ptr</tt>. They then do the bitwise
7341 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
7342 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7343
7344<h5>Examples:</h5>
7345<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7346%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7347%ptr = bitcast i8* %mallocP to i32*
7348 store i32 0x0F0F, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7349%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7350 <i>; yields {i32}:result0 = 0x0F0F</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7351%result1 = call i32 @llvm.atomic.load.and.i32.p0i32(i32* %ptr, i32 0xFF)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7352 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7353%result2 = call i32 @llvm.atomic.load.or.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7354 <i>; yields {i32}:result2 = 0xF0</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7355%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32(i32* %ptr, i32 0F)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7356 <i>; yields {i32}:result3 = FF</i>
7357%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
7358</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7359
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7360</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7361
7362<!-- _______________________________________________________________________ -->
7363<div class="doc_subsubsection">
7364 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
7365 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
7366 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
7367 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7368</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7369
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7370<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7371
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7372<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7373<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
7374 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
7375 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
7376 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7377
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7378<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7379 declare i8 @llvm.atomic.load.max.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7380 declare i16 @llvm.atomic.load.max.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7381 declare i32 @llvm.atomic.load.max.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7382 declare i64 @llvm.atomic.load.max.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7383</pre>
7384
7385<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7386 declare i8 @llvm.atomic.load.min.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7387 declare i16 @llvm.atomic.load.min.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7388 declare i32 @llvm.atomic.load.min.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7389 declare i64 @llvm.atomic.load.min.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7390</pre>
7391
7392<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7393 declare i8 @llvm.atomic.load.umax.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7394 declare i16 @llvm.atomic.load.umax.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7395 declare i32 @llvm.atomic.load.umax.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7396 declare i64 @llvm.atomic.load.umax.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7397</pre>
7398
7399<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7400 declare i8 @llvm.atomic.load.umin.i8.p0i8(i8* &lt;ptr&gt;, i8 &lt;delta&gt;)
7401 declare i16 @llvm.atomic.load.umin.i16.p0i16(i16* &lt;ptr&gt;, i16 &lt;delta&gt;)
7402 declare i32 @llvm.atomic.load.umin.i32.p0i32(i32* &lt;ptr&gt;, i32 &lt;delta&gt;)
7403 declare i64 @llvm.atomic.load.umin.i64.p0i64(i64* &lt;ptr&gt;, i64 &lt;delta&gt;)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7404</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7405
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7406<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7407<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7408 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7409 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7410
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7411<h5>Arguments:</h5>
7412<p>These intrinsics take two arguments, the first a pointer to an integer value
7413 and the second an integer value. The result is also an integer value. These
7414 integer types can have any bit width, but they must all have the same bit
7415 width. The targets may only lower integer representations they support.</p>
7416
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7417<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7418<p>These intrinsics does a series of operations atomically. They first load the
7419 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7420 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7421 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7422
7423<h5>Examples:</h5>
7424<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7425%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7426%ptr = bitcast i8* %mallocP to i32*
7427 store i32 7, %ptr
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7428%result0 = call i32 @llvm.atomic.load.min.i32.p0i32(i32* %ptr, i32 -2)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7429 <i>; yields {i32}:result0 = 7</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7430%result1 = call i32 @llvm.atomic.load.max.i32.p0i32(i32* %ptr, i32 8)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7431 <i>; yields {i32}:result1 = -2</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7432%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32(i32* %ptr, i32 10)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7433 <i>; yields {i32}:result2 = 8</i>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7434%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32(i32* %ptr, i32 30)
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7435 <i>; yields {i32}:result3 = 8</i>
7436%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7437</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7438
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7439</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7440
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7441
7442<!-- ======================================================================= -->
7443<div class="doc_subsection">
7444 <a name="int_memorymarkers">Memory Use Markers</a>
7445</div>
7446
7447<div class="doc_text">
7448
7449<p>This class of intrinsics exists to information about the lifetime of memory
7450 objects and ranges where variables are immutable.</p>
7451
7452</div>
7453
7454<!-- _______________________________________________________________________ -->
7455<div class="doc_subsubsection">
7456 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7457</div>
7458
7459<div class="doc_text">
7460
7461<h5>Syntax:</h5>
7462<pre>
7463 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7464</pre>
7465
7466<h5>Overview:</h5>
7467<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7468 object's lifetime.</p>
7469
7470<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7471<p>The first argument is a constant integer representing the size of the
7472 object, or -1 if it is variable sized. The second argument is a pointer to
7473 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7474
7475<h5>Semantics:</h5>
7476<p>This intrinsic indicates that before this point in the code, the value of the
7477 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyf8a5f302009-10-27 16:56:58 +0000[diff] [blame]7478 never be used and has an undefined value. A load from the pointer that
7479 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7480 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7481
7482</div>
7483
7484<!-- _______________________________________________________________________ -->
7485<div class="doc_subsubsection">
7486 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7487</div>
7488
7489<div class="doc_text">
7490
7491<h5>Syntax:</h5>
7492<pre>
7493 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7494</pre>
7495
7496<h5>Overview:</h5>
7497<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7498 object's lifetime.</p>
7499
7500<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7501<p>The first argument is a constant integer representing the size of the
7502 object, or -1 if it is variable sized. The second argument is a pointer to
7503 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7504
7505<h5>Semantics:</h5>
7506<p>This intrinsic indicates that after this point in the code, the value of the
7507 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7508 never be used and has an undefined value. Any stores into the memory object
7509 following this intrinsic may be removed as dead.
7510
7511</div>
7512
7513<!-- _______________________________________________________________________ -->
7514<div class="doc_subsubsection">
7515 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7516</div>
7517
7518<div class="doc_text">
7519
7520<h5>Syntax:</h5>
7521<pre>
7522 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7523</pre>
7524
7525<h5>Overview:</h5>
7526<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7527 a memory object will not change.</p>
7528
7529<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7530<p>The first argument is a constant integer representing the size of the
7531 object, or -1 if it is variable sized. The second argument is a pointer to
7532 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7533
7534<h5>Semantics:</h5>
7535<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7536 the return value, the referenced memory location is constant and
7537 unchanging.</p>
7538
7539</div>
7540
7541<!-- _______________________________________________________________________ -->
7542<div class="doc_subsubsection">
7543 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7544</div>
7545
7546<div class="doc_text">
7547
7548<h5>Syntax:</h5>
7549<pre>
7550 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7551</pre>
7552
7553<h5>Overview:</h5>
7554<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7555 a memory object are mutable.</p>
7556
7557<h5>Arguments:</h5>
7558<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7559 The second argument is a constant integer representing the size of the
7560 object, or -1 if it is variable sized and the third argument is a pointer
7561 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7562
7563<h5>Semantics:</h5>
7564<p>This intrinsic indicates that the memory is mutable again.</p>
7565
7566</div>
7567
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7568<!-- ======================================================================= -->
7569<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7570 <a name="int_general">General Intrinsics</a>
7571</div>
7572
7573<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7574
7575<p>This class of intrinsics is designed to be generic and has no specific
7576 purpose.</p>
7577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7578</div>
7579
7580<!-- _______________________________________________________________________ -->
7581<div class="doc_subsubsection">
7582 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7583</div>
7584
7585<div class="doc_text">
7586
7587<h5>Syntax:</h5>
7588<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7589 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7590</pre>
7591
7592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7593<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7594
7595<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7596<p>The first argument is a pointer to a value, the second is a pointer to a
7597 global string, the third is a pointer to a global string which is the source
7598 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7599
7600<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7601<p>This intrinsic allows annotation of local variables with arbitrary strings.
7602 This can be useful for special purpose optimizations that want to look for
7603 these annotations. These have no other defined use, they are ignored by code
7604 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7606</div>
7607
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7608<!-- _______________________________________________________________________ -->
7609<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7610 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7611</div>
7612
7613<div class="doc_text">
7614
7615<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7616<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7617 any integer bit width.</p>
7618
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7619<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7620 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7621 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7622 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7623 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
7624 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7625</pre>
7626
7627<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7628<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7629
7630<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7631<p>The first argument is an integer value (result of some expression), the
7632 second is a pointer to a global string, the third is a pointer to a global
7633 string which is the source file name, and the last argument is the line
7634 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7635
7636<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7637<p>This intrinsic allows annotations to be put on arbitrary expressions with
7638 arbitrary strings. This can be useful for special purpose optimizations that
7639 want to look for these annotations. These have no other defined use, they
7640 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7641
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7642</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7643
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7644<!-- _______________________________________________________________________ -->
7645<div class="doc_subsubsection">
7646 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7647</div>
7648
7649<div class="doc_text">
7650
7651<h5>Syntax:</h5>
7652<pre>
7653 declare void @llvm.trap()
7654</pre>
7655
7656<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7657<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7658
7659<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7660<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7661
7662<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7663<p>This intrinsics is lowered to the target dependent trap instruction. If the
7664 target does not have a trap instruction, this intrinsic will be lowered to
7665 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7666
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7667</div>
7668
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7669<!-- _______________________________________________________________________ -->
7670<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7671 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7672</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7673
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7674<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7675
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7676<h5>Syntax:</h5>
7677<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7678 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7679</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7680
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7681<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7682<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7683 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7684 ensure that it is placed on the stack before local variables.</p>
7685
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7686<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7687<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7688 arguments. The first argument is the value loaded from the stack
7689 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7690 that has enough space to hold the value of the guard.</p>
7691
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7692<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7693<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7694 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7695 stack. This is to ensure that if a local variable on the stack is
7696 overwritten, it will destroy the value of the guard. When the function exits,
7697 the guard on the stack is checked against the original guard. If they're
7698 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7699 function.</p>
7700
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7701</div>
7702
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7703<!-- _______________________________________________________________________ -->
7704<div class="doc_subsubsection">
7705 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7706</div>
7707
7708<div class="doc_text">
7709
7710<h5>Syntax:</h5>
7711<pre>
Dan Gohmand1ec0af2010-05-28 17:07:41 +0000[diff] [blame]7712 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
7713 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7714</pre>
7715
7716<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7717<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7718 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7719 operation like memcpy will either overflow a buffer that corresponds to
7720 an object, or b) to determine that a runtime check for overflow isn't
7721 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7722 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7723
7724<h5>Arguments:</h5>
7725<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7726 argument is a pointer to or into the <tt>object</tt>. The second argument
7727 is a boolean 0 or 1. This argument determines whether you want the
7728 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7729 1, variables are not allowed.</p>
7730
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7731<h5>Semantics:</h5>
7732<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7733 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7734 (depending on the <tt>type</tt> argument if the size cannot be determined
7735 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7736
7737</div>
7738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7739<!-- *********************************************************************** -->
7740<hr>
7741<address>
7742 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7743 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7744 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7746
7747 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7748 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7749 Last modified: $Date$
7750</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7751
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7752</body>
7753</html>