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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 23f49980e325ac4e698ebc0ed3a0a7e3e298941e / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
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>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]52 </ol>
53 </li>
54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
58 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]64 </ol>
65 </li>
66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
68 <li><a href="#t_array">Array Type</a></li>
69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
71 <li><a href="#t_struct">Structure Type</a></li>
72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
73 <li><a href="#t_vector">Vector Type</a></li>
74 <li><a href="#t_opaque">Opaque Type</a></li>
75 </ol>
76 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 </ol>
79 </li>
80 <li><a href="#constants">Constants</a>
81 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
86 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]87 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]88 </ol>
89 </li>
90 <li><a href="#othervalues">Other Values</a>
91 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]92 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]93 </ol>
94 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]95 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
96 <ol>
97 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]98 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
99 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]100 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
101 Global Variable</a></li>
102 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
103 Global Variable</a></li>
104 </ol>
105 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]106 <li><a href="#instref">Instruction Reference</a>
107 <ol>
108 <li><a href="#terminators">Terminator Instructions</a>
109 <ol>
110 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
111 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
112 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
113 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
114 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
115 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
116 </ol>
117 </li>
118 <li><a href="#binaryops">Binary Operations</a>
119 <ol>
120 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]121 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]122 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
127 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
128 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
129 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
130 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
131 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
132 </ol>
133 </li>
134 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
135 <ol>
136 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
137 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
138 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
139 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
140 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
141 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
142 </ol>
143 </li>
144 <li><a href="#vectorops">Vector Operations</a>
145 <ol>
146 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
147 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
148 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
149 </ol>
150 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]151 <li><a href="#aggregateops">Aggregate Operations</a>
152 <ol>
153 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
154 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
155 </ol>
156 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]157 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
158 <ol>
159 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
160 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
165 </ol>
166 </li>
167 <li><a href="#convertops">Conversion Operations</a>
168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
181 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
191 </ol>
192 </li>
193 </ol>
194 </li>
195 <li><a href="#intrinsics">Intrinsic Functions</a>
196 <ol>
197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
202 </ol>
203 </li>
204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
209 </ol>
210 </li>
211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
220 </ol>
221 </li>
222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]232 </ol>
233 </li>
234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
235 <ol>
236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <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]249 <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]250 </ol>
251 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]285 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]294 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]295 </li>
296 </ol>
297 </li>
298</ol>
299
300<div class="doc_author">
301 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
302 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
303</div>
304
305<!-- *********************************************************************** -->
306<div class="doc_section"> <a name="abstract">Abstract </a></div>
307<!-- *********************************************************************** -->
308
309<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]310
311<p>This document is a reference manual for the LLVM assembly language. LLVM is
312 a Static Single Assignment (SSA) based representation that provides type
313 safety, low-level operations, flexibility, and the capability of representing
314 'all' high-level languages cleanly. It is the common code representation
315 used throughout all phases of the LLVM compilation strategy.</p>
316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]317</div>
318
319<!-- *********************************************************************** -->
320<div class="doc_section"> <a name="introduction">Introduction</a> </div>
321<!-- *********************************************************************** -->
322
323<div class="doc_text">
324
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM code representation is designed to be used in three different forms:
326 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
327 for fast loading by a Just-In-Time compiler), and as a human readable
328 assembly language representation. This allows LLVM to provide a powerful
329 intermediate representation for efficient compiler transformations and
330 analysis, while providing a natural means to debug and visualize the
331 transformations. The three different forms of LLVM are all equivalent. This
332 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]334<p>The LLVM representation aims to be light-weight and low-level while being
335 expressive, typed, and extensible at the same time. It aims to be a
336 "universal IR" of sorts, by being at a low enough level that high-level ideas
337 may be cleanly mapped to it (similar to how microprocessors are "universal
338 IR's", allowing many source languages to be mapped to them). By providing
339 type information, LLVM can be used as the target of optimizations: for
340 example, through pointer analysis, it can be proven that a C automatic
341 variable is never accessed outside of the current function... allowing it to
342 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
344</div>
345
346<!-- _______________________________________________________________________ -->
347<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
348
349<div class="doc_text">
350
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]351<p>It is important to note that this document describes 'well formed' LLVM
352 assembly language. There is a difference between what the parser accepts and
353 what is considered 'well formed'. For example, the following instruction is
354 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355
356<div class="doc_code">
357<pre>
358%x = <a href="#i_add">add</a> i32 1, %x
359</pre>
360</div>
361
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]362<p>...because the definition of <tt>%x</tt> does not dominate all of its
363 uses. The LLVM infrastructure provides a verification pass that may be used
364 to verify that an LLVM module is well formed. This pass is automatically run
365 by the parser after parsing input assembly and by the optimizer before it
366 outputs bitcode. The violations pointed out by the verifier pass indicate
367 bugs in transformation passes or input to the parser.</p>
368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]369</div>
370
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]371<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372
373<!-- *********************************************************************** -->
374<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
375<!-- *********************************************************************** -->
376
377<div class="doc_text">
378
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]379<p>LLVM identifiers come in two basic types: global and local. Global
380 identifiers (functions, global variables) begin with the <tt>'@'</tt>
381 character. Local identifiers (register names, types) begin with
382 the <tt>'%'</tt> character. Additionally, there are three different formats
383 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]384
385<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]386 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]387 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
388 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
389 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
390 other characters in their names can be surrounded with quotes. Special
391 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
392 ASCII code for the character in hexadecimal. In this way, any character
393 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]394
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]395 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]396 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]397
398 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]399 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]400</ol>
401
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]402<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]403 don't need to worry about name clashes with reserved words, and the set of
404 reserved words may be expanded in the future without penalty. Additionally,
405 unnamed identifiers allow a compiler to quickly come up with a temporary
406 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]407
408<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]409 languages. There are keywords for different opcodes
410 ('<tt><a href="#i_add">add</a></tt>',
411 '<tt><a href="#i_bitcast">bitcast</a></tt>',
412 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
413 ('<tt><a href="#t_void">void</a></tt>',
414 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
415 reserved words cannot conflict with variable names, because none of them
416 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]417
418<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]419 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]420
421<p>The easy way:</p>
422
423<div class="doc_code">
424<pre>
425%result = <a href="#i_mul">mul</a> i32 %X, 8
426</pre>
427</div>
428
429<p>After strength reduction:</p>
430
431<div class="doc_code">
432<pre>
433%result = <a href="#i_shl">shl</a> i32 %X, i8 3
434</pre>
435</div>
436
437<p>And the hard way:</p>
438
439<div class="doc_code">
440<pre>
441<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
443%result = <a href="#i_add">add</a> i32 %1, %1
444</pre>
445</div>
446
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]447<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
448 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]449
450<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]451 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]452 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453
454 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]455 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456
457 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458</ol>
459
460<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]461 demonstrating instructions, we will follow an instruction with a comment that
462 defines the type and name of value produced. Comments are shown in italic
463 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]464
465</div>
466
467<!-- *********************************************************************** -->
468<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
469<!-- *********************************************************************** -->
470
471<!-- ======================================================================= -->
472<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
473</div>
474
475<div class="doc_text">
476
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]477<p>LLVM programs are composed of "Module"s, each of which is a translation unit
478 of the input programs. Each module consists of functions, global variables,
479 and symbol table entries. Modules may be combined together with the LLVM
480 linker, which merges function (and global variable) definitions, resolves
481 forward declarations, and merges symbol table entries. Here is an example of
482 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]483
484<div class="doc_code">
485<pre><i>; Declare the string constant as a global constant...</i>
486<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
487 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
488
489<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]490<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]491
492<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]494 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]495 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]496 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]497
498 <i>; Call puts function to write out the string to stdout...</i>
499 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]500 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]501 <a
502 href="#i_ret">ret</a> i32 0<br>}<br>
503</pre>
504</div>
505
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]506<p>This example is made up of a <a href="#globalvars">global variable</a> named
507 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
508 a <a href="#functionstructure">function definition</a> for
509 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]510
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]511<p>In general, a module is made up of a list of global values, where both
512 functions and global variables are global values. Global values are
513 represented by a pointer to a memory location (in this case, a pointer to an
514 array of char, and a pointer to a function), and have one of the
515 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]516
517</div>
518
519<!-- ======================================================================= -->
520<div class="doc_subsection">
521 <a name="linkage">Linkage Types</a>
522</div>
523
524<div class="doc_text">
525
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]526<p>All Global Variables and Functions have one of the following types of
527 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]528
529<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]531 <dd>Global values with private linkage are only directly accessible by objects
532 in the current module. In particular, linking code into a module with an
533 private global value may cause the private to be renamed as necessary to
534 avoid collisions. Because the symbol is private to the module, all
535 references can be updated. This doesn't show up in any symbol table in the
536 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]537
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]539 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]540 removed by the linker after evaluation. Note that (unlike private
541 symbols) linker_private symbols are subject to coalescing by the linker:
542 weak symbols get merged and redefinitions are rejected. However, unlike
543 normal strong symbols, they are removed by the linker from the final
544 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]545
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]547 <dd>Similar to private, but the value shows as a local symbol
548 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
549 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]550
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]552 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]553 into the object file corresponding to the LLVM module. They exist to
554 allow inlining and other optimizations to take place given knowledge of
555 the definition of the global, which is known to be somewhere outside the
556 module. Globals with <tt>available_externally</tt> linkage are allowed to
557 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
558 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]560 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]561 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]562 the same name when linkage occurs. This is typically used to implement
563 inline functions, templates, or other code which must be generated in each
564 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
565 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]566
567 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]568 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
569 <tt>linkonce</tt> linkage, except that unreferenced globals with
570 <tt>weak</tt> linkage may not be discarded. This is used for globals that
571 are declared "weak" in C source code.</dd>
572
573 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
574 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
575 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
576 global scope.
577 Symbols with "<tt>common</tt>" linkage are merged in the same way as
578 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]579 <tt>common</tt> symbols may not have an explicit section,
580 must have a zero initializer, and may not be marked '<a
581 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
582 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]584
585 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]586 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]587 pointer to array type. When two global variables with appending linkage
588 are linked together, the two global arrays are appended together. This is
589 the LLVM, typesafe, equivalent of having the system linker append together
590 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]591
592 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]593 <dd>The semantics of this linkage follow the ELF object file model: the symbol
594 is weak until linked, if not linked, the symbol becomes null instead of
595 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]596
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt>: </dt>
598 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]599 <dd>Some languages allow differing globals to be merged, such as two functions
600 with different semantics. Other languages, such as <tt>C++</tt>, ensure
601 that only equivalent globals are ever merged (the "one definition rule" -
602 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
603 and <tt>weak_odr</tt> linkage types to indicate that the global will only
604 be merged with equivalent globals. These linkage types are otherwise the
605 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]607 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]609 visible, meaning that it participates in linkage and can be used to
610 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611</dl>
612
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]613<p>The next two types of linkage are targeted for Microsoft Windows platform
614 only. They are designed to support importing (exporting) symbols from (to)
615 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]617<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]618 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]619 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]620 or variable via a global pointer to a pointer that is set up by the DLL
621 exporting the symbol. On Microsoft Windows targets, the pointer name is
622 formed by combining <code>__imp_</code> and the function or variable
623 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]624
625 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]626 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]627 pointer to a pointer in a DLL, so that it can be referenced with the
628 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
629 name is formed by combining <code>__imp_</code> and the function or
630 variable name.</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>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
634 another module defined a "<tt>.LC0</tt>" variable and was linked with this
635 one, one of the two would be renamed, preventing a collision. Since
636 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
637 declarations), they are accessible outside of the current module.</p>
638
639<p>It is illegal for a function <i>declaration</i> to have any linkage type
640 other than "externally visible", <tt>dllimport</tt>
641 or <tt>extern_weak</tt>.</p>
642
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]643<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]644 or <tt>weak_odr</tt> linkages.</p>
645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]646</div>
647
648<!-- ======================================================================= -->
649<div class="doc_subsection">
650 <a name="callingconv">Calling Conventions</a>
651</div>
652
653<div class="doc_text">
654
655<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]656 and <a href="#i_invoke">invokes</a> can all have an optional calling
657 convention specified for the call. The calling convention of any pair of
658 dynamic caller/callee must match, or the behavior of the program is
659 undefined. The following calling conventions are supported by LLVM, and more
660 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]661
662<dl>
663 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]664 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]665 specified) matches the target C calling conventions. This calling
666 convention supports varargs function calls and tolerates some mismatch in
667 the declared prototype and implemented declaration of the function (as
668 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]669
670 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]671 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]672 (e.g. by passing things in registers). This calling convention allows the
673 target to use whatever tricks it wants to produce fast code for the
674 target, without having to conform to an externally specified ABI
675 (Application Binary Interface). Implementations of this convention should
676 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
677 optimization</a> to be supported. This calling convention does not
678 support varargs and requires the prototype of all callees to exactly match
679 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]680
681 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]682 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]683 as possible under the assumption that the call is not commonly executed.
684 As such, these calls often preserve all registers so that the call does
685 not break any live ranges in the caller side. This calling convention
686 does not support varargs and requires the prototype of all callees to
687 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]688
689 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]690 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]691 target-specific calling conventions to be used. Target specific calling
692 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]693</dl>
694
695<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]696 support Pascal conventions or any other well-known target-independent
697 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]698
699</div>
700
701<!-- ======================================================================= -->
702<div class="doc_subsection">
703 <a name="visibility">Visibility Styles</a>
704</div>
705
706<div class="doc_text">
707
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]708<p>All Global Variables and Functions have one of the following visibility
709 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710
711<dl>
712 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]713 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]714 that the declaration is visible to other modules and, in shared libraries,
715 means that the declared entity may be overridden. On Darwin, default
716 visibility means that the declaration is visible to other modules. Default
717 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]718
719 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]720 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]721 object if they are in the same shared object. Usually, hidden visibility
722 indicates that the symbol will not be placed into the dynamic symbol
723 table, so no other module (executable or shared library) can reference it
724 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]725
726 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]727 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]728 the dynamic symbol table, but that references within the defining module
729 will bind to the local symbol. That is, the symbol cannot be overridden by
730 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]731</dl>
732
733</div>
734
735<!-- ======================================================================= -->
736<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]737 <a name="namedtypes">Named Types</a>
738</div>
739
740<div class="doc_text">
741
742<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]743 it easier to read the IR and make the IR more condensed (particularly when
744 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]745
746<div class="doc_code">
747<pre>
748%mytype = type { %mytype*, i32 }
749</pre>
750</div>
751
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]752<p>You may give a name to any <a href="#typesystem">type</a> except
753 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
754 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]755
756<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]757 and that you can therefore specify multiple names for the same type. This
758 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
759 uses structural typing, the name is not part of the type. When printing out
760 LLVM IR, the printer will pick <em>one name</em> to render all types of a
761 particular shape. This means that if you have code where two different
762 source types end up having the same LLVM type, that the dumper will sometimes
763 print the "wrong" or unexpected type. This is an important design point and
764 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]765
766</div>
767
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]768<!-- ======================================================================= -->
769<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]770 <a name="globalvars">Global Variables</a>
771</div>
772
773<div class="doc_text">
774
775<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]776 instead of run-time. Global variables may optionally be initialized, may
777 have an explicit section to be placed in, and may have an optional explicit
778 alignment specified. A variable may be defined as "thread_local", which
779 means that it will not be shared by threads (each thread will have a
780 separated copy of the variable). A variable may be defined as a global
781 "constant," which indicates that the contents of the variable
782 will <b>never</b> be modified (enabling better optimization, allowing the
783 global data to be placed in the read-only section of an executable, etc).
784 Note that variables that need runtime initialization cannot be marked
785 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]786
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]787<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
788 constant, even if the final definition of the global is not. This capability
789 can be used to enable slightly better optimization of the program, but
790 requires the language definition to guarantee that optimizations based on the
791 'constantness' are valid for the translation units that do not include the
792 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]793
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]794<p>As SSA values, global variables define pointer values that are in scope
795 (i.e. they dominate) all basic blocks in the program. Global variables
796 always define a pointer to their "content" type because they describe a
797 region of memory, and all memory objects in LLVM are accessed through
798 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]799
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]800<p>A global variable may be declared to reside in a target-specific numbered
801 address space. For targets that support them, address spaces may affect how
802 optimizations are performed and/or what target instructions are used to
803 access the variable. The default address space is zero. The address space
804 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]806<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]807 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]808
809<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]810 the alignment is set to zero, the alignment of the global is set by the
811 target to whatever it feels convenient. If an explicit alignment is
812 specified, the global is forced to have at least that much alignment. All
813 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]815<p>For example, the following defines a global in a numbered address space with
816 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]817
818<div class="doc_code">
819<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]820@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]821</pre>
822</div>
823
824</div>
825
826
827<!-- ======================================================================= -->
828<div class="doc_subsection">
829 <a name="functionstructure">Functions</a>
830</div>
831
832<div class="doc_text">
833
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]834<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
835 optional <a href="#linkage">linkage type</a>, an optional
836 <a href="#visibility">visibility style</a>, an optional
837 <a href="#callingconv">calling convention</a>, a return type, an optional
838 <a href="#paramattrs">parameter attribute</a> for the return type, a function
839 name, a (possibly empty) argument list (each with optional
840 <a href="#paramattrs">parameter attributes</a>), optional
841 <a href="#fnattrs">function attributes</a>, an optional section, an optional
842 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
843 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]845<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
846 optional <a href="#linkage">linkage type</a>, an optional
847 <a href="#visibility">visibility style</a>, an optional
848 <a href="#callingconv">calling convention</a>, a return type, an optional
849 <a href="#paramattrs">parameter attribute</a> for the return type, a function
850 name, a possibly empty list of arguments, an optional alignment, and an
851 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]852
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]853<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]854 (Control Flow Graph) for the function. Each basic block may optionally start
855 with a label (giving the basic block a symbol table entry), contains a list
856 of instructions, and ends with a <a href="#terminators">terminator</a>
857 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]858
859<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]860 executed on entrance to the function, and it is not allowed to have
861 predecessor basic blocks (i.e. there can not be any branches to the entry
862 block of a function). Because the block can have no predecessors, it also
863 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864
865<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]866 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]867
868<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]869 the alignment is set to zero, the alignment of the function is set by the
870 target to whatever it feels convenient. If an explicit alignment is
871 specified, the function is forced to have at least that much alignment. All
872 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]873
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]874<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]875<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]876<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]877define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]878 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
879 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
880 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
881 [<a href="#gc">gc</a>] { ... }
882</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]883</div>
884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]885</div>
886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]887<!-- ======================================================================= -->
888<div class="doc_subsection">
889 <a name="aliasstructure">Aliases</a>
890</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]893
894<p>Aliases act as "second name" for the aliasee value (which can be either
895 function, global variable, another alias or bitcast of global value). Aliases
896 may have an optional <a href="#linkage">linkage type</a>, and an
897 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]899<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900<div class="doc_code">
901<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]902@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]903</pre>
904</div>
905
906</div>
907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]908<!-- ======================================================================= -->
909<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]910
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]911<div class="doc_text">
912
913<p>The return type and each parameter of a function type may have a set of
914 <i>parameter attributes</i> associated with them. Parameter attributes are
915 used to communicate additional information about the result or parameters of
916 a function. Parameter attributes are considered to be part of the function,
917 not of the function type, so functions with different parameter attributes
918 can have the same function type.</p>
919
920<p>Parameter attributes are simple keywords that follow the type specified. If
921 multiple parameter attributes are needed, they are space separated. For
922 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]923
924<div class="doc_code">
925<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]926declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]927declare i32 @atoi(i8 zeroext)
928declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]929</pre>
930</div>
931
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]932<p>Note that any attributes for the function result (<tt>nounwind</tt>,
933 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]935<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]936
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]937<dl>
938 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]939 <dd>This indicates to the code generator that the parameter or return value
940 should be zero-extended to a 32-bit value by the caller (for a parameter)
941 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]942
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]943 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]944 <dd>This indicates to the code generator that the parameter or return value
945 should be sign-extended to a 32-bit value by the caller (for a parameter)
946 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]947
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]948 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]949 <dd>This indicates that this parameter or return value should be treated in a
950 special target-dependent fashion during while emitting code for a function
951 call or return (usually, by putting it in a register as opposed to memory,
952 though some targets use it to distinguish between two different kinds of
953 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]954
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]955 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]956 <dd>This indicates that the pointer parameter should really be passed by value
957 to the function. The attribute implies that a hidden copy of the pointee
958 is made between the caller and the callee, so the callee is unable to
959 modify the value in the callee. This attribute is only valid on LLVM
960 pointer arguments. It is generally used to pass structs and arrays by
961 value, but is also valid on pointers to scalars. The copy is considered
962 to belong to the caller not the callee (for example,
963 <tt><a href="#readonly">readonly</a></tt> functions should not write to
964 <tt>byval</tt> parameters). This is not a valid attribute for return
965 values. The byval attribute also supports specifying an alignment with
966 the align attribute. This has a target-specific effect on the code
967 generator that usually indicates a desired alignment for the synthesized
968 stack slot.</dd>
969
970 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer parameter specifies the address of a
972 structure that is the return value of the function in the source program.
973 This pointer must be guaranteed by the caller to be valid: loads and
974 stores to the structure may be assumed by the callee to not to trap. This
975 may only be applied to the first parameter. This is not a valid attribute
976 for return values. </dd>
977
978 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]979 <dd>This indicates that the pointer does not alias any global or any other
980 parameter. The caller is responsible for ensuring that this is the
981 case. On a function return value, <tt>noalias</tt> additionally indicates
982 that the pointer does not alias any other pointers visible to the
983 caller. For further details, please see the discussion of the NoAlias
984 response in
985 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
986 analysis</a>.</dd>
987
988 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]989 <dd>This indicates that the callee does not make any copies of the pointer
990 that outlive the callee itself. This is not a valid attribute for return
991 values.</dd>
992
993 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]994 <dd>This indicates that the pointer parameter can be excised using the
995 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
996 attribute for return values.</dd>
997</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]998
999</div>
1000
1001<!-- ======================================================================= -->
1002<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1003 <a name="gc">Garbage Collector Names</a>
1004</div>
1005
1006<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1007
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1008<p>Each function may specify a garbage collector name, which is simply a
1009 string:</p>
1010
1011<div class="doc_code">
1012<pre>
1013define void @f() gc "name" { ...
1014</pre>
1015</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1016
1017<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1018 collector which will cause the compiler to alter its output in order to
1019 support the named garbage collection algorithm.</p>
1020
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1021</div>
1022
1023<!-- ======================================================================= -->
1024<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1025 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1026</div>
1027
1028<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1029
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1030<p>Function attributes are set to communicate additional information about a
1031 function. Function attributes are considered to be part of the function, not
1032 of the function type, so functions with different parameter attributes can
1033 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1034
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1035<p>Function attributes are simple keywords that follow the type specified. If
1036 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1037
1038<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1039<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1040define void @f() noinline { ... }
1041define void @f() alwaysinline { ... }
1042define void @f() alwaysinline optsize { ... }
1043define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1044</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1045</div>
1046
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1047<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1048 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1049 <dd>This attribute indicates that the inliner should attempt to inline this
1050 function into callers whenever possible, ignoring any active inlining size
1051 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1052
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1053 <dt><tt>inlinehint</tt></dt>
1054 <dd>This attribute indicates that the source code contained a hint that inlining
1055 this function is desirable (such as the "inline" keyword in C/C++). It
1056 is just a hint; it imposes no requirements on the inliner.</dd>
1057
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1058 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1059 <dd>This attribute indicates that the inliner should never inline this
1060 function in any situation. This attribute may not be used together with
1061 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1062
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1063 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This attribute suggests that optimization passes and code generator passes
1065 make choices that keep the code size of this function low, and otherwise
1066 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1069 <dd>This function attribute indicates that the function never returns
1070 normally. This produces undefined behavior at runtime if the function
1071 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1072
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1073 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1074 <dd>This function attribute indicates that the function never returns with an
1075 unwind or exceptional control flow. If the function does unwind, its
1076 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1077
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1078 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1079 <dd>This attribute indicates that the function computes its result (or decides
1080 to unwind an exception) based strictly on its arguments, without
1081 dereferencing any pointer arguments or otherwise accessing any mutable
1082 state (e.g. memory, control registers, etc) visible to caller functions.
1083 It does not write through any pointer arguments
1084 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1085 changes any state visible to callers. This means that it cannot unwind
1086 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1087 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1088
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1089 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This attribute indicates that the function does not write through any
1091 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1092 arguments) or otherwise modify any state (e.g. memory, control registers,
1093 etc) visible to caller functions. It may dereference pointer arguments
1094 and read state that may be set in the caller. A readonly function always
1095 returns the same value (or unwinds an exception identically) when called
1096 with the same set of arguments and global state. It cannot unwind an
1097 exception by calling the <tt>C++</tt> exception throwing methods, but may
1098 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1099
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1100 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1101 <dd>This attribute indicates that the function should emit a stack smashing
1102 protector. It is in the form of a "canary"&mdash;a random value placed on
1103 the stack before the local variables that's checked upon return from the
1104 function to see if it has been overwritten. A heuristic is used to
1105 determine if a function needs stack protectors or not.<br>
1106<br>
1107 If a function that has an <tt>ssp</tt> attribute is inlined into a
1108 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1109 function will have an <tt>ssp</tt> attribute.</dd>
1110
1111 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This attribute indicates that the function should <em>always</em> emit a
1113 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1114 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1115<br>
1116 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1117 function that doesn't have an <tt>sspreq</tt> attribute or which has
1118 an <tt>ssp</tt> attribute, then the resulting function will have
1119 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1120
1121 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1122 <dd>This attribute indicates that the code generator should not use a red
1123 zone, even if the target-specific ABI normally permits it.</dd>
1124
1125 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attributes disables implicit floating point instructions.</dd>
1127
1128 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1129 <dd>This attribute disables prologue / epilogue emission for the function.
1130 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1131</dl>
1132
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1133</div>
1134
1135<!-- ======================================================================= -->
1136<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1137 <a name="moduleasm">Module-Level Inline Assembly</a>
1138</div>
1139
1140<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1141
1142<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1143 the GCC "file scope inline asm" blocks. These blocks are internally
1144 concatenated by LLVM and treated as a single unit, but may be separated in
1145 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1146
1147<div class="doc_code">
1148<pre>
1149module asm "inline asm code goes here"
1150module asm "more can go here"
1151</pre>
1152</div>
1153
1154<p>The strings can contain any character by escaping non-printable characters.
1155 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]1156 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1157
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1158<p>The inline asm code is simply printed to the machine code .s file when
1159 assembly code is generated.</p>
1160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1161</div>
1162
1163<!-- ======================================================================= -->
1164<div class="doc_subsection">
1165 <a name="datalayout">Data Layout</a>
1166</div>
1167
1168<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1170<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1171 data is to be laid out in memory. The syntax for the data layout is
1172 simply:</p>
1173
1174<div class="doc_code">
1175<pre>
1176target datalayout = "<i>layout specification</i>"
1177</pre>
1178</div>
1179
1180<p>The <i>layout specification</i> consists of a list of specifications
1181 separated by the minus sign character ('-'). Each specification starts with
1182 a letter and may include other information after the letter to define some
1183 aspect of the data layout. The specifications accepted are as follows:</p>
1184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1185<dl>
1186 <dt><tt>E</tt></dt>
1187 <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]1188 bits with the most significance have the lowest address location.</dd>
1189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1190 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1191 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1192 the bits with the least significance have the lowest address
1193 location.</dd>
1194
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1195 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1196 <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]1197 <i>preferred</i> alignments. All sizes are in bits. Specifying
1198 the <i>pref</i> alignment is optional. If omitted, the
1199 preceding <tt>:</tt> should be omitted too.</dd>
1200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1201 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1203 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1204
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1205 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1206 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1207 <i>size</i>.</dd>
1208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1209 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1210 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1211 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1212 (double).</dd>
1213
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1214 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1215 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1216 <i>size</i>.</dd>
1217
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1218 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1219 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1220 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1221</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1223<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1224 default set of specifications which are then (possibly) overriden by the
1225 specifications in the <tt>datalayout</tt> keyword. The default specifications
1226 are given in this list:</p>
1227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228<ul>
1229 <li><tt>E</tt> - big endian</li>
1230 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1231 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1232 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1233 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1234 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1235 <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]1236 alignment of 64-bits</li>
1237 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1238 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1239 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1240 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1241 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1242 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1243</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1244
1245<p>When LLVM is determining the alignment for a given type, it uses the
1246 following rules:</p>
1247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1248<ol>
1249 <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]1250 specification is used.</li>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252 <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]1253 smallest integer type that is larger than the bitwidth of the sought type
1254 is used. If none of the specifications are larger than the bitwidth then
1255 the the largest integer type is used. For example, given the default
1256 specifications above, the i7 type will use the alignment of i8 (next
1257 largest) while both i65 and i256 will use the alignment of i64 (largest
1258 specified).</li>
1259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1260 <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]1261 largest vector type that is smaller than the sought vector type will be
1262 used as a fall back. This happens because &lt;128 x double&gt; can be
1263 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1266</div>
1267
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1268<!-- ======================================================================= -->
1269<div class="doc_subsection">
1270 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1271</div>
1272
1273<div class="doc_text">
1274
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1275<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1276with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1277is undefined. Pointer values are associated with address ranges
1278according to the following rules:</p>
1279
1280<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1281 <li>A pointer value formed from a
1282 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1283 is associated with the addresses associated with the first operand
1284 of the <tt>getelementptr</tt>.</li>
1285 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1286 range of the variable's storage.</li>
1287 <li>The result value of an allocation instruction is associated with
1288 the address range of the allocated storage.</li>
1289 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1290 no address.</li>
1291 <li>A pointer value formed by an
1292 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1293 address ranges of all pointer values that contribute (directly or
1294 indirectly) to the computation of the pointer's value.</li>
1295 <li>The result value of a
1296 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1297 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1298 <li>An integer constant other than zero or a pointer value returned
1299 from a function not defined within LLVM may be associated with address
1300 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1301 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1302 allocated by mechanisms provided by LLVM.</li>
1303 </ul>
1304
1305<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1306<tt><a href="#i_load">load</a></tt> merely indicates the size and
1307alignment of the memory from which to load, as well as the
1308interpretation of the value. The first operand of a
1309<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1310and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1311
1312<p>Consequently, type-based alias analysis, aka TBAA, aka
1313<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1314LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1315additional information which specialized optimization passes may use
1316to implement type-based alias analysis.</p>
1317
1318</div>
1319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1320<!-- *********************************************************************** -->
1321<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1322<!-- *********************************************************************** -->
1323
1324<div class="doc_text">
1325
1326<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1327 intermediate representation. Being typed enables a number of optimizations
1328 to be performed on the intermediate representation directly, without having
1329 to do extra analyses on the side before the transformation. A strong type
1330 system makes it easier to read the generated code and enables novel analyses
1331 and transformations that are not feasible to perform on normal three address
1332 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1333
1334</div>
1335
1336<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1337<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1338Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1339
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1340<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1341
1342<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1343
1344<table border="1" cellspacing="0" cellpadding="4">
1345 <tbody>
1346 <tr><th>Classification</th><th>Types</th></tr>
1347 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1348 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1349 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1350 </tr>
1351 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_floating">floating point</a></td>
1353 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1354 </tr>
1355 <tr>
1356 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1357 <td><a href="#t_integer">integer</a>,
1358 <a href="#t_floating">floating point</a>,
1359 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1360 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1361 <a href="#t_struct">structure</a>,
1362 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_label">label</a>,
1364 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1365 </td>
1366 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1367 <tr>
1368 <td><a href="#t_primitive">primitive</a></td>
1369 <td><a href="#t_label">label</a>,
1370 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1371 <a href="#t_floating">floating point</a>,
1372 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1373 </tr>
1374 <tr>
1375 <td><a href="#t_derived">derived</a></td>
1376 <td><a href="#t_integer">integer</a>,
1377 <a href="#t_array">array</a>,
1378 <a href="#t_function">function</a>,
1379 <a href="#t_pointer">pointer</a>,
1380 <a href="#t_struct">structure</a>,
1381 <a href="#t_pstruct">packed structure</a>,
1382 <a href="#t_vector">vector</a>,
1383 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1384 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1385 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1386 </tbody>
1387</table>
1388
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1389<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1390 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1391 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1393</div>
1394
1395<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1396<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1397
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1398<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1399
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1400<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1401 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1402
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1403</div>
1404
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1405<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1406<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1407
1408<div class="doc_text">
1409
1410<h5>Overview:</h5>
1411<p>The integer type is a very simple type that simply specifies an arbitrary
1412 bit width for the integer type desired. Any bit width from 1 bit to
1413 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1414
1415<h5>Syntax:</h5>
1416<pre>
1417 iN
1418</pre>
1419
1420<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1421 value.</p>
1422
1423<h5>Examples:</h5>
1424<table class="layout">
1425 <tr class="layout">
1426 <td class="left"><tt>i1</tt></td>
1427 <td class="left">a single-bit integer.</td>
1428 </tr>
1429 <tr class="layout">
1430 <td class="left"><tt>i32</tt></td>
1431 <td class="left">a 32-bit integer.</td>
1432 </tr>
1433 <tr class="layout">
1434 <td class="left"><tt>i1942652</tt></td>
1435 <td class="left">a really big integer of over 1 million bits.</td>
1436 </tr>
1437</table>
1438
1439<p>Note that the code generator does not yet support large integer types to be
1440 used as function return types. The specific limit on how large a return type
1441 the code generator can currently handle is target-dependent; currently it's
1442 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
1443
1444</div>
1445
1446<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1447<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1448
1449<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1450
1451<table>
1452 <tbody>
1453 <tr><th>Type</th><th>Description</th></tr>
1454 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1455 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1456 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1457 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1458 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1459 </tbody>
1460</table>
1461
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1462</div>
1463
1464<!-- _______________________________________________________________________ -->
1465<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1466
1467<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1468
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1469<h5>Overview:</h5>
1470<p>The void type does not represent any value and has no size.</p>
1471
1472<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1473<pre>
1474 void
1475</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1476
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1477</div>
1478
1479<!-- _______________________________________________________________________ -->
1480<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1481
1482<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1483
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1484<h5>Overview:</h5>
1485<p>The label type represents code labels.</p>
1486
1487<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1488<pre>
1489 label
1490</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1491
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1492</div>
1493
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1494<!-- _______________________________________________________________________ -->
1495<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1496
1497<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1498
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1499<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1500<p>The metadata type represents embedded metadata. No derived types may be
1501 created from metadata except for <a href="#t_function">function</a>
1502 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1503
1504<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1505<pre>
1506 metadata
1507</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1508
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1509</div>
1510
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1511
1512<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1513<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1514
1515<div class="doc_text">
1516
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1517<p>The real power in LLVM comes from the derived types in the system. This is
1518 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1519 useful types. Each of these types contain one or more element types which
1520 may be a primitive type, or another derived type. For example, it is
1521 possible to have a two dimensional array, using an array as the element type
1522 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1524</div>
1525
1526<!-- _______________________________________________________________________ -->
1527<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1528
1529<div class="doc_text">
1530
1531<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1532<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1533 sequentially in memory. The array type requires a size (number of elements)
1534 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1535
1536<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1537<pre>
1538 [&lt;# elements&gt; x &lt;elementtype&gt;]
1539</pre>
1540
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1541<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1542 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1543
1544<h5>Examples:</h5>
1545<table class="layout">
1546 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1547 <td class="left"><tt>[40 x i32]</tt></td>
1548 <td class="left">Array of 40 32-bit integer values.</td>
1549 </tr>
1550 <tr class="layout">
1551 <td class="left"><tt>[41 x i32]</tt></td>
1552 <td class="left">Array of 41 32-bit integer values.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>[4 x i8]</tt></td>
1556 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1557 </tr>
1558</table>
1559<p>Here are some examples of multidimensional arrays:</p>
1560<table class="layout">
1561 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1562 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1563 <td class="left">3x4 array of 32-bit integer values.</td>
1564 </tr>
1565 <tr class="layout">
1566 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1567 <td class="left">12x10 array of single precision floating point values.</td>
1568 </tr>
1569 <tr class="layout">
1570 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1571 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1572 </tr>
1573</table>
1574
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1575<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1576 length array. Normally, accesses past the end of an array are undefined in
1577 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1578 a special case, however, zero length arrays are recognized to be variable
1579 length. This allows implementation of 'pascal style arrays' with the LLVM
1580 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1581
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1582<p>Note that the code generator does not yet support large aggregate types to be
1583 used as function return types. The specific limit on how large an aggregate
1584 return type the code generator can currently handle is target-dependent, and
1585 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1587</div>
1588
1589<!-- _______________________________________________________________________ -->
1590<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1592<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1594<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1595<p>The function type can be thought of as a function signature. It consists of
1596 a return type and a list of formal parameter types. The return type of a
1597 function type is a scalar type, a void type, or a struct type. If the return
1598 type is a struct type then all struct elements must be of first class types,
1599 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1601<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1602<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1603 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1604</pre>
1605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1606<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]1607 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1608 which indicates that the function takes a variable number of arguments.
1609 Variable argument functions can access their arguments with
1610 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1611 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1612 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1614<h5>Examples:</h5>
1615<table class="layout">
1616 <tr class="layout">
1617 <td class="left"><tt>i32 (i32)</tt></td>
1618 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1619 </td>
1620 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1621 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1622 </tt></td>
1623 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1624 an <tt>i16</tt> that should be sign extended and a
1625 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1626 <tt>float</tt>.
1627 </td>
1628 </tr><tr class="layout">
1629 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1630 <td class="left">A vararg function that takes at least one
1631 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1632 which returns an integer. This is the signature for <tt>printf</tt> in
1633 LLVM.
1634 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1635 </tr><tr class="layout">
1636 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1637 <td class="left">A function taking an <tt>i32</tt>, returning a
1638 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1639 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1640 </tr>
1641</table>
1642
1643</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1645<!-- _______________________________________________________________________ -->
1646<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1648<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1651<p>The structure type is used to represent a collection of data members together
1652 in memory. The packing of the field types is defined to match the ABI of the
1653 underlying processor. The elements of a structure may be any type that has a
1654 size.</p>
1655
1656<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1657 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1658 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1660<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1661<pre>
1662 { &lt;type list&gt; }
1663</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1665<h5>Examples:</h5>
1666<table class="layout">
1667 <tr class="layout">
1668 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1669 <td class="left">A triple of three <tt>i32</tt> values</td>
1670 </tr><tr class="layout">
1671 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1672 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1673 second element is a <a href="#t_pointer">pointer</a> to a
1674 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1675 an <tt>i32</tt>.</td>
1676 </tr>
1677</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1678
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1679<p>Note that the code generator does not yet support large aggregate types to be
1680 used as function return types. The specific limit on how large an aggregate
1681 return type the code generator can currently handle is target-dependent, and
1682 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1684</div>
1685
1686<!-- _______________________________________________________________________ -->
1687<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1688</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1690<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1692<h5>Overview:</h5>
1693<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1694 together in memory. There is no padding between fields. Further, the
1695 alignment of a packed structure is 1 byte. The elements of a packed
1696 structure may be any type that has a size.</p>
1697
1698<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1699 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1700 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1702<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1703<pre>
1704 &lt; { &lt;type list&gt; } &gt;
1705</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1707<h5>Examples:</h5>
1708<table class="layout">
1709 <tr class="layout">
1710 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1711 <td class="left">A triple of three <tt>i32</tt> values</td>
1712 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1713 <td class="left">
1714<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1715 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1716 second element is a <a href="#t_pointer">pointer</a> to a
1717 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1718 an <tt>i32</tt>.</td>
1719 </tr>
1720</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1722</div>
1723
1724<!-- _______________________________________________________________________ -->
1725<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1726
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1727<div class="doc_text">
1728
1729<h5>Overview:</h5>
1730<p>As in many languages, the pointer type represents a pointer or reference to
1731 another object, which must live in memory. Pointer types may have an optional
1732 address space attribute defining the target-specific numbered address space
1733 where the pointed-to object resides. The default address space is zero.</p>
1734
1735<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1736 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1738<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1739<pre>
1740 &lt;type&gt; *
1741</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743<h5>Examples:</h5>
1744<table class="layout">
1745 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1746 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1747 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1748 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1749 </tr>
1750 <tr class="layout">
1751 <td class="left"><tt>i32 (i32 *) *</tt></td>
1752 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1753 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1754 <tt>i32</tt>.</td>
1755 </tr>
1756 <tr class="layout">
1757 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1758 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1759 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1760 </tr>
1761</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1763</div>
1764
1765<!-- _______________________________________________________________________ -->
1766<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768<div class="doc_text">
1769
1770<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1771<p>A vector type is a simple derived type that represents a vector of elements.
1772 Vector types are used when multiple primitive data are operated in parallel
1773 using a single instruction (SIMD). A vector type requires a size (number of
1774 elements) and an underlying primitive data type. Vectors must have a power
1775 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1776 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777
1778<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1779<pre>
1780 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1781</pre>
1782
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1783<p>The number of elements is a constant integer value; elementtype may be any
1784 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1785
1786<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1787<table class="layout">
1788 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1789 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1790 <td class="left">Vector of 4 32-bit integer values.</td>
1791 </tr>
1792 <tr class="layout">
1793 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1794 <td class="left">Vector of 8 32-bit floating-point values.</td>
1795 </tr>
1796 <tr class="layout">
1797 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1798 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1799 </tr>
1800</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1801
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1802<p>Note that the code generator does not yet support large vector types to be
1803 used as function return types. The specific limit on how large a vector
1804 return type codegen can currently handle is target-dependent; currently it's
1805 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1807</div>
1808
1809<!-- _______________________________________________________________________ -->
1810<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1811<div class="doc_text">
1812
1813<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1814<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1815 corresponds (for example) to the C notion of a forward declared structure
1816 type. In LLVM, opaque types can eventually be resolved to any type (not just
1817 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1818
1819<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1820<pre>
1821 opaque
1822</pre>
1823
1824<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825<table class="layout">
1826 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1827 <td class="left"><tt>opaque</tt></td>
1828 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1829 </tr>
1830</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1831
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1832</div>
1833
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1834<!-- ======================================================================= -->
1835<div class="doc_subsection">
1836 <a name="t_uprefs">Type Up-references</a>
1837</div>
1838
1839<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1840
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1841<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1842<p>An "up reference" allows you to refer to a lexically enclosing type without
1843 requiring it to have a name. For instance, a structure declaration may
1844 contain a pointer to any of the types it is lexically a member of. Example
1845 of up references (with their equivalent as named type declarations)
1846 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1847
1848<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1849 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1850 { \2 }* %y = type { %y }*
1851 \1* %z = type %z*
1852</pre>
1853
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1854<p>An up reference is needed by the asmprinter for printing out cyclic types
1855 when there is no declared name for a type in the cycle. Because the
1856 asmprinter does not want to print out an infinite type string, it needs a
1857 syntax to handle recursive types that have no names (all names are optional
1858 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1859
1860<h5>Syntax:</h5>
1861<pre>
1862 \&lt;level&gt;
1863</pre>
1864
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1865<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]1866
1867<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1868<table class="layout">
1869 <tr class="layout">
1870 <td class="left"><tt>\1*</tt></td>
1871 <td class="left">Self-referential pointer.</td>
1872 </tr>
1873 <tr class="layout">
1874 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1875 <td class="left">Recursive structure where the upref refers to the out-most
1876 structure.</td>
1877 </tr>
1878</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1879
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1880</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1881
1882<!-- *********************************************************************** -->
1883<div class="doc_section"> <a name="constants">Constants</a> </div>
1884<!-- *********************************************************************** -->
1885
1886<div class="doc_text">
1887
1888<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1889 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1890
1891</div>
1892
1893<!-- ======================================================================= -->
1894<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1895
1896<div class="doc_text">
1897
1898<dl>
1899 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1900 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1901 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1902
1903 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1904 <dd>Standard integers (such as '4') are constants of
1905 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1906 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907
1908 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1909 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1910 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1911 notation (see below). The assembler requires the exact decimal value of a
1912 floating-point constant. For example, the assembler accepts 1.25 but
1913 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1914 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1915
1916 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1917 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1918 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1919</dl>
1920
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1921<p>The one non-intuitive notation for constants is the hexadecimal form of
1922 floating point constants. For example, the form '<tt>double
1923 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1924 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1925 constants are required (and the only time that they are generated by the
1926 disassembler) is when a floating point constant must be emitted but it cannot
1927 be represented as a decimal floating point number in a reasonable number of
1928 digits. For example, NaN's, infinities, and other special values are
1929 represented in their IEEE hexadecimal format so that assembly and disassembly
1930 do not cause any bits to change in the constants.</p>
1931
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1932<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1933 represented using the 16-digit form shown above (which matches the IEEE754
1934 representation for double); float values must, however, be exactly
1935 representable as IEE754 single precision. Hexadecimal format is always used
1936 for long double, and there are three forms of long double. The 80-bit format
1937 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1938 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1939 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1940 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1941 currently supported target uses this format. Long doubles will only work if
1942 they match the long double format on your target. All hexadecimal formats
1943 are big-endian (sign bit at the left).</p>
1944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1945</div>
1946
1947<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1948<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1949<a name="aggregateconstants"></a> <!-- old anchor -->
1950<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1951</div>
1952
1953<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1954
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1955<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1956 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1957
1958<dl>
1959 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1960 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1961 type definitions (a comma separated list of elements, surrounded by braces
1962 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1963 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1964 Structure constants must have <a href="#t_struct">structure type</a>, and
1965 the number and types of elements must match those specified by the
1966 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967
1968 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1969 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1970 definitions (a comma separated list of elements, surrounded by square
1971 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1972 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1973 the number and types of elements must match those specified by the
1974 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1975
1976 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1977 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1978 definitions (a comma separated list of elements, surrounded by
1979 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1980 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1981 have <a href="#t_vector">vector type</a>, and the number and types of
1982 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983
1984 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1985 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1986 value to zero of <em>any</em> type, including scalar and aggregate types.
1987 This is often used to avoid having to print large zero initializers
1988 (e.g. for large arrays) and is always exactly equivalent to using explicit
1989 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1990
1991 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1992 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1993 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1994 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1995 be interpreted as part of the instruction stream, metadata is a place to
1996 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1997</dl>
1998
1999</div>
2000
2001<!-- ======================================================================= -->
2002<div class="doc_subsection">
2003 <a name="globalconstants">Global Variable and Function Addresses</a>
2004</div>
2005
2006<div class="doc_text">
2007
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2008<p>The addresses of <a href="#globalvars">global variables</a>
2009 and <a href="#functionstructure">functions</a> are always implicitly valid
2010 (link-time) constants. These constants are explicitly referenced when
2011 the <a href="#identifiers">identifier for the global</a> is used and always
2012 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2013 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2014
2015<div class="doc_code">
2016<pre>
2017@X = global i32 17
2018@Y = global i32 42
2019@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2020</pre>
2021</div>
2022
2023</div>
2024
2025<!-- ======================================================================= -->
2026<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2027<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2028
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2029<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]2030 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2031 Undefined values may be of any type (other than label or void) and be used
2032 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2033
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2034<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2035 program is well defined no matter what value is used. This gives the
2036 compiler more freedom to optimize. Here are some examples of (potentially
2037 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2038
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2039
2040<div class="doc_code">
2041<pre>
2042 %A = add %X, undef
2043 %B = sub %X, undef
2044 %C = xor %X, undef
2045Safe:
2046 %A = undef
2047 %B = undef
2048 %C = undef
2049</pre>
2050</div>
2051
2052<p>This is safe because all of the output bits are affected by the undef bits.
2053Any output bit can have a zero or one depending on the input bits.</p>
2054
2055<div class="doc_code">
2056<pre>
2057 %A = or %X, undef
2058 %B = and %X, undef
2059Safe:
2060 %A = -1
2061 %B = 0
2062Unsafe:
2063 %A = undef
2064 %B = undef
2065</pre>
2066</div>
2067
2068<p>These logical operations have bits that are not always affected by the input.
2069For example, if "%X" has a zero bit, then the output of the 'and' operation will
2070always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2071such, it is unsafe to optimize or assume that the result of the and is undef.
2072However, it is safe to assume that all bits of the undef could be 0, and
2073optimize the and to 0. Likewise, it is safe to assume that all the bits of
2074the undef operand to the or could be set, allowing the or to be folded to
2075-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2076
2077<div class="doc_code">
2078<pre>
2079 %A = select undef, %X, %Y
2080 %B = select undef, 42, %Y
2081 %C = select %X, %Y, undef
2082Safe:
2083 %A = %X (or %Y)
2084 %B = 42 (or %Y)
2085 %C = %Y
2086Unsafe:
2087 %A = undef
2088 %B = undef
2089 %C = undef
2090</pre>
2091</div>
2092
2093<p>This set of examples show that undefined select (and conditional branch)
2094conditions can go "either way" but they have to come from one of the two
2095operands. In the %A example, if %X and %Y were both known to have a clear low
2096bit, then %A would have to have a cleared low bit. However, in the %C example,
2097the optimizer is allowed to assume that the undef operand could be the same as
2098%Y, allowing the whole select to be eliminated.</p>
2099
2100
2101<div class="doc_code">
2102<pre>
2103 %A = xor undef, undef
2104
2105 %B = undef
2106 %C = xor %B, %B
2107
2108 %D = undef
2109 %E = icmp lt %D, 4
2110 %F = icmp gte %D, 4
2111
2112Safe:
2113 %A = undef
2114 %B = undef
2115 %C = undef
2116 %D = undef
2117 %E = undef
2118 %F = undef
2119</pre>
2120</div>
2121
2122<p>This example points out that two undef operands are not necessarily the same.
2123This can be surprising to people (and also matches C semantics) where they
2124assume that "X^X" is always zero, even if X is undef. This isn't true for a
2125number of reasons, but the short answer is that an undef "variable" can
2126arbitrarily change its value over its "live range". This is true because the
2127"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2128logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2129so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2130to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2131would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2132
2133<div class="doc_code">
2134<pre>
2135 %A = fdiv undef, %X
2136 %B = fdiv %X, undef
2137Safe:
2138 %A = undef
2139b: unreachable
2140</pre>
2141</div>
2142
2143<p>These examples show the crucial difference between an <em>undefined
2144value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2145allowed to have an arbitrary bit-pattern. This means that the %A operation
2146can be constant folded to undef because the undef could be an SNaN, and fdiv is
2147not (currently) defined on SNaN's. However, in the second example, we can make
2148a more aggressive assumption: because the undef is allowed to be an arbitrary
2149value, 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]2150has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2151does not execute at all. This allows us to delete the divide and all code after
2152it: since the undefined operation "can't happen", the optimizer can assume that
2153it occurs in dead code.
2154</p>
2155
2156<div class="doc_code">
2157<pre>
2158a: store undef -> %X
2159b: store %X -> undef
2160Safe:
2161a: &lt;deleted&gt;
2162b: unreachable
2163</pre>
2164</div>
2165
2166<p>These examples reiterate the fdiv example: a store "of" an undefined value
2167can be assumed to not have any effect: we can assume that the value is
2168overwritten with bits that happen to match what was already there. However, a
2169store "to" an undefined location could clobber arbitrary memory, therefore, it
2170has undefined behavior.</p>
2171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2172</div>
2173
2174<!-- ======================================================================= -->
2175<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2176</div>
2177
2178<div class="doc_text">
2179
2180<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2181 to be used as constants. Constant expressions may be of
2182 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2183 operation that does not have side effects (e.g. load and call are not
2184 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2185
2186<dl>
2187 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2188 <dd>Truncate a constant to another type. The bit size of CST must be larger
2189 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2190
2191 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2192 <dd>Zero extend a constant to another type. The bit size of CST must be
2193 smaller or equal to the bit size of TYPE. Both types must be
2194 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2195
2196 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2197 <dd>Sign extend a constant to another type. The bit size of CST must be
2198 smaller or equal to the bit size of TYPE. Both types must be
2199 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2200
2201 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2202 <dd>Truncate a floating point constant to another floating point type. The
2203 size of CST must be larger than the size of TYPE. Both types must be
2204 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2205
2206 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2207 <dd>Floating point extend a constant to another type. The size of CST must be
2208 smaller or equal to the size of TYPE. Both types must be floating
2209 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2210
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2211 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2212 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2213 constant. TYPE must be a scalar or vector integer type. CST must be of
2214 scalar or vector floating point type. Both CST and TYPE must be scalars,
2215 or vectors of the same number of elements. If the value won't fit in the
2216 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2217
2218 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2219 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2220 constant. TYPE must be a scalar or vector integer type. CST must be of
2221 scalar or vector floating point type. Both CST and TYPE must be scalars,
2222 or vectors of the same number of elements. If the value won't fit in the
2223 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2224
2225 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2226 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2227 constant. TYPE must be a scalar or vector floating point type. CST must be
2228 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2229 vectors of the same number of elements. If the value won't fit in the
2230 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2231
2232 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2233 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2234 constant. TYPE must be a scalar or vector floating point type. CST must be
2235 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2236 vectors of the same number of elements. If the value won't fit in the
2237 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2238
2239 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2240 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2241 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2242 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2243 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244
2245 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2246 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2247 type. CST must be of integer type. The CST value is zero extended,
2248 truncated, or unchanged to make it fit in a pointer size. This one is
2249 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2250
2251 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2252 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2253 are the same as those for the <a href="#i_bitcast">bitcast
2254 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2255
2256 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2257 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2258 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2259 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2260 instruction, the index list may have zero or more indexes, which are
2261 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2262
2263 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2264 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2265
2266 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2267 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2268
2269 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2270 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2271
2272 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2273 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2274 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2275
2276 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2277 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2278 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279
2280 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2281 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2282 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2283
2284 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2285 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2286 be any of the <a href="#binaryops">binary</a>
2287 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2288 on operands are the same as those for the corresponding instruction
2289 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2290</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2292</div>
2293
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2294<!-- ======================================================================= -->
2295<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2296</div>
2297
2298<div class="doc_text">
2299
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2300<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2301 stream without affecting the behaviour of the program. There are two
2302 metadata primitives, strings and nodes. All metadata has the
2303 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2304 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2305
2306<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2307 any character by escaping non-printable characters with "\xx" where "xx" is
2308 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2309
2310<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2311 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2312 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2313 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2314
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2315<p>A metadata node will attempt to track changes to the values it holds. In the
2316 event that a value is deleted, it will be replaced with a typeless
2317 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2318
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2319<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2320 the program that isn't available in the instructions, or that isn't easily
2321 computable. Similarly, the code generator may expect a certain metadata
2322 format to be used to express debugging information.</p>
2323
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2324</div>
2325
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2326<!-- *********************************************************************** -->
2327<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2328<!-- *********************************************************************** -->
2329
2330<!-- ======================================================================= -->
2331<div class="doc_subsection">
2332<a name="inlineasm">Inline Assembler Expressions</a>
2333</div>
2334
2335<div class="doc_text">
2336
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2337<p>LLVM supports inline assembler expressions (as opposed
2338 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2339 a special value. This value represents the inline assembler as a string
2340 (containing the instructions to emit), a list of operand constraints (stored
2341 as a string), and a flag that indicates whether or not the inline asm
2342 expression has side effects. An example inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2343
2344<div class="doc_code">
2345<pre>
2346i32 (i32) asm "bswap $0", "=r,r"
2347</pre>
2348</div>
2349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2350<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2351 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2352 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353
2354<div class="doc_code">
2355<pre>
2356%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2357</pre>
2358</div>
2359
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2360<p>Inline asms with side effects not visible in the constraint list must be
2361 marked as having side effects. This is done through the use of the
2362 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363
2364<div class="doc_code">
2365<pre>
2366call void asm sideeffect "eieio", ""()
2367</pre>
2368</div>
2369
2370<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2371 documented here. Constraints on what can be done (e.g. duplication, moving,
2372 etc need to be documented). This is probably best done by reference to
2373 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2374
2375</div>
2376
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2377
2378<!-- *********************************************************************** -->
2379<div class="doc_section">
2380 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2381</div>
2382<!-- *********************************************************************** -->
2383
2384<p>LLVM has a number of "magic" global variables that contain data that affect
2385code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2386of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2387section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2388by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2389
2390<!-- ======================================================================= -->
2391<div class="doc_subsection">
2392<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2393</div>
2394
2395<div class="doc_text">
2396
2397<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2398href="#linkage_appending">appending linkage</a>. This array contains a list of
2399pointers to global variables and functions which may optionally have a pointer
2400cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2401
2402<pre>
2403 @X = global i8 4
2404 @Y = global i32 123
2405
2406 @llvm.used = appending global [2 x i8*] [
2407 i8* @X,
2408 i8* bitcast (i32* @Y to i8*)
2409 ], section "llvm.metadata"
2410</pre>
2411
2412<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2413compiler, assembler, and linker are required to treat the symbol as if there is
2414a reference to the global that it cannot see. For example, if a variable has
2415internal linkage and no references other than that from the <tt>@llvm.used</tt>
2416list, it cannot be deleted. This is commonly used to represent references from
2417inline asms and other things the compiler cannot "see", and corresponds to
2418"attribute((used))" in GNU C.</p>
2419
2420<p>On some targets, the code generator must emit a directive to the assembler or
2421object file to prevent the assembler and linker from molesting the symbol.</p>
2422
2423</div>
2424
2425<!-- ======================================================================= -->
2426<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2427<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2428</div>
2429
2430<div class="doc_text">
2431
2432<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2433<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2434touching the symbol. On targets that support it, this allows an intelligent
2435linker to optimize references to the symbol without being impeded as it would be
2436by <tt>@llvm.used</tt>.</p>
2437
2438<p>This is a rare construct that should only be used in rare circumstances, and
2439should not be exposed to source languages.</p>
2440
2441</div>
2442
2443<!-- ======================================================================= -->
2444<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2445<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2446</div>
2447
2448<div class="doc_text">
2449
2450<p>TODO: Describe this.</p>
2451
2452</div>
2453
2454<!-- ======================================================================= -->
2455<div class="doc_subsection">
2456<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2457</div>
2458
2459<div class="doc_text">
2460
2461<p>TODO: Describe this.</p>
2462
2463</div>
2464
2465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2466<!-- *********************************************************************** -->
2467<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2468<!-- *********************************************************************** -->
2469
2470<div class="doc_text">
2471
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2472<p>The LLVM instruction set consists of several different classifications of
2473 instructions: <a href="#terminators">terminator
2474 instructions</a>, <a href="#binaryops">binary instructions</a>,
2475 <a href="#bitwiseops">bitwise binary instructions</a>,
2476 <a href="#memoryops">memory instructions</a>, and
2477 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478
2479</div>
2480
2481<!-- ======================================================================= -->
2482<div class="doc_subsection"> <a name="terminators">Terminator
2483Instructions</a> </div>
2484
2485<div class="doc_text">
2486
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2487<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2488 in a program ends with a "Terminator" instruction, which indicates which
2489 block should be executed after the current block is finished. These
2490 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2491 control flow, not values (the one exception being the
2492 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2493
2494<p>There are six different terminator instructions: the
2495 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2496 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2497 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2498 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2499 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2500 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501
2502</div>
2503
2504<!-- _______________________________________________________________________ -->
2505<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2506Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2510<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2511<pre>
2512 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]2513 ret void <i>; Return from void function</i>
2514</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2516<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2517<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2518 a value) from a function back to the caller.</p>
2519
2520<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2521 value and then causes control flow, and one that just causes control flow to
2522 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2524<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2525<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2526 return value. The type of the return value must be a
2527 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2528
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2529<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2530 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2531 value or a return value with a type that does not match its type, or if it
2532 has a void return type and contains a '<tt>ret</tt>' instruction with a
2533 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2536<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2537 the calling function's context. If the caller is a
2538 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2539 instruction after the call. If the caller was an
2540 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2541 the beginning of the "normal" destination block. If the instruction returns
2542 a value, that value shall set the call or invoke instruction's return
2543 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2546<pre>
2547 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2549 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]2550</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2551
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2552<p>Note that the code generator does not yet fully support large
2553 return values. The specific sizes that are currently supported are
2554 dependent on the target. For integers, on 32-bit targets the limit
2555 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2556 For aggregate types, the current limits are dependent on the element
2557 types; for example targets are often limited to 2 total integer
2558 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560</div>
2561<!-- _______________________________________________________________________ -->
2562<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2564<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2565
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2566<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2567<pre>
2568 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]2569</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2571<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2572<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2573 different basic block in the current function. There are two forms of this
2574 instruction, corresponding to a conditional branch and an unconditional
2575 branch.</p>
2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2578<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2579 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2580 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2581 target.</p>
2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Semantics:</h5>
2584<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2585 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2586 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2587 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2590<pre>
2591Test:
2592 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2593 br i1 %cond, label %IfEqual, label %IfUnequal
2594IfEqual:
2595 <a href="#i_ret">ret</a> i32 1
2596IfUnequal:
2597 <a href="#i_ret">ret</a> i32 0
2598</pre>
2599
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602<!-- _______________________________________________________________________ -->
2603<div class="doc_subsubsection">
2604 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2605</div>
2606
2607<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2609<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2610<pre>
2611 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2612</pre>
2613
2614<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615<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]2616 several different places. It is a generalization of the '<tt>br</tt>'
2617 instruction, allowing a branch to occur to one of many possible
2618 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2619
2620<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2622 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2623 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2624 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2625
2626<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2628 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2629 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2630 transferred to the corresponding destination; otherwise, control flow is
2631 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2632
2633<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2635 <tt>switch</tt> instruction, this instruction may be code generated in
2636 different ways. For example, it could be generated as a series of chained
2637 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2638
2639<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2640<pre>
2641 <i>; Emulate a conditional br instruction</i>
2642 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2643 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2644
2645 <i>; Emulate an unconditional br instruction</i>
2646 switch i32 0, label %dest [ ]
2647
2648 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2649 switch i32 %val, label %otherwise [ i32 0, label %onzero
2650 i32 1, label %onone
2651 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2652</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654</div>
2655
2656<!-- _______________________________________________________________________ -->
2657<div class="doc_subsubsection">
2658 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2659</div>
2660
2661<div class="doc_text">
2662
2663<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2664<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2665 &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]2666 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2667</pre>
2668
2669<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2671 function, with the possibility of control flow transfer to either the
2672 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2673 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2674 control flow will return to the "normal" label. If the callee (or any
2675 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2676 instruction, control is interrupted and continued at the dynamically nearest
2677 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2678
2679<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680<p>This instruction requires several arguments:</p>
2681
2682<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2683 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2684 convention</a> the call should use. If none is specified, the call
2685 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2686
2687 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2688 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2689 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2691 <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]2692 function value being invoked. In most cases, this is a direct function
2693 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2694 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695
2696 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2697 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2698
2699 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2700 signature argument types. If the function signature indicates the
2701 function accepts a variable number of arguments, the extra arguments can
2702 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703
2704 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2705 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2706
2707 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2708 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2709
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2710 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2711 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2712 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2713</ol>
2714
2715<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2716<p>This instruction is designed to operate as a standard
2717 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2718 primary difference is that it establishes an association with a label, which
2719 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2720
2721<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2722 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2723 exception. Additionally, this is important for implementation of
2724 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2725
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2726<p>For the purposes of the SSA form, the definition of the value returned by the
2727 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2728 block to the "normal" label. If the callee unwinds then no return value is
2729 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2731<h5>Example:</h5>
2732<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2733 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2734 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2735 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736 unwind label %TestCleanup <i>; {i32}:retval set</i>
2737</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2739</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2740
2741<!-- _______________________________________________________________________ -->
2742
2743<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2744Instruction</a> </div>
2745
2746<div class="doc_text">
2747
2748<h5>Syntax:</h5>
2749<pre>
2750 unwind
2751</pre>
2752
2753<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2754<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2755 at the first callee in the dynamic call stack which used
2756 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2757 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2758
2759<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2760<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2761 immediately halt. The dynamic call stack is then searched for the
2762 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2763 Once found, execution continues at the "exceptional" destination block
2764 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2765 instruction in the dynamic call chain, undefined behavior results.</p>
2766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2767</div>
2768
2769<!-- _______________________________________________________________________ -->
2770
2771<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2772Instruction</a> </div>
2773
2774<div class="doc_text">
2775
2776<h5>Syntax:</h5>
2777<pre>
2778 unreachable
2779</pre>
2780
2781<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2783 instruction is used to inform the optimizer that a particular portion of the
2784 code is not reachable. This can be used to indicate that the code after a
2785 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2786
2787<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2788<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2790</div>
2791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792<!-- ======================================================================= -->
2793<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2796
2797<p>Binary operators are used to do most of the computation in a program. They
2798 require two operands of the same type, execute an operation on them, and
2799 produce a single value. The operands might represent multiple data, as is
2800 the case with the <a href="#t_vector">vector</a> data type. The result value
2801 has the same type as its operands.</p>
2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2805</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2808<div class="doc_subsubsection">
2809 <a name="i_add">'<tt>add</tt>' Instruction</a>
2810</div>
2811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2814<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2815<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2816 &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]2817 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2818 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2819 &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]2820</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2822<h5>Overview:</h5>
2823<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2824
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2825<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2826<p>The two arguments to the '<tt>add</tt>' instruction must
2827 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2828 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2830<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2831<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2832
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2833<p>If the sum has unsigned overflow, the result returned is the mathematical
2834 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]2835
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2836<p>Because LLVM integers use a two's complement representation, this instruction
2837 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2838
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2839<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2840 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2841 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2842 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2845<pre>
2846 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2847</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2849</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2851<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2852<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2853 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2854</div>
2855
2856<div class="doc_text">
2857
2858<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2859<pre>
2860 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2861</pre>
2862
2863<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2864<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2865
2866<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2867<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2868 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2869 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2870
2871<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2872<p>The value produced is the floating point sum of the two operands.</p>
2873
2874<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2875<pre>
2876 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2877</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2878
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2879</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2880
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2881<!-- _______________________________________________________________________ -->
2882<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2883 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2884</div>
2885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2889<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2890 &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]2891 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2892 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2893 &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]2894</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<h5>Overview:</h5>
2897<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2898 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2899
2900<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2901 '<tt>neg</tt>' instruction present in most other intermediate
2902 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2904<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2905<p>The two arguments to the '<tt>sub</tt>' instruction must
2906 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2907 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2909<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2910<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2911
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2912<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2913 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2914 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2915
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916<p>Because LLVM integers use a two's complement representation, this instruction
2917 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2918
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2919<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2920 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2921 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2922 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2924<h5>Example:</h5>
2925<pre>
2926 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2927 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2928</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2933<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2934 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2935</div>
2936
2937<div class="doc_text">
2938
2939<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2940<pre>
2941 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2942</pre>
2943
2944<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2945<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2946 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2947
2948<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2949 '<tt>fneg</tt>' instruction present in most other intermediate
2950 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2951
2952<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2953<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2954 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2955 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2956
2957<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2958<p>The value produced is the floating point difference of the two operands.</p>
2959
2960<h5>Example:</h5>
2961<pre>
2962 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2963 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2964</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2965
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2966</div>
2967
2968<!-- _______________________________________________________________________ -->
2969<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2970 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2971</div>
2972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2973<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2975<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2976<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2977 &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]2978 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2979 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2980 &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]2981</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2982
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2983<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2984<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2986<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2987<p>The two arguments to the '<tt>mul</tt>' instruction must
2988 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2989 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2991<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2992<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2993
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2994<p>If the result of the multiplication has unsigned overflow, the result
2995 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2996 width of the result.</p>
2997
2998<p>Because LLVM integers use a two's complement representation, and the result
2999 is the same width as the operands, this instruction returns the correct
3000 result for both signed and unsigned integers. If a full product
3001 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3002 be sign-extended or zero-extended as appropriate to the width of the full
3003 product.</p>
3004
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3005<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3006 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3007 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3008 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3009
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3010<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3011<pre>
3012 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3013</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3014
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3015</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3016
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3017<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3018<div class="doc_subsubsection">
3019 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3020</div>
3021
3022<div class="doc_text">
3023
3024<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3025<pre>
3026 &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]3027</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3028
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3029<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3031
3032<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3033<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3034 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3035 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3036
3037<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3038<p>The value produced is the floating point product of the two operands.</p>
3039
3040<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3041<pre>
3042 &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]3043</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3044
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3045</div>
3046
3047<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3048<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3049</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3051<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3053<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3054<pre>
3055 &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]3056</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3058<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3059<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3061<h5>Arguments:</h5>
3062<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3063 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3064 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3066<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3067<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3068
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3069<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3071
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3072<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3074<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3075<pre>
3076 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3077</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3079</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3081<!-- _______________________________________________________________________ -->
3082<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3083</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3085<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3087<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3088<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3089 &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]3090 &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]3091</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3093<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3094<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3095
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3096<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3097<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3098 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3099 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3100
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3101<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3102<p>The value produced is the signed integer quotient of the two operands rounded
3103 towards zero.</p>
3104
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3105<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3106 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3107
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3108<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3109 undefined behavior; this is a rare case, but can occur, for example, by doing
3110 a 32-bit division of -2147483648 by -1.</p>
3111
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3112<p>If the <tt>exact</tt> keyword is present, the result value of the
3113 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3114 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3117<pre>
3118 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3121</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3123<!-- _______________________________________________________________________ -->
3124<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3125Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3129<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3130<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3131 &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]3132</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3133
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3134<h5>Overview:</h5>
3135<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137<h5>Arguments:</h5>
3138<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3139 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3140 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3142<h5>Semantics:</h5>
3143<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3145<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3146<pre>
3147 &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]3148</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3149
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3150</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3152<!-- _______________________________________________________________________ -->
3153<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3154</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3156<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3158<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3159<pre>
3160 &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]3161</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3163<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3165 division of its two arguments.</p>
3166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3169 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3170 values. Both arguments must have identical types.</p>
3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<h5>Semantics:</h5>
3173<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3174 This instruction always performs an unsigned division to get the
3175 remainder.</p>
3176
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3177<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3179
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3180<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3182<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3183<pre>
3184 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185</pre>
3186
3187</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3190<div class="doc_subsubsection">
3191 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3192</div>
3193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3194<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3195
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3196<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3197<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3198 &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]3199</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3202<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3203 division of its two operands. This instruction can also take
3204 <a href="#t_vector">vector</a> versions of the values in which case the
3205 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3206
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3207<h5>Arguments:</h5>
3208<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3209 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3210 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3212<h5>Semantics:</h5>
3213<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3214 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3215 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3216 a value. For more information about the difference,
3217 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3218 Math Forum</a>. For a table of how this is implemented in various languages,
3219 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3220 Wikipedia: modulo operation</a>.</p>
3221
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3222<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3223 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3224
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3225<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3226 Overflow also leads to undefined behavior; this is a rare case, but can
3227 occur, for example, by taking the remainder of a 32-bit division of
3228 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3229 lets srem be implemented using instructions that return both the result of
3230 the division and the remainder.)</p>
3231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3232<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3233<pre>
3234 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3235</pre>
3236
3237</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3239<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3240<div class="doc_subsubsection">
3241 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3245<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3246<pre>
3247 &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]3248</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3249
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3250<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3251<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3252 its two operands.</p>
3253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3254<h5>Arguments:</h5>
3255<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3256 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3257 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3259<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3260<p>This instruction returns the <i>remainder</i> of a division. The remainder
3261 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3263<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3264<pre>
3265 &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]3266</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3268</div>
3269
3270<!-- ======================================================================= -->
3271<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3272Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3274<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3275
3276<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3277 program. They are generally very efficient instructions and can commonly be
3278 strength reduced from other instructions. They require two operands of the
3279 same type, execute an operation on them, and produce a single value. The
3280 resulting value is the same type as its operands.</p>
3281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3282</div>
3283
3284<!-- _______________________________________________________________________ -->
3285<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3286Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3288<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3290<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3291<pre>
3292 &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]3293</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3295<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3296<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3297 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3298
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3299<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3300<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3301 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3302 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3304<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3305<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3306 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3307 is (statically or dynamically) negative or equal to or larger than the number
3308 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3309 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3310 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3311
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3312<h5>Example:</h5>
3313<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3314 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3315 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3316 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3317 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3318 &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]3319</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3321</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3323<!-- _______________________________________________________________________ -->
3324<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3325Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3329<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3330<pre>
3331 &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]3332</pre>
3333
3334<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3335<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3336 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3337
3338<h5>Arguments:</h5>
3339<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3340 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3341 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3342
3343<h5>Semantics:</h5>
3344<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3345 significant bits of the result will be filled with zero bits after the shift.
3346 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3347 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3348 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3349 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350
3351<h5>Example:</h5>
3352<pre>
3353 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3354 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3355 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3356 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3357 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3358 &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]3359</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361</div>
3362
3363<!-- _______________________________________________________________________ -->
3364<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3365Instruction</a> </div>
3366<div class="doc_text">
3367
3368<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3369<pre>
3370 &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]3371</pre>
3372
3373<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3374<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3375 operand shifted to the right a specified number of bits with sign
3376 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377
3378<h5>Arguments:</h5>
3379<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3380 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3381 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3382
3383<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3384<p>This instruction always performs an arithmetic shift right operation, The
3385 most significant bits of the result will be filled with the sign bit
3386 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3387 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3388 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3389 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390
3391<h5>Example:</h5>
3392<pre>
3393 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3394 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3395 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3396 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3397 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3398 &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]3399</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3401</div>
3402
3403<!-- _______________________________________________________________________ -->
3404<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3405Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3407<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3409<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3410<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3411 &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]3412</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3414<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3415<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3416 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3418<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3419<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3420 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3421 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3423<h5>Semantics:</h5>
3424<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426<table border="1" cellspacing="0" cellpadding="4">
3427 <tbody>
3428 <tr>
3429 <td>In0</td>
3430 <td>In1</td>
3431 <td>Out</td>
3432 </tr>
3433 <tr>
3434 <td>0</td>
3435 <td>0</td>
3436 <td>0</td>
3437 </tr>
3438 <tr>
3439 <td>0</td>
3440 <td>1</td>
3441 <td>0</td>
3442 </tr>
3443 <tr>
3444 <td>1</td>
3445 <td>0</td>
3446 <td>0</td>
3447 </tr>
3448 <tr>
3449 <td>1</td>
3450 <td>1</td>
3451 <td>1</td>
3452 </tr>
3453 </tbody>
3454</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3456<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3457<pre>
3458 &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]3459 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3460 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3461</pre>
3462</div>
3463<!-- _______________________________________________________________________ -->
3464<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3465
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466<div class="doc_text">
3467
3468<h5>Syntax:</h5>
3469<pre>
3470 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3471</pre>
3472
3473<h5>Overview:</h5>
3474<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3475 two operands.</p>
3476
3477<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3478<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3479 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3480 values. Both arguments must have identical types.</p>
3481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482<h5>Semantics:</h5>
3483<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485<table border="1" cellspacing="0" cellpadding="4">
3486 <tbody>
3487 <tr>
3488 <td>In0</td>
3489 <td>In1</td>
3490 <td>Out</td>
3491 </tr>
3492 <tr>
3493 <td>0</td>
3494 <td>0</td>
3495 <td>0</td>
3496 </tr>
3497 <tr>
3498 <td>0</td>
3499 <td>1</td>
3500 <td>1</td>
3501 </tr>
3502 <tr>
3503 <td>1</td>
3504 <td>0</td>
3505 <td>1</td>
3506 </tr>
3507 <tr>
3508 <td>1</td>
3509 <td>1</td>
3510 <td>1</td>
3511 </tr>
3512 </tbody>
3513</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3515<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3516<pre>
3517 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3519 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3520</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3522</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3524<!-- _______________________________________________________________________ -->
3525<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3526Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3530<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3531<pre>
3532 &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]3533</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3535<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3536<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3537 its two operands. The <tt>xor</tt> is used to implement the "one's
3538 complement" operation, which is the "~" operator in C.</p>
3539
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3540<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3541<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3542 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3543 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3545<h5>Semantics:</h5>
3546<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3548<table border="1" cellspacing="0" cellpadding="4">
3549 <tbody>
3550 <tr>
3551 <td>In0</td>
3552 <td>In1</td>
3553 <td>Out</td>
3554 </tr>
3555 <tr>
3556 <td>0</td>
3557 <td>0</td>
3558 <td>0</td>
3559 </tr>
3560 <tr>
3561 <td>0</td>
3562 <td>1</td>
3563 <td>1</td>
3564 </tr>
3565 <tr>
3566 <td>1</td>
3567 <td>0</td>
3568 <td>1</td>
3569 </tr>
3570 <tr>
3571 <td>1</td>
3572 <td>1</td>
3573 <td>0</td>
3574 </tr>
3575 </tbody>
3576</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3578<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3579<pre>
3580 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3581 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3582 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3583 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3584</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3586</div>
3587
3588<!-- ======================================================================= -->
3589<div class="doc_subsection">
3590 <a name="vectorops">Vector Operations</a>
3591</div>
3592
3593<div class="doc_text">
3594
3595<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3596 target-independent manner. These instructions cover the element-access and
3597 vector-specific operations needed to process vectors effectively. While LLVM
3598 does directly support these vector operations, many sophisticated algorithms
3599 will want to use target-specific intrinsics to take full advantage of a
3600 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601
3602</div>
3603
3604<!-- _______________________________________________________________________ -->
3605<div class="doc_subsubsection">
3606 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3607</div>
3608
3609<div class="doc_text">
3610
3611<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3612<pre>
3613 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3614</pre>
3615
3616<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3617<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3618 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3619
3620
3621<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3622<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3623 of <a href="#t_vector">vector</a> type. The second operand is an index
3624 indicating the position from which to extract the element. The index may be
3625 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626
3627<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3628<p>The result is a scalar of the same type as the element type of
3629 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3630 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3631 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3632
3633<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634<pre>
3635 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3636</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3638</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3639
3640<!-- _______________________________________________________________________ -->
3641<div class="doc_subsubsection">
3642 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3643</div>
3644
3645<div class="doc_text">
3646
3647<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3649 &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]3650</pre>
3651
3652<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3653<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3654 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3655
3656<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3657<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3658 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3659 whose type must equal the element type of the first operand. The third
3660 operand is an index indicating the position at which to insert the value.
3661 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3662
3663<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3664<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3665 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3666 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3667 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3668
3669<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3670<pre>
3671 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3672</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3674</div>
3675
3676<!-- _______________________________________________________________________ -->
3677<div class="doc_subsubsection">
3678 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3679</div>
3680
3681<div class="doc_text">
3682
3683<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3684<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3685 &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]3686</pre>
3687
3688<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3689<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3690 from two input vectors, returning a vector with the same element type as the
3691 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3692
3693<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3694<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3695 with types that match each other. The third argument is a shuffle mask whose
3696 element type is always 'i32'. The result of the instruction is a vector
3697 whose length is the same as the shuffle mask and whose element type is the
3698 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3699
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3700<p>The shuffle mask operand is required to be a constant vector with either
3701 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702
3703<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3704<p>The elements of the two input vectors are numbered from left to right across
3705 both of the vectors. The shuffle mask operand specifies, for each element of
3706 the result vector, which element of the two input vectors the result element
3707 gets. The element selector may be undef (meaning "don't care") and the
3708 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3709
3710<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3711<pre>
3712 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3713 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3714 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3715 &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.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3716 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3717 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3718 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3719 &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]3720</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3721
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3722</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3723
3724<!-- ======================================================================= -->
3725<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3726 <a name="aggregateops">Aggregate Operations</a>
3727</div>
3728
3729<div class="doc_text">
3730
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3731<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3732
3733</div>
3734
3735<!-- _______________________________________________________________________ -->
3736<div class="doc_subsubsection">
3737 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3738</div>
3739
3740<div class="doc_text">
3741
3742<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3743<pre>
3744 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3745</pre>
3746
3747<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3748<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3749 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3750
3751<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3752<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3753 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3754 operands are constant indices to specify which value to extract in a similar
3755 manner as indices in a
3756 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3757
3758<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3759<p>The result is the value at the position in the aggregate specified by the
3760 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3761
3762<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3763<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3764 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3765</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3766
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3767</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3768
3769<!-- _______________________________________________________________________ -->
3770<div class="doc_subsubsection">
3771 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3772</div>
3773
3774<div class="doc_text">
3775
3776<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3777<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3778 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3779</pre>
3780
3781<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3782<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3783 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3784
3785
3786<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3787<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3788 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3789 second operand is a first-class value to insert. The following operands are
3790 constant indices indicating the position at which to insert the value in a
3791 similar manner as indices in a
3792 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3793 value to insert must have the same type as the value identified by the
3794 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3795
3796<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3797<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3798 that of <tt>val</tt> except that the value at the position specified by the
3799 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3800
3801<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3802<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3803 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3804</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3805
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3806</div>
3807
3808
3809<!-- ======================================================================= -->
3810<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3811 <a name="memoryops">Memory Access and Addressing Operations</a>
3812</div>
3813
3814<div class="doc_text">
3815
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3816<p>A key design point of an SSA-based representation is how it represents
3817 memory. In LLVM, no memory locations are in SSA form, which makes things
3818 very simple. This section describes how to read, write, allocate, and free
3819 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3820
3821</div>
3822
3823<!-- _______________________________________________________________________ -->
3824<div class="doc_subsubsection">
3825 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3826</div>
3827
3828<div class="doc_text">
3829
3830<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3831<pre>
3832 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3833</pre>
3834
3835<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3836<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3837 returns a pointer to it. The object is always allocated in the generic
3838 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3839
3840<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3841<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3842 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3843 system and returns a pointer of the appropriate type to the program. If
3844 "NumElements" is specified, it is the number of elements allocated, otherwise
3845 "NumElements" is defaulted to be one. If a constant alignment is specified,
3846 the value result of the allocation is guaranteed to be aligned to at least
3847 that boundary. If not specified, or if zero, the target can choose to align
3848 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3849
3850<p>'<tt>type</tt>' must be a sized type.</p>
3851
3852<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3853<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3854 pointer is returned. The result of a zero byte allocation is undefined. The
3855 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3856
3857<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3858<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3859 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3860
3861 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3862 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3863 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3864 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3865 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3866</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3867
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3868<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3870</div>
3871
3872<!-- _______________________________________________________________________ -->
3873<div class="doc_subsubsection">
3874 <a name="i_free">'<tt>free</tt>' Instruction</a>
3875</div>
3876
3877<div class="doc_text">
3878
3879<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3880<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3881 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3882</pre>
3883
3884<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3885<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3886 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3887
3888<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3889<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3890 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3891
3892<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3893<p>Access to the memory pointed to by the pointer is no longer defined after
3894 this instruction executes. If the pointer is null, the operation is a
3895 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3896
3897<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3899 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3900 free [4 x i8]* %array
3901</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3903</div>
3904
3905<!-- _______________________________________________________________________ -->
3906<div class="doc_subsubsection">
3907 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3908</div>
3909
3910<div class="doc_text">
3911
3912<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913<pre>
3914 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3915</pre>
3916
3917<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3918<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3919 currently executing function, to be automatically released when this function
3920 returns to its caller. The object is always allocated in the generic address
3921 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3922
3923<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3924<p>The '<tt>alloca</tt>' instruction
3925 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3926 runtime stack, returning a pointer of the appropriate type to the program.
3927 If "NumElements" is specified, it is the number of elements allocated,
3928 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3929 specified, the value result of the allocation is guaranteed to be aligned to
3930 at least that boundary. If not specified, or if zero, the target can choose
3931 to align the allocation on any convenient boundary compatible with the
3932 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3933
3934<p>'<tt>type</tt>' may be any sized type.</p>
3935
3936<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3937<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3938 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3939 memory is automatically released when the function returns. The
3940 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3941 variables that must have an address available. When the function returns
3942 (either with the <tt><a href="#i_ret">ret</a></tt>
3943 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3944 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3945
3946<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3947<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3948 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3949 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3950 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3951 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3954</div>
3955
3956<!-- _______________________________________________________________________ -->
3957<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3958Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3962<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3963<pre>
3964 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3965 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3966</pre>
3967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3968<h5>Overview:</h5>
3969<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3971<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3972<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3973 from which to load. The pointer must point to
3974 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3975 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3976 number or order of execution of this <tt>load</tt> with other
3977 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3978 instructions. </p>
3979
3980<p>The optional constant "align" argument specifies the alignment of the
3981 operation (that is, the alignment of the memory address). A value of 0 or an
3982 omitted "align" argument means that the operation has the preferential
3983 alignment for the target. It is the responsibility of the code emitter to
3984 ensure that the alignment information is correct. Overestimating the
3985 alignment results in an undefined behavior. Underestimating the alignment may
3986 produce less efficient code. An alignment of 1 is always safe.</p>
3987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3988<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3989<p>The location of memory pointed to is loaded. If the value being loaded is of
3990 scalar type then the number of bytes read does not exceed the minimum number
3991 of bytes needed to hold all bits of the type. For example, loading an
3992 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3993 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3994 is undefined if the value was not originally written using a store of the
3995 same type.</p>
3996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3997<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3998<pre>
3999 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4000 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4001 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4002</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4004</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4006<!-- _______________________________________________________________________ -->
4007<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4008Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4009
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4010<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4012<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4013<pre>
4014 store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4016</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4017
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4018<h5>Overview:</h5>
4019<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4021<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4022<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4023 and an address at which to store it. The type of the
4024 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4025 the <a href="#t_firstclass">first class</a> type of the
4026 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4027 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4028 or order of execution of this <tt>store</tt> with other
4029 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4030 instructions.</p>
4031
4032<p>The optional constant "align" argument specifies the alignment of the
4033 operation (that is, the alignment of the memory address). A value of 0 or an
4034 omitted "align" argument means that the operation has the preferential
4035 alignment for the target. It is the responsibility of the code emitter to
4036 ensure that the alignment information is correct. Overestimating the
4037 alignment results in an undefined behavior. Underestimating the alignment may
4038 produce less efficient code. An alignment of 1 is always safe.</p>
4039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4040<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4041<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4042 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4043 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4044 does not exceed the minimum number of bytes needed to hold all bits of the
4045 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4046 writing a value of a type like <tt>i20</tt> with a size that is not an
4047 integral number of bytes, it is unspecified what happens to the extra bits
4048 that do not belong to the type, but they will typically be overwritten.</p>
4049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4050<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4051<pre>
4052 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4053 store i32 3, i32* %ptr <i>; yields {void}</i>
4054 %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]4055</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057</div>
4058
4059<!-- _______________________________________________________________________ -->
4060<div class="doc_subsubsection">
4061 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4062</div>
4063
4064<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066<h5>Syntax:</h5>
4067<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4068 &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]4069 &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]4070</pre>
4071
4072<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4073<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4074 subelement of an aggregate data structure. It performs address calculation
4075 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076
4077<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4078<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4079 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4080 elements of the aggregate object are indexed. The interpretation of each
4081 index is dependent on the type being indexed into. The first index always
4082 indexes the pointer value given as the first argument, the second index
4083 indexes a value of the type pointed to (not necessarily the value directly
4084 pointed to, since the first index can be non-zero), etc. The first type
4085 indexed into must be a pointer value, subsequent types can be arrays, vectors
4086 and structs. Note that subsequent types being indexed into can never be
4087 pointers, since that would require loading the pointer before continuing
4088 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4089
4090<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4091 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4092 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4093 vector, integers of any width are allowed, and they are not required to be
4094 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4096<p>For example, let's consider a C code fragment and how it gets compiled to
4097 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4098
4099<div class="doc_code">
4100<pre>
4101struct RT {
4102 char A;
4103 int B[10][20];
4104 char C;
4105};
4106struct ST {
4107 int X;
4108 double Y;
4109 struct RT Z;
4110};
4111
4112int *foo(struct ST *s) {
4113 return &amp;s[1].Z.B[5][13];
4114}
4115</pre>
4116</div>
4117
4118<p>The LLVM code generated by the GCC frontend is:</p>
4119
4120<div class="doc_code">
4121<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4122%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4123%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4124
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4125define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126entry:
4127 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4128 ret i32* %reg
4129}
4130</pre>
4131</div>
4132
4133<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134<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]4135 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4136 }</tt>' type, a structure. The second index indexes into the third element
4137 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4138 i8 }</tt>' type, another structure. The third index indexes into the second
4139 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4140 array. The two dimensions of the array are subscripted into, yielding an
4141 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4142 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4143
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4144<p>Note that it is perfectly legal to index partially through a structure,
4145 returning a pointer to an inner element. Because of this, the LLVM code for
4146 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147
4148<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4149 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4150 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4151 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4152 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4153 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4154 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4155 ret i32* %t5
4156 }
4157</pre>
4158
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4159<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4160 <tt>getelementptr</tt> is undefined if the base pointer is not an
4161 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4162 that would be formed by successive addition of the offsets implied by the
4163 indices to the base address with infinitely precise arithmetic are not an
4164 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4165 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4166 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4167
4168<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4169 the base address with silently-wrapping two's complement arithmetic, and
4170 the result value of the <tt>getelementptr</tt> may be outside the object
4171 pointed to by the base pointer. The result value may not necessarily be
4172 used to access memory though, even if it happens to point into allocated
4173 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4174 section for more information.</p>
4175
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4176<p>The getelementptr instruction is often confusing. For some more insight into
4177 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178
4179<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4180<pre>
4181 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4182 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4183 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4184 %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]4185 <i>; yields i8*:eptr</i>
4186 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4187 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4188 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4191</div>
4192
4193<!-- ======================================================================= -->
4194<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4195</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4197<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4199<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4200 which all take a single operand and a type. They perform various bit
4201 conversions on the operand.</p>
4202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4203</div>
4204
4205<!-- _______________________________________________________________________ -->
4206<div class="doc_subsubsection">
4207 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4208</div>
4209<div class="doc_text">
4210
4211<h5>Syntax:</h5>
4212<pre>
4213 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4214</pre>
4215
4216<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4217<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4218 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4219
4220<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4221<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4222 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4223 size and type of the result, which must be
4224 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4225 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4226 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227
4228<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4229<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4230 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4231 source size must be larger than the destination size, <tt>trunc</tt> cannot
4232 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4233
4234<h5>Example:</h5>
4235<pre>
4236 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4237 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4238 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4239</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241</div>
4242
4243<!-- _______________________________________________________________________ -->
4244<div class="doc_subsubsection">
4245 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4246</div>
4247<div class="doc_text">
4248
4249<h5>Syntax:</h5>
4250<pre>
4251 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4252</pre>
4253
4254<h5>Overview:</h5>
4255<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4256 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4257
4258
4259<h5>Arguments:</h5>
4260<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]4261 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4262 also be of <a href="#t_integer">integer</a> type. The bit size of the
4263 <tt>value</tt> must be smaller than the bit size of the destination type,
4264 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265
4266<h5>Semantics:</h5>
4267<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]4268 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4269
4270<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4271
4272<h5>Example:</h5>
4273<pre>
4274 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4275 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4276</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4278</div>
4279
4280<!-- _______________________________________________________________________ -->
4281<div class="doc_subsubsection">
4282 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4283</div>
4284<div class="doc_text">
4285
4286<h5>Syntax:</h5>
4287<pre>
4288 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4289</pre>
4290
4291<h5>Overview:</h5>
4292<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4293
4294<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4295<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4296 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4297 also be of <a href="#t_integer">integer</a> type. The bit size of the
4298 <tt>value</tt> must be smaller than the bit size of the destination type,
4299 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4300
4301<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4302<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4303 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4304 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4305
4306<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4307
4308<h5>Example:</h5>
4309<pre>
4310 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4311 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4312</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4313
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4314</div>
4315
4316<!-- _______________________________________________________________________ -->
4317<div class="doc_subsubsection">
4318 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4319</div>
4320
4321<div class="doc_text">
4322
4323<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4324<pre>
4325 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4326</pre>
4327
4328<h5>Overview:</h5>
4329<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4330 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4331
4332<h5>Arguments:</h5>
4333<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4334 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4335 to cast it to. The size of <tt>value</tt> must be larger than the size of
4336 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4337 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4338
4339<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4340<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4341 <a href="#t_floating">floating point</a> type to a smaller
4342 <a href="#t_floating">floating point</a> type. If the value cannot fit
4343 within the destination type, <tt>ty2</tt>, then the results are
4344 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4345
4346<h5>Example:</h5>
4347<pre>
4348 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4349 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4350</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4351
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4352</div>
4353
4354<!-- _______________________________________________________________________ -->
4355<div class="doc_subsubsection">
4356 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4357</div>
4358<div class="doc_text">
4359
4360<h5>Syntax:</h5>
4361<pre>
4362 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4363</pre>
4364
4365<h5>Overview:</h5>
4366<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]4367 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4368
4369<h5>Arguments:</h5>
4370<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4371 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4372 a <a href="#t_floating">floating point</a> type to cast it to. The source
4373 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4374
4375<h5>Semantics:</h5>
4376<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4377 <a href="#t_floating">floating point</a> type to a larger
4378 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4379 used to make a <i>no-op cast</i> because it always changes bits. Use
4380 <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]4381
4382<h5>Example:</h5>
4383<pre>
4384 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4385 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4386</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4387
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4388</div>
4389
4390<!-- _______________________________________________________________________ -->
4391<div class="doc_subsubsection">
4392 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4393</div>
4394<div class="doc_text">
4395
4396<h5>Syntax:</h5>
4397<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4398 &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]4399</pre>
4400
4401<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4402<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4403 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4404
4405<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4406<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4407 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4408 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4409 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4410 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4411
4412<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4413<p>The '<tt>fptoui</tt>' instruction converts its
4414 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4415 towards zero) unsigned integer value. If the value cannot fit
4416 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4418<h5>Example:</h5>
4419<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4420 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4421 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4422 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4423</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4425</div>
4426
4427<!-- _______________________________________________________________________ -->
4428<div class="doc_subsubsection">
4429 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4430</div>
4431<div class="doc_text">
4432
4433<h5>Syntax:</h5>
4434<pre>
4435 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4436</pre>
4437
4438<h5>Overview:</h5>
4439<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4440 <a href="#t_floating">floating point</a> <tt>value</tt> to
4441 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4444<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4445 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4446 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4447 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4448 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449
4450<h5>Semantics:</h5>
4451<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4452 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4453 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4454 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456<h5>Example:</h5>
4457<pre>
4458 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4459 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4460 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4461</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4463</div>
4464
4465<!-- _______________________________________________________________________ -->
4466<div class="doc_subsubsection">
4467 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4468</div>
4469<div class="doc_text">
4470
4471<h5>Syntax:</h5>
4472<pre>
4473 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4474</pre>
4475
4476<h5>Overview:</h5>
4477<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4478 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4481<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]4482 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4483 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4484 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4485 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486
4487<h5>Semantics:</h5>
4488<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4489 integer quantity and converts it to the corresponding floating point
4490 value. If the value cannot fit in the floating point value, the results are
4491 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4493<h5>Example:</h5>
4494<pre>
4495 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4496 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499</div>
4500
4501<!-- _______________________________________________________________________ -->
4502<div class="doc_subsubsection">
4503 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4504</div>
4505<div class="doc_text">
4506
4507<h5>Syntax:</h5>
4508<pre>
4509 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4510</pre>
4511
4512<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4513<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4514 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4515
4516<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4517<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]4518 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4519 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4520 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4521 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522
4523<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4524<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4525 quantity and converts it to the corresponding floating point value. If the
4526 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4527
4528<h5>Example:</h5>
4529<pre>
4530 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4531 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4532</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534</div>
4535
4536<!-- _______________________________________________________________________ -->
4537<div class="doc_subsubsection">
4538 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4539</div>
4540<div class="doc_text">
4541
4542<h5>Syntax:</h5>
4543<pre>
4544 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4545</pre>
4546
4547<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4548<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4549 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4550
4551<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4552<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4553 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4554 <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]4555
4556<h5>Semantics:</h5>
4557<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4558 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4559 truncating or zero extending that value to the size of the integer type. If
4560 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4561 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4562 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4563 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4564
4565<h5>Example:</h5>
4566<pre>
4567 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4568 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4569</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4570
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4571</div>
4572
4573<!-- _______________________________________________________________________ -->
4574<div class="doc_subsubsection">
4575 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4576</div>
4577<div class="doc_text">
4578
4579<h5>Syntax:</h5>
4580<pre>
4581 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4582</pre>
4583
4584<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4585<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4586 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587
4588<h5>Arguments:</h5>
4589<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4590 value to cast, and a type to cast it to, which must be a
4591 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4592
4593<h5>Semantics:</h5>
4594<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4595 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4596 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4597 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4598 than the size of a pointer then a zero extension is done. If they are the
4599 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4600
4601<h5>Example:</h5>
4602<pre>
4603 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4604 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4605 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4606</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4608</div>
4609
4610<!-- _______________________________________________________________________ -->
4611<div class="doc_subsubsection">
4612 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4613</div>
4614<div class="doc_text">
4615
4616<h5>Syntax:</h5>
4617<pre>
4618 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4619</pre>
4620
4621<h5>Overview:</h5>
4622<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4623 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624
4625<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4626<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4627 non-aggregate first class value, and a type to cast it to, which must also be
4628 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4629 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4630 identical. If the source type is a pointer, the destination type must also be
4631 a pointer. This instruction supports bitwise conversion of vectors to
4632 integers and to vectors of other types (as long as they have the same
4633 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4634
4635<h5>Semantics:</h5>
4636<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4637 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4638 this conversion. The conversion is done as if the <tt>value</tt> had been
4639 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4640 be converted to other pointer types with this instruction. To convert
4641 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4642 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4643
4644<h5>Example:</h5>
4645<pre>
4646 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4647 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4648 %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]4649</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651</div>
4652
4653<!-- ======================================================================= -->
4654<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4656<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4657
4658<p>The instructions in this category are the "miscellaneous" instructions, which
4659 defy better classification.</p>
4660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4661</div>
4662
4663<!-- _______________________________________________________________________ -->
4664<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4665</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4666
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4667<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4670<pre>
4671 &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]4672</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4674<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4675<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4676 boolean values based on comparison of its two integer, integer vector, or
4677 pointer operands.</p>
4678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4679<h5>Arguments:</h5>
4680<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4681 the condition code indicating the kind of comparison to perform. It is not a
4682 value, just a keyword. The possible condition code are:</p>
4683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4684<ol>
4685 <li><tt>eq</tt>: equal</li>
4686 <li><tt>ne</tt>: not equal </li>
4687 <li><tt>ugt</tt>: unsigned greater than</li>
4688 <li><tt>uge</tt>: unsigned greater or equal</li>
4689 <li><tt>ult</tt>: unsigned less than</li>
4690 <li><tt>ule</tt>: unsigned less or equal</li>
4691 <li><tt>sgt</tt>: signed greater than</li>
4692 <li><tt>sge</tt>: signed greater or equal</li>
4693 <li><tt>slt</tt>: signed less than</li>
4694 <li><tt>sle</tt>: signed less or equal</li>
4695</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4698 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4699 typed. They must also be identical types.</p>
4700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4701<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4702<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4703 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4704 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]4705 result, as follows:</p>
4706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4707<ol>
4708 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4709 <tt>false</tt> otherwise. No sign interpretation is necessary or
4710 performed.</li>
4711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4712 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4713 <tt>false</tt> otherwise. No sign interpretation is necessary or
4714 performed.</li>
4715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4716 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4717 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4719 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4720 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4721 to <tt>op2</tt>.</li>
4722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4729 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4730 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4733 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4734 to <tt>op2</tt>.</li>
4735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4736 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4737 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4739 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4740 <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]4741</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4743<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4744 values are compared as if they were integers.</p>
4745
4746<p>If the operands are integer vectors, then they are compared element by
4747 element. The result is an <tt>i1</tt> vector with the same number of elements
4748 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4749
4750<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4751<pre>
4752 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4754 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4755 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4756 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4757 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4758</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4759
4760<p>Note that the code generator does not yet support vector types with
4761 the <tt>icmp</tt> instruction.</p>
4762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4767</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4769<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4771<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4772<pre>
4773 &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]4774</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4775
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4776<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4777<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4778 values based on comparison of its operands.</p>
4779
4780<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]4781(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4782
4783<p>If the operands are floating point vectors, then the result type is a vector
4784 of boolean with the same number of elements as the operands being
4785 compared.</p>
4786
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4787<h5>Arguments:</h5>
4788<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4789 the condition code indicating the kind of comparison to perform. It is not a
4790 value, just a keyword. The possible condition code are:</p>
4791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4792<ol>
4793 <li><tt>false</tt>: no comparison, always returns false</li>
4794 <li><tt>oeq</tt>: ordered and equal</li>
4795 <li><tt>ogt</tt>: ordered and greater than </li>
4796 <li><tt>oge</tt>: ordered and greater than or equal</li>
4797 <li><tt>olt</tt>: ordered and less than </li>
4798 <li><tt>ole</tt>: ordered and less than or equal</li>
4799 <li><tt>one</tt>: ordered and not equal</li>
4800 <li><tt>ord</tt>: ordered (no nans)</li>
4801 <li><tt>ueq</tt>: unordered or equal</li>
4802 <li><tt>ugt</tt>: unordered or greater than </li>
4803 <li><tt>uge</tt>: unordered or greater than or equal</li>
4804 <li><tt>ult</tt>: unordered or less than </li>
4805 <li><tt>ule</tt>: unordered or less than or equal</li>
4806 <li><tt>une</tt>: unordered or not equal</li>
4807 <li><tt>uno</tt>: unordered (either nans)</li>
4808 <li><tt>true</tt>: no comparison, always returns true</li>
4809</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4811<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4812 <i>unordered</i> means that either operand may be a QNAN.</p>
4813
4814<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4815 a <a href="#t_floating">floating point</a> type or
4816 a <a href="#t_vector">vector</a> of floating point type. They must have
4817 identical types.</p>
4818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4819<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4820<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4821 according to the condition code given as <tt>cond</tt>. If the operands are
4822 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4823 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4824 follows:</p>
4825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4826<ol>
4827 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4828
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4829 <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]4830 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4831
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4832 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4833 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4835 <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]4836 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838 <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]4839 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4841 <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]4842 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844 <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]4845 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847 <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]4848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4849 <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]4850 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4851
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4852 <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]4853 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4855 <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]4856 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4858 <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]4859 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4860
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4861 <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]4862 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4864 <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]4865 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867 <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]4868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4869 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4870</ol>
4871
4872<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4873<pre>
4874 &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]4875 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4876 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4877 &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]4878</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4879
4880<p>Note that the code generator does not yet support vector types with
4881 the <tt>fcmp</tt> instruction.</p>
4882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4883</div>
4884
4885<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4886<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4887 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4888</div>
4889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4890<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4892<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4893<pre>
4894 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4895</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4896
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4897<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4898<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4899 SSA graph representing the function.</p>
4900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4901<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4902<p>The type of the incoming values is specified with the first type field. After
4903 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4904 one pair for each predecessor basic block of the current block. Only values
4905 of <a href="#t_firstclass">first class</a> type may be used as the value
4906 arguments to the PHI node. Only labels may be used as the label
4907 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4908
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4909<p>There must be no non-phi instructions between the start of a basic block and
4910 the PHI instructions: i.e. PHI instructions must be first in a basic
4911 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4912
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4913<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4914 occur on the edge from the corresponding predecessor block to the current
4915 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4916 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4918<h5>Semantics:</h5>
4919<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4920 specified by the pair corresponding to the predecessor basic block that
4921 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4923<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4924<pre>
4925Loop: ; Infinite loop that counts from 0 on up...
4926 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4927 %nextindvar = add i32 %indvar, 1
4928 br label %Loop
4929</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4931</div>
4932
4933<!-- _______________________________________________________________________ -->
4934<div class="doc_subsubsection">
4935 <a name="i_select">'<tt>select</tt>' Instruction</a>
4936</div>
4937
4938<div class="doc_text">
4939
4940<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4941<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4942 &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>
4943
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4944 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4945</pre>
4946
4947<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4948<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4949 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4950
4951
4952<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4953<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4954 values indicating the condition, and two values of the
4955 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4956 vectors and the condition is a scalar, then entire vectors are selected, not
4957 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4958
4959<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4960<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4961 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4962
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4963<p>If the condition is a vector of i1, then the value arguments must be vectors
4964 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4965
4966<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4967<pre>
4968 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4969</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4970
4971<p>Note that the code generator does not yet support conditions
4972 with vector type.</p>
4973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4974</div>
4975
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4976<!-- _______________________________________________________________________ -->
4977<div class="doc_subsubsection">
4978 <a name="i_call">'<tt>call</tt>' Instruction</a>
4979</div>
4980
4981<div class="doc_text">
4982
4983<h5>Syntax:</h5>
4984<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4985 &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]4986</pre>
4987
4988<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4989<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4990
4991<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4992<p>This instruction requires several arguments:</p>
4993
4994<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4995 <li>The optional "tail" marker indicates whether the callee function accesses
4996 any allocas or varargs in the caller. If the "tail" marker is present,
4997 the function call is eligible for tail call optimization. Note that calls
4998 may be marked "tail" even if they do not occur before
4999 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5000
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5001 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5002 convention</a> the call should use. If none is specified, the call
5003 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5004
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5005 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5006 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5007 '<tt>inreg</tt>' attributes are valid here.</li>
5008
5009 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5010 type of the return value. Functions that return no value are marked
5011 <tt><a href="#t_void">void</a></tt>.</li>
5012
5013 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5014 being invoked. The argument types must match the types implied by this
5015 signature. This type can be omitted if the function is not varargs and if
5016 the function type does not return a pointer to a function.</li>
5017
5018 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5019 be invoked. In most cases, this is a direct function invocation, but
5020 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5021 to function value.</li>
5022
5023 <li>'<tt>function args</tt>': argument list whose types match the function
5024 signature argument types. All arguments must be of
5025 <a href="#t_firstclass">first class</a> type. If the function signature
5026 indicates the function accepts a variable number of arguments, the extra
5027 arguments can be specified.</li>
5028
5029 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5030 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5031 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032</ol>
5033
5034<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5035<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5036 a specified function, with its incoming arguments bound to the specified
5037 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5038 function, control flow continues with the instruction after the function
5039 call, and the return value of the function is bound to the result
5040 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5041
5042<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5043<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5044 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5045 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5046 %X = tail call i32 @foo() <i>; yields i32</i>
5047 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5048 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5049
5050 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5051 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5052 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5053 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5054 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5055 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5056</pre>
5057
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5058<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5059standard C99 library as being the C99 library functions, and may perform
5060optimizations or generate code for them under that assumption. This is
5061something we'd like to change in the future to provide better support for
5062freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5064</div>
5065
5066<!-- _______________________________________________________________________ -->
5067<div class="doc_subsubsection">
5068 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5069</div>
5070
5071<div class="doc_text">
5072
5073<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074<pre>
5075 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5076</pre>
5077
5078<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5080 the "variable argument" area of a function call. It is used to implement the
5081 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082
5083<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5084<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5085 argument. It returns a value of the specified argument type and increments
5086 the <tt>va_list</tt> to point to the next argument. The actual type
5087 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088
5089<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5090<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5091 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5092 to the next argument. For more information, see the variable argument
5093 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5094
5095<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]5096 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5097 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5098
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5099<p><tt>va_arg</tt> is an LLVM instruction instead of
5100 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5101 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5102
5103<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5104<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5105
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5106<p>Note that the code generator does not yet fully support va_arg on many
5107 targets. Also, it does not currently support va_arg with aggregate types on
5108 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5110</div>
5111
5112<!-- *********************************************************************** -->
5113<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5114<!-- *********************************************************************** -->
5115
5116<div class="doc_text">
5117
5118<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5119 well known names and semantics and are required to follow certain
5120 restrictions. Overall, these intrinsics represent an extension mechanism for
5121 the LLVM language that does not require changing all of the transformations
5122 in LLVM when adding to the language (or the bitcode reader/writer, the
5123 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5124
5125<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5126 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5127 begin with this prefix. Intrinsic functions must always be external
5128 functions: you cannot define the body of intrinsic functions. Intrinsic
5129 functions may only be used in call or invoke instructions: it is illegal to
5130 take the address of an intrinsic function. Additionally, because intrinsic
5131 functions are part of the LLVM language, it is required if any are added that
5132 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5133
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5134<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5135 family of functions that perform the same operation but on different data
5136 types. Because LLVM can represent over 8 million different integer types,
5137 overloading is used commonly to allow an intrinsic function to operate on any
5138 integer type. One or more of the argument types or the result type can be
5139 overloaded to accept any integer type. Argument types may also be defined as
5140 exactly matching a previous argument's type or the result type. This allows
5141 an intrinsic function which accepts multiple arguments, but needs all of them
5142 to be of the same type, to only be overloaded with respect to a single
5143 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5144
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5145<p>Overloaded intrinsics will have the names of its overloaded argument types
5146 encoded into its function name, each preceded by a period. Only those types
5147 which are overloaded result in a name suffix. Arguments whose type is matched
5148 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5149 can take an integer of any width and returns an integer of exactly the same
5150 integer width. This leads to a family of functions such as
5151 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5152 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5153 suffix is required. Because the argument's type is matched against the return
5154 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5155
5156<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5157 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5158
5159</div>
5160
5161<!-- ======================================================================= -->
5162<div class="doc_subsection">
5163 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5164</div>
5165
5166<div class="doc_text">
5167
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5168<p>Variable argument support is defined in LLVM with
5169 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5170 intrinsic functions. These functions are related to the similarly named
5171 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5172
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5173<p>All of these functions operate on arguments that use a target-specific value
5174 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5175 not define what this type is, so all transformations should be prepared to
5176 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5177
5178<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]5179 instruction and the variable argument handling intrinsic functions are
5180 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5181
5182<div class="doc_code">
5183<pre>
5184define i32 @test(i32 %X, ...) {
5185 ; Initialize variable argument processing
5186 %ap = alloca i8*
5187 %ap2 = bitcast i8** %ap to i8*
5188 call void @llvm.va_start(i8* %ap2)
5189
5190 ; Read a single integer argument
5191 %tmp = va_arg i8** %ap, i32
5192
5193 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5194 %aq = alloca i8*
5195 %aq2 = bitcast i8** %aq to i8*
5196 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5197 call void @llvm.va_end(i8* %aq2)
5198
5199 ; Stop processing of arguments.
5200 call void @llvm.va_end(i8* %ap2)
5201 ret i32 %tmp
5202}
5203
5204declare void @llvm.va_start(i8*)
5205declare void @llvm.va_copy(i8*, i8*)
5206declare void @llvm.va_end(i8*)
5207</pre>
5208</div>
5209
5210</div>
5211
5212<!-- _______________________________________________________________________ -->
5213<div class="doc_subsubsection">
5214 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5215</div>
5216
5217
5218<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5220<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5221<pre>
5222 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5223</pre>
5224
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5225<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5226<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5227 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]5228
5229<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5230<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]5231
5232<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5233<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]5234 macro available in C. In a target-dependent way, it initializes
5235 the <tt>va_list</tt> element to which the argument points, so that the next
5236 call to <tt>va_arg</tt> will produce the first variable argument passed to
5237 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5238 need to know the last argument of the function as the compiler can figure
5239 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240
5241</div>
5242
5243<!-- _______________________________________________________________________ -->
5244<div class="doc_subsubsection">
5245 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5246</div>
5247
5248<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5249
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5250<h5>Syntax:</h5>
5251<pre>
5252 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5253</pre>
5254
5255<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5256<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5257 which has been initialized previously
5258 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5259 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5260
5261<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5262<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5263
5264<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5265<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]5266 macro available in C. In a target-dependent way, it destroys
5267 the <tt>va_list</tt> element to which the argument points. Calls
5268 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5269 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5270 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5271
5272</div>
5273
5274<!-- _______________________________________________________________________ -->
5275<div class="doc_subsubsection">
5276 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5277</div>
5278
5279<div class="doc_text">
5280
5281<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5282<pre>
5283 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5284</pre>
5285
5286<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5287<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5288 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289
5290<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5291<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]5292 The second argument is a pointer to a <tt>va_list</tt> element to copy
5293 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5294
5295<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5296<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]5297 macro available in C. In a target-dependent way, it copies the
5298 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5299 element. This intrinsic is necessary because
5300 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5301 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5302
5303</div>
5304
5305<!-- ======================================================================= -->
5306<div class="doc_subsection">
5307 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5308</div>
5309
5310<div class="doc_text">
5311
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5312<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5313Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5314intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5315roots on the stack</a>, as well as garbage collector implementations that
5316require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5317barriers. Front-ends for type-safe garbage collected languages should generate
5318these intrinsics to make use of the LLVM garbage collectors. For more details,
5319see <a href="GarbageCollection.html">Accurate Garbage Collection with
5320LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5321
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5322<p>The garbage collection intrinsics only operate on objects in the generic
5323 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5325</div>
5326
5327<!-- _______________________________________________________________________ -->
5328<div class="doc_subsubsection">
5329 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5330</div>
5331
5332<div class="doc_text">
5333
5334<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5335<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5336 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5337</pre>
5338
5339<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5340<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]5341 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342
5343<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5344<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5345 root pointer. The second pointer (which must be either a constant or a
5346 global value address) contains the meta-data to be associated with the
5347 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5348
5349<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5350<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]5351 location. At compile-time, the code generator generates information to allow
5352 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5353 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5354 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5355
5356</div>
5357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358<!-- _______________________________________________________________________ -->
5359<div class="doc_subsubsection">
5360 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5361</div>
5362
5363<div class="doc_text">
5364
5365<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5367 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5368</pre>
5369
5370<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5371<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5372 locations, allowing garbage collector implementations that require read
5373 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374
5375<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5376<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]5377 allocated from the garbage collector. The first object is a pointer to the
5378 start of the referenced object, if needed by the language runtime (otherwise
5379 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5380
5381<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5382<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5383 instruction, but may be replaced with substantially more complex code by the
5384 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5385 may only be used in a function which <a href="#gc">specifies a GC
5386 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387
5388</div>
5389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5390<!-- _______________________________________________________________________ -->
5391<div class="doc_subsubsection">
5392 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5393</div>
5394
5395<div class="doc_text">
5396
5397<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5399 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400</pre>
5401
5402<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5404 locations, allowing garbage collector implementations that require write
5405 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406
5407<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5408<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]5409 object to store it to, and the third is the address of the field of Obj to
5410 store to. If the runtime does not require a pointer to the object, Obj may
5411 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5412
5413<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5414<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5415 instruction, but may be replaced with substantially more complex code by the
5416 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5417 may only be used in a function which <a href="#gc">specifies a GC
5418 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5419
5420</div>
5421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5422<!-- ======================================================================= -->
5423<div class="doc_subsection">
5424 <a name="int_codegen">Code Generator Intrinsics</a>
5425</div>
5426
5427<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5428
5429<p>These intrinsics are provided by LLVM to expose special features that may
5430 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5431
5432</div>
5433
5434<!-- _______________________________________________________________________ -->
5435<div class="doc_subsubsection">
5436 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5437</div>
5438
5439<div class="doc_text">
5440
5441<h5>Syntax:</h5>
5442<pre>
5443 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5444</pre>
5445
5446<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5447<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5448 target-specific value indicating the return address of the current function
5449 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450
5451<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5452<p>The argument to this intrinsic indicates which function to return the address
5453 for. Zero indicates the calling function, one indicates its caller, etc.
5454 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455
5456<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5457<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5458 indicating the return address of the specified call frame, or zero if it
5459 cannot be identified. The value returned by this intrinsic is likely to be
5460 incorrect or 0 for arguments other than zero, so it should only be used for
5461 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5462
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5463<p>Note that calling this intrinsic does not prevent function inlining or other
5464 aggressive transformations, so the value returned may not be that of the
5465 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5466
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467</div>
5468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5469<!-- _______________________________________________________________________ -->
5470<div class="doc_subsubsection">
5471 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5472</div>
5473
5474<div class="doc_text">
5475
5476<h5>Syntax:</h5>
5477<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5478 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5479</pre>
5480
5481<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5482<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5483 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484
5485<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5486<p>The argument to this intrinsic indicates which function to return the frame
5487 pointer for. Zero indicates the calling function, one indicates its caller,
5488 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5489
5490<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5491<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5492 indicating the frame address of the specified call frame, or zero if it
5493 cannot be identified. The value returned by this intrinsic is likely to be
5494 incorrect or 0 for arguments other than zero, so it should only be used for
5495 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5496
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5497<p>Note that calling this intrinsic does not prevent function inlining or other
5498 aggressive transformations, so the value returned may not be that of the
5499 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5501</div>
5502
5503<!-- _______________________________________________________________________ -->
5504<div class="doc_subsubsection">
5505 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5506</div>
5507
5508<div class="doc_text">
5509
5510<h5>Syntax:</h5>
5511<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5512 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5513</pre>
5514
5515<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5516<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5517 of the function stack, for use
5518 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5519 useful for implementing language features like scoped automatic variable
5520 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521
5522<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5523<p>This intrinsic returns a opaque pointer value that can be passed
5524 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5525 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5526 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5527 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5528 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5529 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5530
5531</div>
5532
5533<!-- _______________________________________________________________________ -->
5534<div class="doc_subsubsection">
5535 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5536</div>
5537
5538<div class="doc_text">
5539
5540<h5>Syntax:</h5>
5541<pre>
5542 declare void @llvm.stackrestore(i8 * %ptr)
5543</pre>
5544
5545<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5546<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5547 the function stack to the state it was in when the
5548 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5549 executed. This is useful for implementing language features like scoped
5550 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5551
5552<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5553<p>See the description
5554 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5555
5556</div>
5557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5558<!-- _______________________________________________________________________ -->
5559<div class="doc_subsubsection">
5560 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5561</div>
5562
5563<div class="doc_text">
5564
5565<h5>Syntax:</h5>
5566<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5567 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]5568</pre>
5569
5570<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5571<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5572 insert a prefetch instruction if supported; otherwise, it is a noop.
5573 Prefetches have no effect on the behavior of the program but can change its
5574 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5575
5576<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5577<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5578 specifier determining if the fetch should be for a read (0) or write (1),
5579 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5580 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5581 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5582
5583<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5584<p>This intrinsic does not modify the behavior of the program. In particular,
5585 prefetches cannot trap and do not produce a value. On targets that support
5586 this intrinsic, the prefetch can provide hints to the processor cache for
5587 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5588
5589</div>
5590
5591<!-- _______________________________________________________________________ -->
5592<div class="doc_subsubsection">
5593 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5594</div>
5595
5596<div class="doc_text">
5597
5598<h5>Syntax:</h5>
5599<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5600 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5601</pre>
5602
5603<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5604<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5605 Counter (PC) in a region of code to simulators and other tools. The method
5606 is target specific, but it is expected that the marker will use exported
5607 symbols to transmit the PC of the marker. The marker makes no guarantees
5608 that it will remain with any specific instruction after optimizations. It is
5609 possible that the presence of a marker will inhibit optimizations. The
5610 intended use is to be inserted after optimizations to allow correlations of
5611 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5612
5613<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5614<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5615
5616<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5617<p>This intrinsic does not modify the behavior of the program. Backends that do
5618 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5619
5620</div>
5621
5622<!-- _______________________________________________________________________ -->
5623<div class="doc_subsubsection">
5624 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5625</div>
5626
5627<div class="doc_text">
5628
5629<h5>Syntax:</h5>
5630<pre>
5631 declare i64 @llvm.readcyclecounter( )
5632</pre>
5633
5634<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5635<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5636 counter register (or similar low latency, high accuracy clocks) on those
5637 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5638 should map to RPCC. As the backing counters overflow quickly (on the order
5639 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5640
5641<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5642<p>When directly supported, reading the cycle counter should not modify any
5643 memory. Implementations are allowed to either return a application specific
5644 value or a system wide value. On backends without support, this is lowered
5645 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5646
5647</div>
5648
5649<!-- ======================================================================= -->
5650<div class="doc_subsection">
5651 <a name="int_libc">Standard C Library Intrinsics</a>
5652</div>
5653
5654<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5655
5656<p>LLVM provides intrinsics for a few important standard C library functions.
5657 These intrinsics allow source-language front-ends to pass information about
5658 the alignment of the pointer arguments to the code generator, providing
5659 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5660
5661</div>
5662
5663<!-- _______________________________________________________________________ -->
5664<div class="doc_subsubsection">
5665 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5666</div>
5667
5668<div class="doc_text">
5669
5670<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5671<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5672 integer bit width. Not all targets support all bit widths however.</p>
5673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5674<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5675 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5676 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5677 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5678 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5679 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5680 i32 &lt;len&gt;, i32 &lt;align&gt;)
5681 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5682 i64 &lt;len&gt;, i32 &lt;align&gt;)
5683</pre>
5684
5685<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5686<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5687 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5688
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5689<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5690 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5691
5692<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5693<p>The first argument is a pointer to the destination, the second is a pointer
5694 to the source. The third argument is an integer argument specifying the
5695 number of bytes to copy, and the fourth argument is the alignment of the
5696 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5697
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5698<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5699 then the caller guarantees that both the source and destination pointers are
5700 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5701
5702<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5703<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5704 source location to the destination location, which are not allowed to
5705 overlap. It copies "len" bytes of memory over. If the argument is known to
5706 be aligned to some boundary, this can be specified as the fourth argument,
5707 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5708
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709</div>
5710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5711<!-- _______________________________________________________________________ -->
5712<div class="doc_subsubsection">
5713 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5714</div>
5715
5716<div class="doc_text">
5717
5718<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5719<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5720 width. Not all targets support all bit widths however.</p>
5721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5723 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5724 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5725 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5726 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5727 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5728 i32 &lt;len&gt;, i32 &lt;align&gt;)
5729 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5730 i64 &lt;len&gt;, i32 &lt;align&gt;)
5731</pre>
5732
5733<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5734<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5735 source location to the destination location. It is similar to the
5736 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5737 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5739<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5740 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741
5742<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5743<p>The first argument is a pointer to the destination, the second is a pointer
5744 to the source. The third argument is an integer argument specifying the
5745 number of bytes to copy, and the fourth argument is the alignment of the
5746 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5747
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5748<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5749 then the caller guarantees that the source and destination pointers are
5750 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5751
5752<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5753<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5754 source location to the destination location, which may overlap. It copies
5755 "len" bytes of memory over. If the argument is known to be aligned to some
5756 boundary, this can be specified as the fourth argument, otherwise it should
5757 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5759</div>
5760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5761<!-- _______________________________________________________________________ -->
5762<div class="doc_subsubsection">
5763 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5764</div>
5765
5766<div class="doc_text">
5767
5768<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5769<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5770 width. Not all targets support all bit widths however.</p>
5771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5772<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5773 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5774 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5775 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5776 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5778 i32 &lt;len&gt;, i32 &lt;align&gt;)
5779 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5780 i64 &lt;len&gt;, i32 &lt;align&gt;)
5781</pre>
5782
5783<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5784<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5785 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5787<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5788 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789
5790<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5791<p>The first argument is a pointer to the destination to fill, the second is the
5792 byte value to fill it with, the third argument is an integer argument
5793 specifying the number of bytes to fill, and the fourth argument is the known
5794 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5795
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5796<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5797 then the caller guarantees that the destination pointer is aligned to that
5798 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5799
5800<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5801<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5802 at the destination location. If the argument is known to be aligned to some
5803 boundary, this can be specified as the fourth argument, otherwise it should
5804 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806</div>
5807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5808<!-- _______________________________________________________________________ -->
5809<div class="doc_subsubsection">
5810 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5811</div>
5812
5813<div class="doc_text">
5814
5815<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5816<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5817 floating point or vector of floating point type. Not all targets support all
5818 types however.</p>
5819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5820<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5821 declare float @llvm.sqrt.f32(float %Val)
5822 declare double @llvm.sqrt.f64(double %Val)
5823 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5824 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5825 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5826</pre>
5827
5828<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5829<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5830 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5831 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5832 behavior for negative numbers other than -0.0 (which allows for better
5833 optimization, because there is no need to worry about errno being
5834 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]5835
5836<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5837<p>The argument and return value are floating point numbers of the same
5838 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5839
5840<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5841<p>This function returns the sqrt of the specified operand if it is a
5842 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5844</div>
5845
5846<!-- _______________________________________________________________________ -->
5847<div class="doc_subsubsection">
5848 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5849</div>
5850
5851<div class="doc_text">
5852
5853<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5854<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5855 floating point or vector of floating point type. Not all targets support all
5856 types however.</p>
5857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5858<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5859 declare float @llvm.powi.f32(float %Val, i32 %power)
5860 declare double @llvm.powi.f64(double %Val, i32 %power)
5861 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5862 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5863 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5864</pre>
5865
5866<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5867<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5868 specified (positive or negative) power. The order of evaluation of
5869 multiplications is not defined. When a vector of floating point type is
5870 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5871
5872<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5873<p>The second argument is an integer power, and the first is a value to raise to
5874 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5875
5876<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5877<p>This function returns the first value raised to the second power with an
5878 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5880</div>
5881
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5882<!-- _______________________________________________________________________ -->
5883<div class="doc_subsubsection">
5884 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5885</div>
5886
5887<div class="doc_text">
5888
5889<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5890<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5891 floating point or vector of floating point type. Not all targets support all
5892 types however.</p>
5893
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5894<pre>
5895 declare float @llvm.sin.f32(float %Val)
5896 declare double @llvm.sin.f64(double %Val)
5897 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5898 declare fp128 @llvm.sin.f128(fp128 %Val)
5899 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5900</pre>
5901
5902<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5903<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5904
5905<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5906<p>The argument and return value are floating point numbers of the same
5907 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5908
5909<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5910<p>This function returns the sine of the specified operand, returning the same
5911 values as the libm <tt>sin</tt> functions would, and handles error conditions
5912 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5913
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5914</div>
5915
5916<!-- _______________________________________________________________________ -->
5917<div class="doc_subsubsection">
5918 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5919</div>
5920
5921<div class="doc_text">
5922
5923<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5924<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5925 floating point or vector of floating point type. Not all targets support all
5926 types however.</p>
5927
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5928<pre>
5929 declare float @llvm.cos.f32(float %Val)
5930 declare double @llvm.cos.f64(double %Val)
5931 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5932 declare fp128 @llvm.cos.f128(fp128 %Val)
5933 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5934</pre>
5935
5936<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5937<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5938
5939<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5940<p>The argument and return value are floating point numbers of the same
5941 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5942
5943<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5944<p>This function returns the cosine of the specified operand, returning the same
5945 values as the libm <tt>cos</tt> functions would, and handles error conditions
5946 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5947
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5948</div>
5949
5950<!-- _______________________________________________________________________ -->
5951<div class="doc_subsubsection">
5952 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5953</div>
5954
5955<div class="doc_text">
5956
5957<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5958<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5959 floating point or vector of floating point type. Not all targets support all
5960 types however.</p>
5961
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5962<pre>
5963 declare float @llvm.pow.f32(float %Val, float %Power)
5964 declare double @llvm.pow.f64(double %Val, double %Power)
5965 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5966 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5967 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5968</pre>
5969
5970<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5971<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5972 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5973
5974<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5975<p>The second argument is a floating point power, and the first is a value to
5976 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5977
5978<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5979<p>This function returns the first value raised to the second power, returning
5980 the same values as the libm <tt>pow</tt> functions would, and handles error
5981 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5982
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5983</div>
5984
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5985<!-- ======================================================================= -->
5986<div class="doc_subsection">
5987 <a name="int_manip">Bit Manipulation Intrinsics</a>
5988</div>
5989
5990<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5991
5992<p>LLVM provides intrinsics for a few important bit manipulation operations.
5993 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5994
5995</div>
5996
5997<!-- _______________________________________________________________________ -->
5998<div class="doc_subsubsection">
5999 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6000</div>
6001
6002<div class="doc_text">
6003
6004<h5>Syntax:</h5>
6005<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6006 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6007
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6008<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6009 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6010 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6011 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6012</pre>
6013
6014<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6015<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6016 values with an even number of bytes (positive multiple of 16 bits). These
6017 are useful for performing operations on data that is not in the target's
6018 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6019
6020<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6021<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6022 and low byte of the input i16 swapped. Similarly,
6023 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6024 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6025 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6026 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6027 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6028 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6029
6030</div>
6031
6032<!-- _______________________________________________________________________ -->
6033<div class="doc_subsubsection">
6034 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6035</div>
6036
6037<div class="doc_text">
6038
6039<h5>Syntax:</h5>
6040<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]6041 width. Not all targets support all bit widths however.</p>
6042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6043<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6044 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6045 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6046 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6047 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6048 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6049</pre>
6050
6051<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6052<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6053 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6054
6055<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6056<p>The only argument is the value to be counted. The argument may be of any
6057 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6058
6059<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6060<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]6061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6062</div>
6063
6064<!-- _______________________________________________________________________ -->
6065<div class="doc_subsubsection">
6066 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6067</div>
6068
6069<div class="doc_text">
6070
6071<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6072<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6073 integer bit width. Not all targets support all bit widths however.</p>
6074
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6075<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6076 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6077 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6078 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6079 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6080 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081</pre>
6082
6083<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6084<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6085 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6086
6087<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6088<p>The only argument is the value to be counted. The argument may be of any
6089 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6090
6091<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6092<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6093 zeros in a variable. If the src == 0 then the result is the size in bits of
6094 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6095
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6096</div>
6097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6098<!-- _______________________________________________________________________ -->
6099<div class="doc_subsubsection">
6100 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6101</div>
6102
6103<div class="doc_text">
6104
6105<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6106<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6107 integer bit width. Not all targets support all bit widths however.</p>
6108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6109<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6110 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6111 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6112 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6113 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6114 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6115</pre>
6116
6117<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6118<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6119 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6120
6121<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6122<p>The only argument is the value to be counted. The argument may be of any
6123 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6124
6125<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6126<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6127 zeros in a variable. If the src == 0 then the result is the size in bits of
6128 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6130</div>
6131
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6132<!-- ======================================================================= -->
6133<div class="doc_subsection">
6134 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6135</div>
6136
6137<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6138
6139<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6140
6141</div>
6142
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6143<!-- _______________________________________________________________________ -->
6144<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6145 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6146</div>
6147
6148<div class="doc_text">
6149
6150<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6151<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]6152 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6153
6154<pre>
6155 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6156 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6157 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6158</pre>
6159
6160<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6161<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6162 a signed addition of the two arguments, and indicate whether an overflow
6163 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6164
6165<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6166<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]6167 be of integer types of any bit width, but they must have the same bit
6168 width. The second element of the result structure must be of
6169 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6170 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6171
6172<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6173<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6174 a signed addition of the two variables. They return a structure &mdash; the
6175 first element of which is the signed summation, and the second element of
6176 which is a bit specifying if the signed summation resulted in an
6177 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6178
6179<h5>Examples:</h5>
6180<pre>
6181 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6182 %sum = extractvalue {i32, i1} %res, 0
6183 %obit = extractvalue {i32, i1} %res, 1
6184 br i1 %obit, label %overflow, label %normal
6185</pre>
6186
6187</div>
6188
6189<!-- _______________________________________________________________________ -->
6190<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6191 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6192</div>
6193
6194<div class="doc_text">
6195
6196<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6197<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]6198 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6199
6200<pre>
6201 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6202 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6203 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6204</pre>
6205
6206<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6207<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6208 an unsigned addition of the two arguments, and indicate whether a carry
6209 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6210
6211<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6212<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]6213 be of integer types of any bit width, but they must have the same bit
6214 width. The second element of the result structure must be of
6215 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6216 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6217
6218<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6219<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6220 an unsigned addition of the two arguments. They return a structure &mdash;
6221 the first element of which is the sum, and the second element of which is a
6222 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6223
6224<h5>Examples:</h5>
6225<pre>
6226 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6227 %sum = extractvalue {i32, i1} %res, 0
6228 %obit = extractvalue {i32, i1} %res, 1
6229 br i1 %obit, label %carry, label %normal
6230</pre>
6231
6232</div>
6233
6234<!-- _______________________________________________________________________ -->
6235<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6236 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6237</div>
6238
6239<div class="doc_text">
6240
6241<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6242<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]6243 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6244
6245<pre>
6246 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6247 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6248 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6249</pre>
6250
6251<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6252<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6253 a signed subtraction of the two arguments, and indicate whether an overflow
6254 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6255
6256<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6257<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]6258 be of integer types of any bit width, but they must have the same bit
6259 width. The second element of the result structure must be of
6260 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6261 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6262
6263<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6264<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6265 a signed subtraction of the two arguments. They return a structure &mdash;
6266 the first element of which is the subtraction, and the second element of
6267 which is a bit specifying if the signed subtraction resulted in an
6268 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6269
6270<h5>Examples:</h5>
6271<pre>
6272 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6273 %sum = extractvalue {i32, i1} %res, 0
6274 %obit = extractvalue {i32, i1} %res, 1
6275 br i1 %obit, label %overflow, label %normal
6276</pre>
6277
6278</div>
6279
6280<!-- _______________________________________________________________________ -->
6281<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6282 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6283</div>
6284
6285<div class="doc_text">
6286
6287<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6288<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]6289 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6290
6291<pre>
6292 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6293 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6294 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6295</pre>
6296
6297<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6298<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6299 an unsigned subtraction of the two arguments, and indicate whether an
6300 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6301
6302<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6303<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]6304 be of integer types of any bit width, but they must have the same bit
6305 width. The second element of the result structure must be of
6306 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6307 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6308
6309<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6310<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6311 an unsigned subtraction of the two arguments. They return a structure &mdash;
6312 the first element of which is the subtraction, and the second element of
6313 which is a bit specifying if the unsigned subtraction resulted in an
6314 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6315
6316<h5>Examples:</h5>
6317<pre>
6318 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6319 %sum = extractvalue {i32, i1} %res, 0
6320 %obit = extractvalue {i32, i1} %res, 1
6321 br i1 %obit, label %overflow, label %normal
6322</pre>
6323
6324</div>
6325
6326<!-- _______________________________________________________________________ -->
6327<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6328 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6329</div>
6330
6331<div class="doc_text">
6332
6333<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6334<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]6335 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6336
6337<pre>
6338 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6339 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6340 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6341</pre>
6342
6343<h5>Overview:</h5>
6344
6345<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6346 a signed multiplication of the two arguments, and indicate whether an
6347 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6348
6349<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6350<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]6351 be of integer types of any bit width, but they must have the same bit
6352 width. The second element of the result structure must be of
6353 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6354 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6355
6356<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6357<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6358 a signed multiplication of the two arguments. They return a structure &mdash;
6359 the first element of which is the multiplication, and the second element of
6360 which is a bit specifying if the signed multiplication resulted in an
6361 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6362
6363<h5>Examples:</h5>
6364<pre>
6365 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6366 %sum = extractvalue {i32, i1} %res, 0
6367 %obit = extractvalue {i32, i1} %res, 1
6368 br i1 %obit, label %overflow, label %normal
6369</pre>
6370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6371</div>
6372
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6373<!-- _______________________________________________________________________ -->
6374<div class="doc_subsubsection">
6375 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6376</div>
6377
6378<div class="doc_text">
6379
6380<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6381<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]6382 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6383
6384<pre>
6385 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6386 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6387 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6388</pre>
6389
6390<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6391<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6392 a unsigned multiplication of the two arguments, and indicate whether an
6393 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6394
6395<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6396<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]6397 be of integer types of any bit width, but they must have the same bit
6398 width. The second element of the result structure must be of
6399 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6400 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6401
6402<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6403<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6404 an unsigned multiplication of the two arguments. They return a structure
6405 &mdash; the first element of which is the multiplication, and the second
6406 element of which is a bit specifying if the unsigned multiplication resulted
6407 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6408
6409<h5>Examples:</h5>
6410<pre>
6411 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6412 %sum = extractvalue {i32, i1} %res, 0
6413 %obit = extractvalue {i32, i1} %res, 1
6414 br i1 %obit, label %overflow, label %normal
6415</pre>
6416
6417</div>
6418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6419<!-- ======================================================================= -->
6420<div class="doc_subsection">
6421 <a name="int_debugger">Debugger Intrinsics</a>
6422</div>
6423
6424<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6425
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6426<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6427 prefix), are described in
6428 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6429 Level Debugging</a> document.</p>
6430
6431</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6432
6433<!-- ======================================================================= -->
6434<div class="doc_subsection">
6435 <a name="int_eh">Exception Handling Intrinsics</a>
6436</div>
6437
6438<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6439
6440<p>The LLVM exception handling intrinsics (which all start with
6441 <tt>llvm.eh.</tt> prefix), are described in
6442 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6443 Handling</a> document.</p>
6444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6445</div>
6446
6447<!-- ======================================================================= -->
6448<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6449 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6450</div>
6451
6452<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6453
6454<p>This intrinsic makes it possible to excise one parameter, marked with
6455 the <tt>nest</tt> attribute, from a function. The result is a callable
6456 function pointer lacking the nest parameter - the caller does not need to
6457 provide a value for it. Instead, the value to use is stored in advance in a
6458 "trampoline", a block of memory usually allocated on the stack, which also
6459 contains code to splice the nest value into the argument list. This is used
6460 to implement the GCC nested function address extension.</p>
6461
6462<p>For example, if the function is
6463 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6464 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6465 follows:</p>
6466
6467<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6468<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6469 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6470 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6471 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6472 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6473</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6474</div>
6475
6476<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6477 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6478
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6479</div>
6480
6481<!-- _______________________________________________________________________ -->
6482<div class="doc_subsubsection">
6483 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6484</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6485
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6486<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6487
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6488<h5>Syntax:</h5>
6489<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6490 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]6491</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6492
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6493<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6494<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6495 function pointer suitable for executing it.</p>
6496
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6497<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6498<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6499 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6500 sufficiently aligned block of memory; this memory is written to by the
6501 intrinsic. Note that the size and the alignment are target-specific - LLVM
6502 currently provides no portable way of determining them, so a front-end that
6503 generates this intrinsic needs to have some target-specific knowledge.
6504 The <tt>func</tt> argument must hold a function bitcast to
6505 an <tt>i8*</tt>.</p>
6506
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6507<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6508<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6509 dependent code, turning it into a function. A pointer to this function is
6510 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6511 function pointer type</a> before being called. The new function's signature
6512 is the same as that of <tt>func</tt> with any arguments marked with
6513 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6514 is allowed, and it must be of pointer type. Calling the new function is
6515 equivalent to calling <tt>func</tt> with the same argument list, but
6516 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6517 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6518 by <tt>tramp</tt> is modified, then the effect of any later call to the
6519 returned function pointer is undefined.</p>
6520
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6521</div>
6522
6523<!-- ======================================================================= -->
6524<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6525 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6526</div>
6527
6528<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6529
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6530<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6531 hardware constructs for atomic operations and memory synchronization. This
6532 provides an interface to the hardware, not an interface to the programmer. It
6533 is aimed at a low enough level to allow any programming models or APIs
6534 (Application Programming Interfaces) which need atomic behaviors to map
6535 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6536 hardware provides a "universal IR" for source languages, it also provides a
6537 starting point for developing a "universal" atomic operation and
6538 synchronization IR.</p>
6539
6540<p>These do <em>not</em> form an API such as high-level threading libraries,
6541 software transaction memory systems, atomic primitives, and intrinsic
6542 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6543 application libraries. The hardware interface provided by LLVM should allow
6544 a clean implementation of all of these APIs and parallel programming models.
6545 No one model or paradigm should be selected above others unless the hardware
6546 itself ubiquitously does so.</p>
6547
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6548</div>
6549
6550<!-- _______________________________________________________________________ -->
6551<div class="doc_subsubsection">
6552 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6553</div>
6554<div class="doc_text">
6555<h5>Syntax:</h5>
6556<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6557 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]6558</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6559
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6560<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6561<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6562 specific pairs of memory access types.</p>
6563
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6564<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6565<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6566 The first four arguments enables a specific barrier as listed below. The
6567 fith argument specifies that the barrier applies to io or device or uncached
6568 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6569
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6570<ul>
6571 <li><tt>ll</tt>: load-load barrier</li>
6572 <li><tt>ls</tt>: load-store barrier</li>
6573 <li><tt>sl</tt>: store-load barrier</li>
6574 <li><tt>ss</tt>: store-store barrier</li>
6575 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6576</ul>
6577
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6578<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6579<p>This intrinsic causes the system to enforce some ordering constraints upon
6580 the loads and stores of the program. This barrier does not
6581 indicate <em>when</em> any events will occur, it only enforces
6582 an <em>order</em> in which they occur. For any of the specified pairs of load
6583 and store operations (f.ex. load-load, or store-load), all of the first
6584 operations preceding the barrier will complete before any of the second
6585 operations succeeding the barrier begin. Specifically the semantics for each
6586 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6587
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6588<ul>
6589 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6590 after the barrier begins.</li>
6591 <li><tt>ls</tt>: All loads before the barrier must complete before any
6592 store after the barrier begins.</li>
6593 <li><tt>ss</tt>: All stores before the barrier must complete before any
6594 store after the barrier begins.</li>
6595 <li><tt>sl</tt>: All stores before the barrier must complete before any
6596 load after the barrier begins.</li>
6597</ul>
6598
6599<p>These semantics are applied with a logical "and" behavior when more than one
6600 is enabled in a single memory barrier intrinsic.</p>
6601
6602<p>Backends may implement stronger barriers than those requested when they do
6603 not support as fine grained a barrier as requested. Some architectures do
6604 not need all types of barriers and on such architectures, these become
6605 noops.</p>
6606
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6607<h5>Example:</h5>
6608<pre>
6609%ptr = malloc i32
6610 store i32 4, %ptr
6611
6612%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6613 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6614 <i>; guarantee the above finishes</i>
6615 store i32 8, %ptr <i>; before this begins</i>
6616</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6617
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6618</div>
6619
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6620<!-- _______________________________________________________________________ -->
6621<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6622 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6623</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6624
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6625<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6626
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6627<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6628<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6629 any integer bit width and for different address spaces. Not all targets
6630 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6631
6632<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6633 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6634 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6635 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6636 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]6637</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6638
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6639<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6640<p>This loads a value in memory and compares it to a given value. If they are
6641 equal, it stores a new value into the memory.</p>
6642
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6643<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6644<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6645 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6646 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6647 this integer type. While any bit width integer may be used, targets may only
6648 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6649
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6650<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6651<p>This entire intrinsic must be executed atomically. It first loads the value
6652 in memory pointed to by <tt>ptr</tt> and compares it with the
6653 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6654 memory. The loaded value is yielded in all cases. This provides the
6655 equivalent of an atomic compare-and-swap operation within the SSA
6656 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6657
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6658<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6659<pre>
6660%ptr = malloc i32
6661 store i32 4, %ptr
6662
6663%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6664%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6665 <i>; yields {i32}:result1 = 4</i>
6666%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6667%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6668
6669%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6670%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6671 <i>; yields {i32}:result2 = 8</i>
6672%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6673
6674%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6675</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6676
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6677</div>
6678
6679<!-- _______________________________________________________________________ -->
6680<div class="doc_subsubsection">
6681 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6682</div>
6683<div class="doc_text">
6684<h5>Syntax:</h5>
6685
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6686<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6687 integer bit width. Not all targets support all bit widths however.</p>
6688
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6689<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6690 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6691 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6692 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6693 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]6694</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6695
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6696<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6697<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6698 the value from memory. It then stores the value in <tt>val</tt> in the memory
6699 at <tt>ptr</tt>.</p>
6700
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6701<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6702<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6703 the <tt>val</tt> argument and the result must be integers of the same bit
6704 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6705 integer type. The targets may only lower integer representations they
6706 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6707
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6708<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6709<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6710 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6711 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6712
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6713<h5>Examples:</h5>
6714<pre>
6715%ptr = malloc i32
6716 store i32 4, %ptr
6717
6718%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6719%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6720 <i>; yields {i32}:result1 = 4</i>
6721%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6722%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6723
6724%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6725%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6726 <i>; yields {i32}:result2 = 8</i>
6727
6728%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6729%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6730</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6731
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6732</div>
6733
6734<!-- _______________________________________________________________________ -->
6735<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6736 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6737
6738</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6739
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6740<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6741
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6742<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6743<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6744 any integer bit width. Not all targets support all bit widths however.</p>
6745
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6746<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6747 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6748 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6749 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6750 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]6751</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6752
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6753<h5>Overview:</h5>
6754<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6755 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6756
6757<h5>Arguments:</h5>
6758<p>The intrinsic takes two arguments, the first a pointer to an integer value
6759 and the second an integer value. The result is also an integer value. These
6760 integer types can have any bit width, but they must all have the same bit
6761 width. The targets may only lower integer representations they support.</p>
6762
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6763<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6764<p>This intrinsic does a series of operations atomically. It first loads the
6765 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6766 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]6767
6768<h5>Examples:</h5>
6769<pre>
6770%ptr = malloc i32
6771 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6772%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6773 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6774%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6775 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6776%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6777 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6778%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6779</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6780
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6781</div>
6782
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6783<!-- _______________________________________________________________________ -->
6784<div class="doc_subsubsection">
6785 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6786
6787</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6788
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6789<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6790
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6791<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6792<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6793 any integer bit width and for different address spaces. Not all targets
6794 support all bit widths however.</p>
6795
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6796<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6797 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6798 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6799 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6800 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]6801</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6802
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6803<h5>Overview:</h5>
6804<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6805 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6806
6807<h5>Arguments:</h5>
6808<p>The intrinsic takes two arguments, the first a pointer to an integer value
6809 and the second an integer value. The result is also an integer value. These
6810 integer types can have any bit width, but they must all have the same bit
6811 width. The targets may only lower integer representations they support.</p>
6812
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6813<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6814<p>This intrinsic does a series of operations atomically. It first loads the
6815 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6816 result to <tt>ptr</tt>. It yields the original value stored
6817 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6818
6819<h5>Examples:</h5>
6820<pre>
6821%ptr = malloc i32
6822 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6823%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6824 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6825%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6826 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6827%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6828 <i>; yields {i32}:result3 = 2</i>
6829%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6830</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6831
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6832</div>
6833
6834<!-- _______________________________________________________________________ -->
6835<div class="doc_subsubsection">
6836 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6837 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6838 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6839 <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]6840</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6842<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6843
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6844<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6845<p>These are overloaded intrinsics. You can
6846 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6847 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6848 bit width and for different address spaces. Not all targets support all bit
6849 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6850
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6851<pre>
6852 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6853 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6854 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6855 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]6856</pre>
6857
6858<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6859 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6860 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6861 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6862 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]6863</pre>
6864
6865<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6866 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6867 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6868 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6869 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]6870</pre>
6871
6872<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6873 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6874 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6875 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6876 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]6877</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6878
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6879<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6880<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6881 the value stored in memory at <tt>ptr</tt>. It yields the original value
6882 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6883
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6884<h5>Arguments:</h5>
6885<p>These intrinsics take two arguments, the first a pointer to an integer value
6886 and the second an integer value. The result is also an integer value. These
6887 integer types can have any bit width, but they must all have the same bit
6888 width. The targets may only lower integer representations they support.</p>
6889
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6890<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6891<p>These intrinsics does a series of operations atomically. They first load the
6892 value stored at <tt>ptr</tt>. They then do the bitwise
6893 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6894 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6895
6896<h5>Examples:</h5>
6897<pre>
6898%ptr = malloc i32
6899 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6900%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6901 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6902%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6903 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6904%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6905 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6906%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6907 <i>; yields {i32}:result3 = FF</i>
6908%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6909</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6910
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6911</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6912
6913<!-- _______________________________________________________________________ -->
6914<div class="doc_subsubsection">
6915 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6916 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6917 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6918 <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]6919</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6920
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6921<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6922
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6923<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6924<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6925 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6926 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6927 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6929<pre>
6930 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6931 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6932 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6933 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]6934</pre>
6935
6936<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6937 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6938 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6939 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6940 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]6941</pre>
6942
6943<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6944 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6945 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6946 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6947 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]6948</pre>
6949
6950<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6951 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6952 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6953 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6954 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]6955</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6956
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6957<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6958<p>These intrinsics takes the signed or unsigned minimum or maximum of
6959 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6960 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6961
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6962<h5>Arguments:</h5>
6963<p>These intrinsics take two arguments, the first a pointer to an integer value
6964 and the second an integer value. The result is also an integer value. These
6965 integer types can have any bit width, but they must all have the same bit
6966 width. The targets may only lower integer representations they support.</p>
6967
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6968<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6969<p>These intrinsics does a series of operations atomically. They first load the
6970 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6971 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6972 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6973
6974<h5>Examples:</h5>
6975<pre>
6976%ptr = malloc i32
6977 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6978%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6979 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6980%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6981 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6982%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6983 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6984%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6985 <i>; yields {i32}:result3 = 8</i>
6986%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6987</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6988
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6989</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6990
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6991
6992<!-- ======================================================================= -->
6993<div class="doc_subsection">
6994 <a name="int_memorymarkers">Memory Use Markers</a>
6995</div>
6996
6997<div class="doc_text">
6998
6999<p>This class of intrinsics exists to information about the lifetime of memory
7000 objects and ranges where variables are immutable.</p>
7001
7002</div>
7003
7004<!-- _______________________________________________________________________ -->
7005<div class="doc_subsubsection">
7006 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7007</div>
7008
7009<div class="doc_text">
7010
7011<h5>Syntax:</h5>
7012<pre>
7013 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7014</pre>
7015
7016<h5>Overview:</h5>
7017<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7018 object's lifetime.</p>
7019
7020<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame^]7021<p>The first argument is a constant integer representing the size of the
7022 object, or -1 if it is variable sized. The second argument is a pointer to
7023 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7024
7025<h5>Semantics:</h5>
7026<p>This intrinsic indicates that before this point in the code, the value of the
7027 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7028 never be used and has an undefined value. A load from the pointer that is
7029 preceded by this intrinsic can be replaced with
7030 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7031
7032</div>
7033
7034<!-- _______________________________________________________________________ -->
7035<div class="doc_subsubsection">
7036 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7037</div>
7038
7039<div class="doc_text">
7040
7041<h5>Syntax:</h5>
7042<pre>
7043 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7044</pre>
7045
7046<h5>Overview:</h5>
7047<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7048 object's lifetime.</p>
7049
7050<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame^]7051<p>The first argument is a constant integer representing the size of the
7052 object, or -1 if it is variable sized. The second argument is a pointer to
7053 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7054
7055<h5>Semantics:</h5>
7056<p>This intrinsic indicates that after this point in the code, the value of the
7057 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7058 never be used and has an undefined value. Any stores into the memory object
7059 following this intrinsic may be removed as dead.
7060
7061</div>
7062
7063<!-- _______________________________________________________________________ -->
7064<div class="doc_subsubsection">
7065 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7066</div>
7067
7068<div class="doc_text">
7069
7070<h5>Syntax:</h5>
7071<pre>
7072 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7073</pre>
7074
7075<h5>Overview:</h5>
7076<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7077 a memory object will not change.</p>
7078
7079<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame^]7080<p>The first argument is a constant integer representing the size of the
7081 object, or -1 if it is variable sized. The second argument is a pointer to
7082 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7083
7084<h5>Semantics:</h5>
7085<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7086 the return value, the referenced memory location is constant and
7087 unchanging.</p>
7088
7089</div>
7090
7091<!-- _______________________________________________________________________ -->
7092<div class="doc_subsubsection">
7093 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7094</div>
7095
7096<div class="doc_text">
7097
7098<h5>Syntax:</h5>
7099<pre>
7100 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7101</pre>
7102
7103<h5>Overview:</h5>
7104<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7105 a memory object are mutable.</p>
7106
7107<h5>Arguments:</h5>
7108<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame^]7109 The second argument is a constant integer representing the size of the
7110 object, or -1 if it is variable sized and the third argument is a pointer
7111 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7112
7113<h5>Semantics:</h5>
7114<p>This intrinsic indicates that the memory is mutable again.</p>
7115
7116</div>
7117
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7118<!-- ======================================================================= -->
7119<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7120 <a name="int_general">General Intrinsics</a>
7121</div>
7122
7123<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7124
7125<p>This class of intrinsics is designed to be generic and has no specific
7126 purpose.</p>
7127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7128</div>
7129
7130<!-- _______________________________________________________________________ -->
7131<div class="doc_subsubsection">
7132 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7133</div>
7134
7135<div class="doc_text">
7136
7137<h5>Syntax:</h5>
7138<pre>
7139 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7140</pre>
7141
7142<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7143<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7144
7145<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7146<p>The first argument is a pointer to a value, the second is a pointer to a
7147 global string, the third is a pointer to a global string which is the source
7148 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7149
7150<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7151<p>This intrinsic allows annotation of local variables with arbitrary strings.
7152 This can be useful for special purpose optimizations that want to look for
7153 these annotations. These have no other defined use, they are ignored by code
7154 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7156</div>
7157
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7158<!-- _______________________________________________________________________ -->
7159<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7160 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7161</div>
7162
7163<div class="doc_text">
7164
7165<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7166<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7167 any integer bit width.</p>
7168
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7169<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7170 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7171 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7172 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7173 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7174 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]7175</pre>
7176
7177<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7178<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7179
7180<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7181<p>The first argument is an integer value (result of some expression), the
7182 second is a pointer to a global string, the third is a pointer to a global
7183 string which is the source file name, and the last argument is the line
7184 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7185
7186<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7187<p>This intrinsic allows annotations to be put on arbitrary expressions with
7188 arbitrary strings. This can be useful for special purpose optimizations that
7189 want to look for these annotations. These have no other defined use, they
7190 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7191
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7192</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7193
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7194<!-- _______________________________________________________________________ -->
7195<div class="doc_subsubsection">
7196 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7197</div>
7198
7199<div class="doc_text">
7200
7201<h5>Syntax:</h5>
7202<pre>
7203 declare void @llvm.trap()
7204</pre>
7205
7206<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7207<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7208
7209<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7210<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7211
7212<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7213<p>This intrinsics is lowered to the target dependent trap instruction. If the
7214 target does not have a trap instruction, this intrinsic will be lowered to
7215 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7216
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7217</div>
7218
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7219<!-- _______________________________________________________________________ -->
7220<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7221 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7222</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7223
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7224<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7225
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7226<h5>Syntax:</h5>
7227<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7228 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7229</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7230
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7231<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7232<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7233 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7234 ensure that it is placed on the stack before local variables.</p>
7235
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7236<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7237<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7238 arguments. The first argument is the value loaded from the stack
7239 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7240 that has enough space to hold the value of the guard.</p>
7241
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7242<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7243<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7244 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7245 stack. This is to ensure that if a local variable on the stack is
7246 overwritten, it will destroy the value of the guard. When the function exits,
7247 the guard on the stack is checked against the original guard. If they're
7248 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7249 function.</p>
7250
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7251</div>
7252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7253<!-- *********************************************************************** -->
7254<hr>
7255<address>
7256 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7257 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7258 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7259 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7260
7261 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7262 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7263 Last modified: $Date$
7264</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7266</body>
7267</html>