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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 3d72cd8e173b1424d6e41eae1494268e457dc718 / . / docs / LangRef.html
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4<head>
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.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
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>
34 <li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
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>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]59 <li><a href="#t_floating">Floating Point Types</a></li>
60 <li><a href="#t_void">Void Type</a></li>
61 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]62 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]63 </ol>
64 </li>
65 <li><a href="#t_derived">Derived Types</a>
66 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]67 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]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>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]276 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]277 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]278 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]279 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]280 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]281 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]282 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]283 '<tt>llvm.trap</tt>' Intrinsic</a></li>
284 <li><a href="#int_stackprotector">
285 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]286 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]287 </li>
288 </ol>
289 </li>
290</ol>
291
292<div class="doc_author">
293 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
294 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
295</div>
296
297<!-- *********************************************************************** -->
298<div class="doc_section"> <a name="abstract">Abstract </a></div>
299<!-- *********************************************************************** -->
300
301<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]302
303<p>This document is a reference manual for the LLVM assembly language. LLVM is
304 a Static Single Assignment (SSA) based representation that provides type
305 safety, low-level operations, flexibility, and the capability of representing
306 'all' high-level languages cleanly. It is the common code representation
307 used throughout all phases of the LLVM compilation strategy.</p>
308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]309</div>
310
311<!-- *********************************************************************** -->
312<div class="doc_section"> <a name="introduction">Introduction</a> </div>
313<!-- *********************************************************************** -->
314
315<div class="doc_text">
316
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]317<p>The LLVM code representation is designed to be used in three different forms:
318 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
319 for fast loading by a Just-In-Time compiler), and as a human readable
320 assembly language representation. This allows LLVM to provide a powerful
321 intermediate representation for efficient compiler transformations and
322 analysis, while providing a natural means to debug and visualize the
323 transformations. The three different forms of LLVM are all equivalent. This
324 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]325
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]326<p>The LLVM representation aims to be light-weight and low-level while being
327 expressive, typed, and extensible at the same time. It aims to be a
328 "universal IR" of sorts, by being at a low enough level that high-level ideas
329 may be cleanly mapped to it (similar to how microprocessors are "universal
330 IR's", allowing many source languages to be mapped to them). By providing
331 type information, LLVM can be used as the target of optimizations: for
332 example, through pointer analysis, it can be proven that a C automatic
333 variable is never accessed outside of the current function... allowing it to
334 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]335
336</div>
337
338<!-- _______________________________________________________________________ -->
339<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
340
341<div class="doc_text">
342
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]343<p>It is important to note that this document describes 'well formed' LLVM
344 assembly language. There is a difference between what the parser accepts and
345 what is considered 'well formed'. For example, the following instruction is
346 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348<div class="doc_code">
349<pre>
350%x = <a href="#i_add">add</a> i32 1, %x
351</pre>
352</div>
353
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]354<p>...because the definition of <tt>%x</tt> does not dominate all of its
355 uses. The LLVM infrastructure provides a verification pass that may be used
356 to verify that an LLVM module is well formed. This pass is automatically run
357 by the parser after parsing input assembly and by the optimizer before it
358 outputs bitcode. The violations pointed out by the verifier pass indicate
359 bugs in transformation passes or input to the parser.</p>
360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]361</div>
362
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]363<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]364
365<!-- *********************************************************************** -->
366<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
367<!-- *********************************************************************** -->
368
369<div class="doc_text">
370
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]371<p>LLVM identifiers come in two basic types: global and local. Global
372 identifiers (functions, global variables) begin with the <tt>'@'</tt>
373 character. Local identifiers (register names, types) begin with
374 the <tt>'%'</tt> character. Additionally, there are three different formats
375 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]376
377<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]378 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]379 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
380 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
381 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
382 other characters in their names can be surrounded with quotes. Special
383 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
384 ASCII code for the character in hexadecimal. In this way, any character
385 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]386
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]387 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]388 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]389
390 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]391 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]392</ol>
393
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]394<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]395 don't need to worry about name clashes with reserved words, and the set of
396 reserved words may be expanded in the future without penalty. Additionally,
397 unnamed identifiers allow a compiler to quickly come up with a temporary
398 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399
400<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]401 languages. There are keywords for different opcodes
402 ('<tt><a href="#i_add">add</a></tt>',
403 '<tt><a href="#i_bitcast">bitcast</a></tt>',
404 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
405 ('<tt><a href="#t_void">void</a></tt>',
406 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
407 reserved words cannot conflict with variable names, because none of them
408 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409
410<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]412
413<p>The easy way:</p>
414
415<div class="doc_code">
416<pre>
417%result = <a href="#i_mul">mul</a> i32 %X, 8
418</pre>
419</div>
420
421<p>After strength reduction:</p>
422
423<div class="doc_code">
424<pre>
425%result = <a href="#i_shl">shl</a> i32 %X, i8 3
426</pre>
427</div>
428
429<p>And the hard way:</p>
430
431<div class="doc_code">
432<pre>
433<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
434<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
435%result = <a href="#i_add">add</a> i32 %1, %1
436</pre>
437</div>
438
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]439<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
440 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]441
442<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]443 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]444 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]445
446 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]447 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]448
449 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]450</ol>
451
452<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]453 demonstrating instructions, we will follow an instruction with a comment that
454 defines the type and name of value produced. Comments are shown in italic
455 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456
457</div>
458
459<!-- *********************************************************************** -->
460<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
461<!-- *********************************************************************** -->
462
463<!-- ======================================================================= -->
464<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
465</div>
466
467<div class="doc_text">
468
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]469<p>LLVM programs are composed of "Module"s, each of which is a translation unit
470 of the input programs. Each module consists of functions, global variables,
471 and symbol table entries. Modules may be combined together with the LLVM
472 linker, which merges function (and global variable) definitions, resolves
473 forward declarations, and merges symbol table entries. Here is an example of
474 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]475
476<div class="doc_code">
477<pre><i>; Declare the string constant as a global constant...</i>
478<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
479 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
480
481<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]482<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]483
484<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]485define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]486 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]487 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]488 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]489
490 <i>; Call puts function to write out the string to stdout...</i>
491 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]492 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]493 <a
494 href="#i_ret">ret</a> i32 0<br>}<br>
495</pre>
496</div>
497
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]498<p>This example is made up of a <a href="#globalvars">global variable</a> named
499 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
500 a <a href="#functionstructure">function definition</a> for
501 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]503<p>In general, a module is made up of a list of global values, where both
504 functions and global variables are global values. Global values are
505 represented by a pointer to a memory location (in this case, a pointer to an
506 array of char, and a pointer to a function), and have one of the
507 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]508
509</div>
510
511<!-- ======================================================================= -->
512<div class="doc_subsection">
513 <a name="linkage">Linkage Types</a>
514</div>
515
516<div class="doc_text">
517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]518<p>All Global Variables and Functions have one of the following types of
519 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]520
521<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]522 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]523 <dd>Global values with private linkage are only directly accessible by objects
524 in the current module. In particular, linking code into a module with an
525 private global value may cause the private to be renamed as necessary to
526 avoid collisions. Because the symbol is private to the module, all
527 references can be updated. This doesn't show up in any symbol table in the
528 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]529
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]531 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]532 removed by the linker after evaluation. Note that (unlike private
533 symbols) linker_private symbols are subject to coalescing by the linker:
534 weak symbols get merged and redefinitions are rejected. However, unlike
535 normal strong symbols, they are removed by the linker from the final
536 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]537
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]539 <dd>Similar to private, but the value shows as a local symbol
540 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
541 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]544 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]545 into the object file corresponding to the LLVM module. They exist to
546 allow inlining and other optimizations to take place given knowledge of
547 the definition of the global, which is known to be somewhere outside the
548 module. Globals with <tt>available_externally</tt> linkage are allowed to
549 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
550 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]552 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]553 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]554 the same name when linkage occurs. This is typically used to implement
555 inline functions, templates, or other code which must be generated in each
556 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
557 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558
559 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]560 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
561 <tt>linkonce</tt> linkage, except that unreferenced globals with
562 <tt>weak</tt> linkage may not be discarded. This is used for globals that
563 are declared "weak" in C source code.</dd>
564
565 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
566 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
567 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
568 global scope.
569 Symbols with "<tt>common</tt>" linkage are merged in the same way as
570 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]571 <tt>common</tt> symbols may not have an explicit section,
572 must have a zero initializer, and may not be marked '<a
573 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
574 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]576
577 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]579 pointer to array type. When two global variables with appending linkage
580 are linked together, the two global arrays are appended together. This is
581 the LLVM, typesafe, equivalent of having the system linker append together
582 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583
584 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]585 <dd>The semantics of this linkage follow the ELF object file model: the symbol
586 is weak until linked, if not linked, the symbol becomes null instead of
587 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]591 <dd>Some languages allow differing globals to be merged, such as two functions
592 with different semantics. Other languages, such as <tt>C++</tt>, ensure
593 that only equivalent globals are ever merged (the "one definition rule" -
594 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
595 and <tt>weak_odr</tt> linkage types to indicate that the global will only
596 be merged with equivalent globals. These linkage types are otherwise the
597 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]599 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]600 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]601 visible, meaning that it participates in linkage and can be used to
602 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603</dl>
604
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]605<p>The next two types of linkage are targeted for Microsoft Windows platform
606 only. They are designed to support importing (exporting) symbols from (to)
607 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]609<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]610 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]611 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]612 or variable via a global pointer to a pointer that is set up by the DLL
613 exporting the symbol. On Microsoft Windows targets, the pointer name is
614 formed by combining <code>__imp_</code> and the function or variable
615 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616
617 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]618 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]619 pointer to a pointer in a DLL, so that it can be referenced with the
620 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
621 name is formed by combining <code>__imp_</code> and the function or
622 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623</dl>
624
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]625<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
626 another module defined a "<tt>.LC0</tt>" variable and was linked with this
627 one, one of the two would be renamed, preventing a collision. Since
628 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
629 declarations), they are accessible outside of the current module.</p>
630
631<p>It is illegal for a function <i>declaration</i> to have any linkage type
632 other than "externally visible", <tt>dllimport</tt>
633 or <tt>extern_weak</tt>.</p>
634
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]635<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]636 or <tt>weak_odr</tt> linkages.</p>
637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]638</div>
639
640<!-- ======================================================================= -->
641<div class="doc_subsection">
642 <a name="callingconv">Calling Conventions</a>
643</div>
644
645<div class="doc_text">
646
647<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]648 and <a href="#i_invoke">invokes</a> can all have an optional calling
649 convention specified for the call. The calling convention of any pair of
650 dynamic caller/callee must match, or the behavior of the program is
651 undefined. The following calling conventions are supported by LLVM, and more
652 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]653
654<dl>
655 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]656 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]657 specified) matches the target C calling conventions. This calling
658 convention supports varargs function calls and tolerates some mismatch in
659 the declared prototype and implemented declaration of the function (as
660 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]661
662 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]664 (e.g. by passing things in registers). This calling convention allows the
665 target to use whatever tricks it wants to produce fast code for the
666 target, without having to conform to an externally specified ABI
667 (Application Binary Interface). Implementations of this convention should
668 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
669 optimization</a> to be supported. This calling convention does not
670 support varargs and requires the prototype of all callees to exactly match
671 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]672
673 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]674 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]675 as possible under the assumption that the call is not commonly executed.
676 As such, these calls often preserve all registers so that the call does
677 not break any live ranges in the caller side. This calling convention
678 does not support varargs and requires the prototype of all callees to
679 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]680
681 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]682 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]683 target-specific calling conventions to be used. Target specific calling
684 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]685</dl>
686
687<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]688 support Pascal conventions or any other well-known target-independent
689 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]690
691</div>
692
693<!-- ======================================================================= -->
694<div class="doc_subsection">
695 <a name="visibility">Visibility Styles</a>
696</div>
697
698<div class="doc_text">
699
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]700<p>All Global Variables and Functions have one of the following visibility
701 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702
703<dl>
704 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]705 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]706 that the declaration is visible to other modules and, in shared libraries,
707 means that the declared entity may be overridden. On Darwin, default
708 visibility means that the declaration is visible to other modules. Default
709 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710
711 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]712 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol
715 table, so no other module (executable or shared library) can reference it
716 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717
718 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]719 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]720 the dynamic symbol table, but that references within the defining module
721 will bind to the local symbol. That is, the symbol cannot be overridden by
722 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<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]735 it easier to read the IR and make the IR more condensed (particularly when
736 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]744<p>You may give a name to any <a href="#typesystem">type</a> except
745 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
746 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]747
748<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]749 and that you can therefore specify multiple names for the same type. This
750 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
751 uses structural typing, the name is not part of the type. When printing out
752 LLVM IR, the printer will pick <em>one name</em> to render all types of a
753 particular shape. This means that if you have code where two different
754 source types end up having the same LLVM type, that the dumper will sometimes
755 print the "wrong" or unexpected type. This is an important design point and
756 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]757
758</div>
759
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
767<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]768 instead of run-time. Global variables may optionally be initialized, may
769 have an explicit section to be placed in, and may have an optional explicit
770 alignment specified. A variable may be defined as "thread_local", which
771 means that it will not be shared by threads (each thread will have a
772 separated copy of the variable). A variable may be defined as a global
773 "constant," which indicates that the contents of the variable
774 will <b>never</b> be modified (enabling better optimization, allowing the
775 global data to be placed in the read-only section of an executable, etc).
776 Note that variables that need runtime initialization cannot be marked
777 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]778
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]779<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
780 constant, even if the final definition of the global is not. This capability
781 can be used to enable slightly better optimization of the program, but
782 requires the language definition to guarantee that optimizations based on the
783 'constantness' are valid for the translation units that do not include the
784 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]786<p>As SSA values, global variables define pointer values that are in scope
787 (i.e. they dominate) all basic blocks in the program. Global variables
788 always define a pointer to their "content" type because they describe a
789 region of memory, and all memory objects in LLVM are accessed through
790 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]792<p>A global variable may be declared to reside in a target-specific numbered
793 address space. For targets that support them, address spaces may affect how
794 optimizations are performed and/or what target instructions are used to
795 access the variable. The default address space is zero. The address space
796 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]798<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]799 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800
801<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]802 the alignment is set to zero, the alignment of the global is set by the
803 target to whatever it feels convenient. If an explicit alignment is
804 specified, the global is forced to have at least that much alignment. All
805 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]806
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]807<p>For example, the following defines a global in a numbered address space with
808 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]809
810<div class="doc_code">
811<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]812@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813</pre>
814</div>
815
816</div>
817
818
819<!-- ======================================================================= -->
820<div class="doc_subsection">
821 <a name="functionstructure">Functions</a>
822</div>
823
824<div class="doc_text">
825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]826<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
827 optional <a href="#linkage">linkage type</a>, an optional
828 <a href="#visibility">visibility style</a>, an optional
829 <a href="#callingconv">calling convention</a>, a return type, an optional
830 <a href="#paramattrs">parameter attribute</a> for the return type, a function
831 name, a (possibly empty) argument list (each with optional
832 <a href="#paramattrs">parameter attributes</a>), optional
833 <a href="#fnattrs">function attributes</a>, an optional section, an optional
834 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
835 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]836
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]837<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
838 optional <a href="#linkage">linkage type</a>, an optional
839 <a href="#visibility">visibility style</a>, an optional
840 <a href="#callingconv">calling convention</a>, a return type, an optional
841 <a href="#paramattrs">parameter attribute</a> for the return type, a function
842 name, a possibly empty list of arguments, an optional alignment, and an
843 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]844
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]845<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]846 (Control Flow Graph) for the function. Each basic block may optionally start
847 with a label (giving the basic block a symbol table entry), contains a list
848 of instructions, and ends with a <a href="#terminators">terminator</a>
849 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850
851<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]852 executed on entrance to the function, and it is not allowed to have
853 predecessor basic blocks (i.e. there can not be any branches to the entry
854 block of a function). Because the block can have no predecessors, it also
855 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
857<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]858 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]859
860<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]861 the alignment is set to zero, the alignment of the function is set by the
862 target to whatever it feels convenient. If an explicit alignment is
863 specified, the function is forced to have at least that much alignment. All
864 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]865
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]866<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]867<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]868<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]869define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]870 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
871 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
872 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
873 [<a href="#gc">gc</a>] { ... }
874</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]875</div>
876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]877</div>
878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]879<!-- ======================================================================= -->
880<div class="doc_subsection">
881 <a name="aliasstructure">Aliases</a>
882</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]885
886<p>Aliases act as "second name" for the aliasee value (which can be either
887 function, global variable, another alias or bitcast of global value). Aliases
888 may have an optional <a href="#linkage">linkage type</a>, and an
889 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]891<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892<div class="doc_code">
893<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]894@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895</pre>
896</div>
897
898</div>
899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900<!-- ======================================================================= -->
901<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]903<div class="doc_text">
904
905<p>The return type and each parameter of a function type may have a set of
906 <i>parameter attributes</i> associated with them. Parameter attributes are
907 used to communicate additional information about the result or parameters of
908 a function. Parameter attributes are considered to be part of the function,
909 not of the function type, so functions with different parameter attributes
910 can have the same function type.</p>
911
912<p>Parameter attributes are simple keywords that follow the type specified. If
913 multiple parameter attributes are needed, they are space separated. For
914 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915
916<div class="doc_code">
917<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]918declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]919declare i32 @atoi(i8 zeroext)
920declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]921</pre>
922</div>
923
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]924<p>Note that any attributes for the function result (<tt>nounwind</tt>,
925 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]926
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]927<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]929<dl>
930 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931 <dd>This indicates to the code generator that the parameter or return value
932 should be zero-extended to a 32-bit value by the caller (for a parameter)
933 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]935 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be sign-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]940 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates that this parameter or return value should be treated in a
942 special target-dependent fashion during while emitting code for a function
943 call or return (usually, by putting it in a register as opposed to memory,
944 though some targets use it to distinguish between two different kinds of
945 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]947 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that the pointer parameter should really be passed by value
949 to the function. The attribute implies that a hidden copy of the pointee
950 is made between the caller and the callee, so the callee is unable to
951 modify the value in the callee. This attribute is only valid on LLVM
952 pointer arguments. It is generally used to pass structs and arrays by
953 value, but is also valid on pointers to scalars. The copy is considered
954 to belong to the caller not the callee (for example,
955 <tt><a href="#readonly">readonly</a></tt> functions should not write to
956 <tt>byval</tt> parameters). This is not a valid attribute for return
957 values. The byval attribute also supports specifying an alignment with
958 the align attribute. This has a target-specific effect on the code
959 generator that usually indicates a desired alignment for the synthesized
960 stack slot.</dd>
961
962 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]963 <dd>This indicates that the pointer parameter specifies the address of a
964 structure that is the return value of the function in the source program.
965 This pointer must be guaranteed by the caller to be valid: loads and
966 stores to the structure may be assumed by the callee to not to trap. This
967 may only be applied to the first parameter. This is not a valid attribute
968 for return values. </dd>
969
970 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]971 <dd>This indicates that the pointer does not alias any global or any other
972 parameter. The caller is responsible for ensuring that this is the
973 case. On a function return value, <tt>noalias</tt> additionally indicates
974 that the pointer does not alias any other pointers visible to the
975 caller. For further details, please see the discussion of the NoAlias
976 response in
977 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
978 analysis</a>.</dd>
979
980 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]981 <dd>This indicates that the callee does not make any copies of the pointer
982 that outlive the callee itself. This is not a valid attribute for return
983 values.</dd>
984
985 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the pointer parameter can be excised using the
987 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
988 attribute for return values.</dd>
989</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]990
991</div>
992
993<!-- ======================================================================= -->
994<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]995 <a name="gc">Garbage Collector Names</a>
996</div>
997
998<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]999
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1000<p>Each function may specify a garbage collector name, which is simply a
1001 string:</p>
1002
1003<div class="doc_code">
1004<pre>
1005define void @f() gc "name" { ...
1006</pre>
1007</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1008
1009<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1010 collector which will cause the compiler to alter its output in order to
1011 support the named garbage collection algorithm.</p>
1012
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1013</div>
1014
1015<!-- ======================================================================= -->
1016<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1017 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1018</div>
1019
1020<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1021
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1022<p>Function attributes are set to communicate additional information about a
1023 function. Function attributes are considered to be part of the function, not
1024 of the function type, so functions with different parameter attributes can
1025 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are simple keywords that follow the type specified. If
1028 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1029
1030<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1031<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1032define void @f() noinline { ... }
1033define void @f() alwaysinline { ... }
1034define void @f() alwaysinline optsize { ... }
1035define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1036</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1037</div>
1038
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1039<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1040 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1041 <dd>This attribute indicates that the inliner should attempt to inline this
1042 function into callers whenever possible, ignoring any active inlining size
1043 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1044
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1045 <dt><tt>inlinehint</tt></dt>
1046 <dd>This attribute indicates that the source code contained a hint that inlining
1047 this function is desirable (such as the "inline" keyword in C/C++). It
1048 is just a hint; it imposes no requirements on the inliner.</dd>
1049
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1050 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1051 <dd>This attribute indicates that the inliner should never inline this
1052 function in any situation. This attribute may not be used together with
1053 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1054
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1055 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute suggests that optimization passes and code generator passes
1057 make choices that keep the code size of this function low, and otherwise
1058 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1060 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This function attribute indicates that the function never returns
1062 normally. This produces undefined behavior at runtime if the function
1063 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1064
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1065 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns with an
1067 unwind or exceptional control flow. If the function does unwind, its
1068 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1069
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1070 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This attribute indicates that the function computes its result (or decides
1072 to unwind an exception) based strictly on its arguments, without
1073 dereferencing any pointer arguments or otherwise accessing any mutable
1074 state (e.g. memory, control registers, etc) visible to caller functions.
1075 It does not write through any pointer arguments
1076 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1077 changes any state visible to callers. This means that it cannot unwind
1078 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1079 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1080
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1081 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the function does not write through any
1083 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1084 arguments) or otherwise modify any state (e.g. memory, control registers,
1085 etc) visible to caller functions. It may dereference pointer arguments
1086 and read state that may be set in the caller. A readonly function always
1087 returns the same value (or unwinds an exception identically) when called
1088 with the same set of arguments and global state. It cannot unwind an
1089 exception by calling the <tt>C++</tt> exception throwing methods, but may
1090 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1091
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1092 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1093 <dd>This attribute indicates that the function should emit a stack smashing
1094 protector. It is in the form of a "canary"&mdash;a random value placed on
1095 the stack before the local variables that's checked upon return from the
1096 function to see if it has been overwritten. A heuristic is used to
1097 determine if a function needs stack protectors or not.<br>
1098<br>
1099 If a function that has an <tt>ssp</tt> attribute is inlined into a
1100 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1101 function will have an <tt>ssp</tt> attribute.</dd>
1102
1103 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attribute indicates that the function should <em>always</em> emit a
1105 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1106 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1107<br>
1108 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1109 function that doesn't have an <tt>sspreq</tt> attribute or which has
1110 an <tt>ssp</tt> attribute, then the resulting function will have
1111 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1112
1113 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1114 <dd>This attribute indicates that the code generator should not use a red
1115 zone, even if the target-specific ABI normally permits it.</dd>
1116
1117 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1118 <dd>This attributes disables implicit floating point instructions.</dd>
1119
1120 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute disables prologue / epilogue emission for the function.
1122 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1123</dl>
1124
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1125</div>
1126
1127<!-- ======================================================================= -->
1128<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1129 <a name="moduleasm">Module-Level Inline Assembly</a>
1130</div>
1131
1132<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1133
1134<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1135 the GCC "file scope inline asm" blocks. These blocks are internally
1136 concatenated by LLVM and treated as a single unit, but may be separated in
1137 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1138
1139<div class="doc_code">
1140<pre>
1141module asm "inline asm code goes here"
1142module asm "more can go here"
1143</pre>
1144</div>
1145
1146<p>The strings can contain any character by escaping non-printable characters.
1147 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]1148 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1149
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1150<p>The inline asm code is simply printed to the machine code .s file when
1151 assembly code is generated.</p>
1152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1153</div>
1154
1155<!-- ======================================================================= -->
1156<div class="doc_subsection">
1157 <a name="datalayout">Data Layout</a>
1158</div>
1159
1160<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1162<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1163 data is to be laid out in memory. The syntax for the data layout is
1164 simply:</p>
1165
1166<div class="doc_code">
1167<pre>
1168target datalayout = "<i>layout specification</i>"
1169</pre>
1170</div>
1171
1172<p>The <i>layout specification</i> consists of a list of specifications
1173 separated by the minus sign character ('-'). Each specification starts with
1174 a letter and may include other information after the letter to define some
1175 aspect of the data layout. The specifications accepted are as follows:</p>
1176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1177<dl>
1178 <dt><tt>E</tt></dt>
1179 <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]1180 bits with the most significance have the lowest address location.</dd>
1181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1182 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1183 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1184 the bits with the least significance have the lowest address
1185 location.</dd>
1186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1187 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <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]1189 <i>preferred</i> alignments. All sizes are in bits. Specifying
1190 the <i>pref</i> alignment is optional. If omitted, the
1191 preceding <tt>:</tt> should be omitted too.</dd>
1192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1193 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1194 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1195 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1197 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1198 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1199 <i>size</i>.</dd>
1200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1201 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1202 <dd>This specifies the alignment for a floating point 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 either 32 (float) or 64
1204 (double).</dd>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>.</dd>
1209
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1210 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1211 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1212 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1213</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1216 default set of specifications which are then (possibly) overriden by the
1217 specifications in the <tt>datalayout</tt> keyword. The default specifications
1218 are given in this list:</p>
1219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1220<ul>
1221 <li><tt>E</tt> - big endian</li>
1222 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1223 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1224 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1225 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1226 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1227 <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]1228 alignment of 64-bits</li>
1229 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1230 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1231 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1232 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1233 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1234 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1235</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1236
1237<p>When LLVM is determining the alignment for a given type, it uses the
1238 following rules:</p>
1239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1240<ol>
1241 <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]1242 specification is used.</li>
1243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1244 <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]1245 smallest integer type that is larger than the bitwidth of the sought type
1246 is used. If none of the specifications are larger than the bitwidth then
1247 the the largest integer type is used. For example, given the default
1248 specifications above, the i7 type will use the alignment of i8 (next
1249 largest) while both i65 and i256 will use the alignment of i64 (largest
1250 specified).</li>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252 <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]1253 largest vector type that is smaller than the sought vector type will be
1254 used as a fall back. This happens because &lt;128 x double&gt; can be
1255 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258</div>
1259
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1260<!-- ======================================================================= -->
1261<div class="doc_subsection">
1262 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1263</div>
1264
1265<div class="doc_text">
1266
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1267<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1268with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1269is undefined. Pointer values are associated with address ranges
1270according to the following rules:</p>
1271
1272<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1273 <li>A pointer value formed from a
1274 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1275 is associated with the addresses associated with the first operand
1276 of the <tt>getelementptr</tt>.</li>
1277 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1278 range of the variable's storage.</li>
1279 <li>The result value of an allocation instruction is associated with
1280 the address range of the allocated storage.</li>
1281 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1282 no address.</li>
1283 <li>A pointer value formed by an
1284 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1285 address ranges of all pointer values that contribute (directly or
1286 indirectly) to the computation of the pointer's value.</li>
1287 <li>The result value of a
1288 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1289 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1290 <li>An integer constant other than zero or a pointer value returned
1291 from a function not defined within LLVM may be associated with address
1292 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1293 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1294 allocated by mechanisms provided by LLVM.</li>
1295 </ul>
1296
1297<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1298<tt><a href="#i_load">load</a></tt> merely indicates the size and
1299alignment of the memory from which to load, as well as the
1300interpretation of the value. The first operand of a
1301<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1302and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1303
1304<p>Consequently, type-based alias analysis, aka TBAA, aka
1305<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1306LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1307additional information which specialized optimization passes may use
1308to implement type-based alias analysis.</p>
1309
1310</div>
1311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1312<!-- *********************************************************************** -->
1313<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1314<!-- *********************************************************************** -->
1315
1316<div class="doc_text">
1317
1318<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1319 intermediate representation. Being typed enables a number of optimizations
1320 to be performed on the intermediate representation directly, without having
1321 to do extra analyses on the side before the transformation. A strong type
1322 system makes it easier to read the generated code and enables novel analyses
1323 and transformations that are not feasible to perform on normal three address
1324 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1325
1326</div>
1327
1328<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1329<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1330Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1332<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1333
1334<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1335
1336<table border="1" cellspacing="0" cellpadding="4">
1337 <tbody>
1338 <tr><th>Classification</th><th>Types</th></tr>
1339 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1340 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1341 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1342 </tr>
1343 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1344 <td><a href="#t_floating">floating point</a></td>
1345 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346 </tr>
1347 <tr>
1348 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1349 <td><a href="#t_integer">integer</a>,
1350 <a href="#t_floating">floating point</a>,
1351 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1352 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1353 <a href="#t_struct">structure</a>,
1354 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1355 <a href="#t_label">label</a>,
1356 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1357 </td>
1358 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1359 <tr>
1360 <td><a href="#t_primitive">primitive</a></td>
1361 <td><a href="#t_label">label</a>,
1362 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1363 <a href="#t_floating">floating point</a>,
1364 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1365 </tr>
1366 <tr>
1367 <td><a href="#t_derived">derived</a></td>
1368 <td><a href="#t_integer">integer</a>,
1369 <a href="#t_array">array</a>,
1370 <a href="#t_function">function</a>,
1371 <a href="#t_pointer">pointer</a>,
1372 <a href="#t_struct">structure</a>,
1373 <a href="#t_pstruct">packed structure</a>,
1374 <a href="#t_vector">vector</a>,
1375 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1376 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378 </tbody>
1379</table>
1380
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1381<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1382 important. Values of these types are the only ones which can be produced by
1383 instructions, passed as arguments, or used as operands to instructions.</p>
1384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1385</div>
1386
1387<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1388<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1389
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1390<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1391
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1392<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1393 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1394
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1395</div>
1396
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1397<!-- _______________________________________________________________________ -->
1398<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1399
1400<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1401
1402<table>
1403 <tbody>
1404 <tr><th>Type</th><th>Description</th></tr>
1405 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1406 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1407 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1408 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1409 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1410 </tbody>
1411</table>
1412
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1413</div>
1414
1415<!-- _______________________________________________________________________ -->
1416<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1417
1418<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1419
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1420<h5>Overview:</h5>
1421<p>The void type does not represent any value and has no size.</p>
1422
1423<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1424<pre>
1425 void
1426</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1427
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1428</div>
1429
1430<!-- _______________________________________________________________________ -->
1431<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1432
1433<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1434
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1435<h5>Overview:</h5>
1436<p>The label type represents code labels.</p>
1437
1438<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1439<pre>
1440 label
1441</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1442
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1443</div>
1444
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
1446<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1447
1448<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1449
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1450<h5>Overview:</h5>
1451<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1452 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1453 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1454
1455<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1456<pre>
1457 metadata
1458</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1459
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1460</div>
1461
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1462
1463<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1464<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1465
1466<div class="doc_text">
1467
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1468<p>The real power in LLVM comes from the derived types in the system. This is
1469 what allows a programmer to represent arrays, functions, pointers, and other
1470 useful types. Note that these derived types may be recursive: For example,
1471 it is possible to have a two dimensional array.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1472
1473</div>
1474
1475<!-- _______________________________________________________________________ -->
1476<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1477
1478<div class="doc_text">
1479
1480<h5>Overview:</h5>
1481<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1482 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1483 2^23-1 (about 8 million) can be specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1484
1485<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1486<pre>
1487 iN
1488</pre>
1489
1490<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1491 value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1492
1493<h5>Examples:</h5>
1494<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1495 <tr class="layout">
1496 <td class="left"><tt>i1</tt></td>
1497 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1498 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1499 <tr class="layout">
1500 <td class="left"><tt>i32</tt></td>
1501 <td class="left">a 32-bit integer.</td>
1502 </tr>
1503 <tr class="layout">
1504 <td class="left"><tt>i1942652</tt></td>
1505 <td class="left">a really big integer of over 1 million bits.</td>
1506 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1507</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1508
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1509<p>Note that the code generator does not yet support large integer types to be
1510 used as function return types. The specific limit on how large a return type
1511 the code generator can currently handle is target-dependent; currently it's
1512 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1514</div>
1515
1516<!-- _______________________________________________________________________ -->
1517<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1518
1519<div class="doc_text">
1520
1521<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1522<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1523 sequentially in memory. The array type requires a size (number of elements)
1524 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1525
1526<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1527<pre>
1528 [&lt;# elements&gt; x &lt;elementtype&gt;]
1529</pre>
1530
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1531<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1532 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1533
1534<h5>Examples:</h5>
1535<table class="layout">
1536 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1537 <td class="left"><tt>[40 x i32]</tt></td>
1538 <td class="left">Array of 40 32-bit integer values.</td>
1539 </tr>
1540 <tr class="layout">
1541 <td class="left"><tt>[41 x i32]</tt></td>
1542 <td class="left">Array of 41 32-bit integer values.</td>
1543 </tr>
1544 <tr class="layout">
1545 <td class="left"><tt>[4 x i8]</tt></td>
1546 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547 </tr>
1548</table>
1549<p>Here are some examples of multidimensional arrays:</p>
1550<table class="layout">
1551 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1552 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1553 <td class="left">3x4 array of 32-bit integer values.</td>
1554 </tr>
1555 <tr class="layout">
1556 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1557 <td class="left">12x10 array of single precision floating point values.</td>
1558 </tr>
1559 <tr class="layout">
1560 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1561 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1562 </tr>
1563</table>
1564
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1565<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1566 length array. Normally, accesses past the end of an array are undefined in
1567 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1568 a special case, however, zero length arrays are recognized to be variable
1569 length. This allows implementation of 'pascal style arrays' with the LLVM
1570 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1571
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1572<p>Note that the code generator does not yet support large aggregate types to be
1573 used as function return types. The specific limit on how large an aggregate
1574 return type the code generator can currently handle is target-dependent, and
1575 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1577</div>
1578
1579<!-- _______________________________________________________________________ -->
1580<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1582<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1584<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1585<p>The function type can be thought of as a function signature. It consists of
1586 a return type and a list of formal parameter types. The return type of a
1587 function type is a scalar type, a void type, or a struct type. If the return
1588 type is a struct type then all struct elements must be of first class types,
1589 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1591<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1592<pre>
1593 &lt;returntype list&gt; (&lt;parameter list&gt;)
1594</pre>
1595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1596<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]1597 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1598 which indicates that the function takes a variable number of arguments.
1599 Variable argument functions can access their arguments with
1600 the <a href="#int_varargs">variable argument handling intrinsic</a>
1601 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1602 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1604<h5>Examples:</h5>
1605<table class="layout">
1606 <tr class="layout">
1607 <td class="left"><tt>i32 (i32)</tt></td>
1608 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1609 </td>
1610 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1611 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1612 </tt></td>
1613 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1614 an <tt>i16</tt> that should be sign extended and a
1615 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1616 <tt>float</tt>.
1617 </td>
1618 </tr><tr class="layout">
1619 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1620 <td class="left">A vararg function that takes at least one
1621 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1622 which returns an integer. This is the signature for <tt>printf</tt> in
1623 LLVM.
1624 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1625 </tr><tr class="layout">
1626 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1627 <td class="left">A function taking an <tt>i32</tt>, returning two
1628 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1629 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630 </tr>
1631</table>
1632
1633</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1635<!-- _______________________________________________________________________ -->
1636<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1638<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1640<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1641<p>The structure type is used to represent a collection of data members together
1642 in memory. The packing of the field types is defined to match the ABI of the
1643 underlying processor. The elements of a structure may be any type that has a
1644 size.</p>
1645
1646<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1647 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1648 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1650<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1651<pre>
1652 { &lt;type list&gt; }
1653</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1655<h5>Examples:</h5>
1656<table class="layout">
1657 <tr class="layout">
1658 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1659 <td class="left">A triple of three <tt>i32</tt> values</td>
1660 </tr><tr class="layout">
1661 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1662 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1663 second element is a <a href="#t_pointer">pointer</a> to a
1664 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1665 an <tt>i32</tt>.</td>
1666 </tr>
1667</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1668
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1669<p>Note that the code generator does not yet support large aggregate types to be
1670 used as function return types. The specific limit on how large an aggregate
1671 return type the code generator can currently handle is target-dependent, and
1672 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1674</div>
1675
1676<!-- _______________________________________________________________________ -->
1677<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1678</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1680<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1682<h5>Overview:</h5>
1683<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1684 together in memory. There is no padding between fields. Further, the
1685 alignment of a packed structure is 1 byte. The elements of a packed
1686 structure may be any type that has a size.</p>
1687
1688<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1689 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1690 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1692<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1693<pre>
1694 &lt; { &lt;type list&gt; } &gt;
1695</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1697<h5>Examples:</h5>
1698<table class="layout">
1699 <tr class="layout">
1700 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1701 <td class="left">A triple of three <tt>i32</tt> values</td>
1702 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1703 <td class="left">
1704<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1705 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1706 second element is a <a href="#t_pointer">pointer</a> to a
1707 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1708 an <tt>i32</tt>.</td>
1709 </tr>
1710</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1712</div>
1713
1714<!-- _______________________________________________________________________ -->
1715<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1717<div class="doc_text">
1718
1719<h5>Overview:</h5>
1720<p>As in many languages, the pointer type represents a pointer or reference to
1721 another object, which must live in memory. Pointer types may have an optional
1722 address space attribute defining the target-specific numbered address space
1723 where the pointed-to object resides. The default address space is zero.</p>
1724
1725<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1726 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1728<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1729<pre>
1730 &lt;type&gt; *
1731</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1733<h5>Examples:</h5>
1734<table class="layout">
1735 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1736 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1737 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1738 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1739 </tr>
1740 <tr class="layout">
1741 <td class="left"><tt>i32 (i32 *) *</tt></td>
1742 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1743 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1744 <tt>i32</tt>.</td>
1745 </tr>
1746 <tr class="layout">
1747 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1748 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1749 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1750 </tr>
1751</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1753</div>
1754
1755<!-- _______________________________________________________________________ -->
1756<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1758<div class="doc_text">
1759
1760<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1761<p>A vector type is a simple derived type that represents a vector of elements.
1762 Vector types are used when multiple primitive data are operated in parallel
1763 using a single instruction (SIMD). A vector type requires a size (number of
1764 elements) and an underlying primitive data type. Vectors must have a power
1765 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1766 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767
1768<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1769<pre>
1770 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1771</pre>
1772
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1773<p>The number of elements is a constant integer value; elementtype may be any
1774 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775
1776<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777<table class="layout">
1778 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1779 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1780 <td class="left">Vector of 4 32-bit integer values.</td>
1781 </tr>
1782 <tr class="layout">
1783 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1784 <td class="left">Vector of 8 32-bit floating-point values.</td>
1785 </tr>
1786 <tr class="layout">
1787 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1788 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1789 </tr>
1790</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1791
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1792<p>Note that the code generator does not yet support large vector types to be
1793 used as function return types. The specific limit on how large a vector
1794 return type codegen can currently handle is target-dependent; currently it's
1795 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1797</div>
1798
1799<!-- _______________________________________________________________________ -->
1800<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1801<div class="doc_text">
1802
1803<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1804<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1805 corresponds (for example) to the C notion of a forward declared structure
1806 type. In LLVM, opaque types can eventually be resolved to any type (not just
1807 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1808
1809<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1810<pre>
1811 opaque
1812</pre>
1813
1814<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1815<table class="layout">
1816 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1817 <td class="left"><tt>opaque</tt></td>
1818 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1819 </tr>
1820</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1821
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1822</div>
1823
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1824<!-- ======================================================================= -->
1825<div class="doc_subsection">
1826 <a name="t_uprefs">Type Up-references</a>
1827</div>
1828
1829<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1830
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1831<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1832<p>An "up reference" allows you to refer to a lexically enclosing type without
1833 requiring it to have a name. For instance, a structure declaration may
1834 contain a pointer to any of the types it is lexically a member of. Example
1835 of up references (with their equivalent as named type declarations)
1836 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1837
1838<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1839 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1840 { \2 }* %y = type { %y }*
1841 \1* %z = type %z*
1842</pre>
1843
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1844<p>An up reference is needed by the asmprinter for printing out cyclic types
1845 when there is no declared name for a type in the cycle. Because the
1846 asmprinter does not want to print out an infinite type string, it needs a
1847 syntax to handle recursive types that have no names (all names are optional
1848 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1849
1850<h5>Syntax:</h5>
1851<pre>
1852 \&lt;level&gt;
1853</pre>
1854
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1855<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]1856
1857<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1858<table class="layout">
1859 <tr class="layout">
1860 <td class="left"><tt>\1*</tt></td>
1861 <td class="left">Self-referential pointer.</td>
1862 </tr>
1863 <tr class="layout">
1864 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1865 <td class="left">Recursive structure where the upref refers to the out-most
1866 structure.</td>
1867 </tr>
1868</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1869
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1870</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1871
1872<!-- *********************************************************************** -->
1873<div class="doc_section"> <a name="constants">Constants</a> </div>
1874<!-- *********************************************************************** -->
1875
1876<div class="doc_text">
1877
1878<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1879 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1880
1881</div>
1882
1883<!-- ======================================================================= -->
1884<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1885
1886<div class="doc_text">
1887
1888<dl>
1889 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1890 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1891 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1892
1893 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1894 <dd>Standard integers (such as '4') are constants of
1895 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1896 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1897
1898 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1899 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1900 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1901 notation (see below). The assembler requires the exact decimal value of a
1902 floating-point constant. For example, the assembler accepts 1.25 but
1903 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1904 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1905
1906 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1908 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1909</dl>
1910
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1911<p>The one non-intuitive notation for constants is the hexadecimal form of
1912 floating point constants. For example, the form '<tt>double
1913 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1914 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1915 constants are required (and the only time that they are generated by the
1916 disassembler) is when a floating point constant must be emitted but it cannot
1917 be represented as a decimal floating point number in a reasonable number of
1918 digits. For example, NaN's, infinities, and other special values are
1919 represented in their IEEE hexadecimal format so that assembly and disassembly
1920 do not cause any bits to change in the constants.</p>
1921
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1922<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1923 represented using the 16-digit form shown above (which matches the IEEE754
1924 representation for double); float values must, however, be exactly
1925 representable as IEE754 single precision. Hexadecimal format is always used
1926 for long double, and there are three forms of long double. The 80-bit format
1927 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1928 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1929 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1930 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1931 currently supported target uses this format. Long doubles will only work if
1932 they match the long double format on your target. All hexadecimal formats
1933 are big-endian (sign bit at the left).</p>
1934
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1935</div>
1936
1937<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1938<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1939<a name="aggregateconstants"></a> <!-- old anchor -->
1940<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1941</div>
1942
1943<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1944
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1945<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1946 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1947
1948<dl>
1949 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1950 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1951 type definitions (a comma separated list of elements, surrounded by braces
1952 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1953 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1954 Structure constants must have <a href="#t_struct">structure type</a>, and
1955 the number and types of elements must match those specified by the
1956 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1957
1958 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1959 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1960 definitions (a comma separated list of elements, surrounded by square
1961 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1962 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1963 the number and types of elements must match those specified by the
1964 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1965
1966 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1968 definitions (a comma separated list of elements, surrounded by
1969 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1970 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1971 have <a href="#t_vector">vector type</a>, and the number and types of
1972 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1973
1974 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1975 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1976 value to zero of <em>any</em> type, including scalar and aggregate types.
1977 This is often used to avoid having to print large zero initializers
1978 (e.g. for large arrays) and is always exactly equivalent to using explicit
1979 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1980
1981 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1982 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1983 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1984 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1985 be interpreted as part of the instruction stream, metadata is a place to
1986 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1987</dl>
1988
1989</div>
1990
1991<!-- ======================================================================= -->
1992<div class="doc_subsection">
1993 <a name="globalconstants">Global Variable and Function Addresses</a>
1994</div>
1995
1996<div class="doc_text">
1997
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1998<p>The addresses of <a href="#globalvars">global variables</a>
1999 and <a href="#functionstructure">functions</a> are always implicitly valid
2000 (link-time) constants. These constants are explicitly referenced when
2001 the <a href="#identifiers">identifier for the global</a> is used and always
2002 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2003 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2004
2005<div class="doc_code">
2006<pre>
2007@X = global i32 17
2008@Y = global i32 42
2009@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2010</pre>
2011</div>
2012
2013</div>
2014
2015<!-- ======================================================================= -->
2016<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2017<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2018
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame^]2019<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
2020 indicates that the user of the value may recieve an unspecified bit-pattern.
2021 Undefined values may be of any type (other than label or void) and be used
2022 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2023
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame^]2024<p>Undefined values are useful, because it indicates to the compiler that the
2025 program is well defined no matter what value is used. This gives the
2026 compiler more freedom to optimize. Here are some examples of (potentially
2027 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2028
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame^]2029
2030<div class="doc_code">
2031<pre>
2032 %A = add %X, undef
2033 %B = sub %X, undef
2034 %C = xor %X, undef
2035Safe:
2036 %A = undef
2037 %B = undef
2038 %C = undef
2039</pre>
2040</div>
2041
2042<p>This is safe because all of the output bits are affected by the undef bits.
2043Any output bit can have a zero or one depending on the input bits.</p>
2044
2045<div class="doc_code">
2046<pre>
2047 %A = or %X, undef
2048 %B = and %X, undef
2049Safe:
2050 %A = -1
2051 %B = 0
2052Unsafe:
2053 %A = undef
2054 %B = undef
2055</pre>
2056</div>
2057
2058<p>These logical operations have bits that are not always affected by the input.
2059For example, if "%X" has a zero bit, then the output of the 'and' operation will
2060always be a zero, no matter what the corresponding bit from the undef is. As
2061such, it is unsafe to optimizer or assume that the result of the and is undef.
2062However, it is safe to assume that all bits of the undef are 0, and optimize the
2063and to 0. Likewise, it is safe to assume that all the bits of the undef operand
2064to the or could be set, allowing the or to be folded to -1.</p>
2065
2066<div class="doc_code">
2067<pre>
2068 %A = select undef, %X, %Y
2069 %B = select undef, 42, %Y
2070 %C = select %X, %Y, undef
2071Safe:
2072 %A = %X (or %Y)
2073 %B = 42 (or %Y)
2074 %C = %Y
2075Unsafe:
2076 %A = undef
2077 %B = undef
2078 %C = undef
2079</pre>
2080</div>
2081
2082<p>This set of examples show that undefined select (and conditional branch)
2083conditions can go "either way" but they have to come from one of the two
2084operands. In the %A example, if %X and %Y were both known to have a clear low
2085bit, then %A would have to have a cleared low bit. However, in the %C example,
2086the optimizer is allowed to assume that the undef operand could be the same as
2087%Y, allowing the whole select to be eliminated.</p>
2088
2089
2090<div class="doc_code">
2091<pre>
2092 %A = xor undef, undef
2093
2094 %B = undef
2095 %C = xor %B, %B
2096
2097 %D = undef
2098 %E = icmp lt %D, 4
2099 %F = icmp gte %D, 4
2100
2101Safe:
2102 %A = undef
2103 %B = undef
2104 %C = undef
2105 %D = undef
2106 %E = undef
2107 %F = undef
2108</pre>
2109</div>
2110
2111<p>This example points out that two undef operands are not necessarily the same.
2112This can be surprising to people (and also matches C semantics) where they
2113assume that "X^X" is always zero, even if X is undef. This isn't true for a
2114number of reasons, but the short answer is that an undef "variable" can
2115arbitrarily change its value over its "live range". This is true because the
2116"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2117logically read from arbitrary registers that happen to be around when needed,
2118so the value is not neccesarily consistent over time. In fact, %A and %C need
2119to have the same semantics of the core LLVM "replace all uses with" concept
2120would not hold.</p>
2121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2122</div>
2123
2124<!-- ======================================================================= -->
2125<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2126</div>
2127
2128<div class="doc_text">
2129
2130<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2131 to be used as constants. Constant expressions may be of
2132 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2133 operation that does not have side effects (e.g. load and call are not
2134 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2135
2136<dl>
2137 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2138 <dd>Truncate a constant to another type. The bit size of CST must be larger
2139 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2140
2141 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2142 <dd>Zero extend a constant to another type. The bit size of CST must be
2143 smaller or equal to the bit size of TYPE. Both types must be
2144 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2145
2146 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2147 <dd>Sign extend a constant to another type. The bit size of CST must be
2148 smaller or equal to the bit size of TYPE. Both types must be
2149 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2150
2151 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2152 <dd>Truncate a floating point constant to another floating point type. The
2153 size of CST must be larger than the size of TYPE. Both types must be
2154 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2155
2156 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2157 <dd>Floating point extend a constant to another type. The size of CST must be
2158 smaller or equal to the size of TYPE. Both types must be floating
2159 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2160
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2161 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2163 constant. TYPE must be a scalar or vector integer type. CST must be of
2164 scalar or vector floating point type. Both CST and TYPE must be scalars,
2165 or vectors of the same number of elements. If the value won't fit in the
2166 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2167
2168 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2169 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2170 constant. TYPE must be a scalar or vector integer type. CST must be of
2171 scalar or vector floating point type. Both CST and TYPE must be scalars,
2172 or vectors of the same number of elements. If the value won't fit in the
2173 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2174
2175 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2176 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2177 constant. TYPE must be a scalar or vector floating point type. CST must be
2178 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2179 vectors of the same number of elements. If the value won't fit in the
2180 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2181
2182 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2183 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2184 constant. TYPE must be a scalar or vector floating point type. CST must be
2185 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2186 vectors of the same number of elements. If the value won't fit in the
2187 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2188
2189 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2190 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2191 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2192 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2193 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2194
2195 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2196 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2197 type. CST must be of integer type. The CST value is zero extended,
2198 truncated, or unchanged to make it fit in a pointer size. This one is
2199 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2200
2201 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2202 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2203 are the same as those for the <a href="#i_bitcast">bitcast
2204 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2205
2206 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2207 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2209 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2210 instruction, the index list may have zero or more indexes, which are
2211 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2212
2213 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2214 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2215
2216 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2217 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2218
2219 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2220 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2221
2222 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2223 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2224 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2225
2226 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2227 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2228 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2229
2230 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2231 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2232 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2233
2234 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2235 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2236 be any of the <a href="#binaryops">binary</a>
2237 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2238 on operands are the same as those for the corresponding instruction
2239 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2240</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242</div>
2243
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2244<!-- ======================================================================= -->
2245<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2246</div>
2247
2248<div class="doc_text">
2249
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2250<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2251 stream without affecting the behaviour of the program. There are two
2252 metadata primitives, strings and nodes. All metadata has the
2253 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2254 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2255
2256<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2257 any character by escaping non-printable characters with "\xx" where "xx" is
2258 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2259
2260<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2261 (a comma separated list of elements, surrounded by braces and preceeded by an
2262 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2263 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2264
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2265<p>A metadata node will attempt to track changes to the values it holds. In the
2266 event that a value is deleted, it will be replaced with a typeless
2267 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2268
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2269<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2270 the program that isn't available in the instructions, or that isn't easily
2271 computable. Similarly, the code generator may expect a certain metadata
2272 format to be used to express debugging information.</p>
2273
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2274</div>
2275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2276<!-- *********************************************************************** -->
2277<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2278<!-- *********************************************************************** -->
2279
2280<!-- ======================================================================= -->
2281<div class="doc_subsection">
2282<a name="inlineasm">Inline Assembler Expressions</a>
2283</div>
2284
2285<div class="doc_text">
2286
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2287<p>LLVM supports inline assembler expressions (as opposed
2288 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2289 a special value. This value represents the inline assembler as a string
2290 (containing the instructions to emit), a list of operand constraints (stored
2291 as a string), and a flag that indicates whether or not the inline asm
2292 expression has side effects. An example inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2293
2294<div class="doc_code">
2295<pre>
2296i32 (i32) asm "bswap $0", "=r,r"
2297</pre>
2298</div>
2299
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2300<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2301 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2302 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2303
2304<div class="doc_code">
2305<pre>
2306%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2307</pre>
2308</div>
2309
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2310<p>Inline asms with side effects not visible in the constraint list must be
2311 marked as having side effects. This is done through the use of the
2312 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2313
2314<div class="doc_code">
2315<pre>
2316call void asm sideeffect "eieio", ""()
2317</pre>
2318</div>
2319
2320<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2321 documented here. Constraints on what can be done (e.g. duplication, moving,
2322 etc need to be documented). This is probably best done by reference to
2323 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2324
2325</div>
2326
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2327
2328<!-- *********************************************************************** -->
2329<div class="doc_section">
2330 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2331</div>
2332<!-- *********************************************************************** -->
2333
2334<p>LLVM has a number of "magic" global variables that contain data that affect
2335code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2336of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2337section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2338by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2339
2340<!-- ======================================================================= -->
2341<div class="doc_subsection">
2342<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2343</div>
2344
2345<div class="doc_text">
2346
2347<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2348href="#linkage_appending">appending linkage</a>. This array contains a list of
2349pointers to global variables and functions which may optionally have a pointer
2350cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2351
2352<pre>
2353 @X = global i8 4
2354 @Y = global i32 123
2355
2356 @llvm.used = appending global [2 x i8*] [
2357 i8* @X,
2358 i8* bitcast (i32* @Y to i8*)
2359 ], section "llvm.metadata"
2360</pre>
2361
2362<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2363compiler, assembler, and linker are required to treat the symbol as if there is
2364a reference to the global that it cannot see. For example, if a variable has
2365internal linkage and no references other than that from the <tt>@llvm.used</tt>
2366list, it cannot be deleted. This is commonly used to represent references from
2367inline asms and other things the compiler cannot "see", and corresponds to
2368"attribute((used))" in GNU C.</p>
2369
2370<p>On some targets, the code generator must emit a directive to the assembler or
2371object file to prevent the assembler and linker from molesting the symbol.</p>
2372
2373</div>
2374
2375<!-- ======================================================================= -->
2376<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2377<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2378</div>
2379
2380<div class="doc_text">
2381
2382<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2383<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2384touching the symbol. On targets that support it, this allows an intelligent
2385linker to optimize references to the symbol without being impeded as it would be
2386by <tt>@llvm.used</tt>.</p>
2387
2388<p>This is a rare construct that should only be used in rare circumstances, and
2389should not be exposed to source languages.</p>
2390
2391</div>
2392
2393<!-- ======================================================================= -->
2394<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2395<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2396</div>
2397
2398<div class="doc_text">
2399
2400<p>TODO: Describe this.</p>
2401
2402</div>
2403
2404<!-- ======================================================================= -->
2405<div class="doc_subsection">
2406<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2407</div>
2408
2409<div class="doc_text">
2410
2411<p>TODO: Describe this.</p>
2412
2413</div>
2414
2415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2416<!-- *********************************************************************** -->
2417<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2418<!-- *********************************************************************** -->
2419
2420<div class="doc_text">
2421
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2422<p>The LLVM instruction set consists of several different classifications of
2423 instructions: <a href="#terminators">terminator
2424 instructions</a>, <a href="#binaryops">binary instructions</a>,
2425 <a href="#bitwiseops">bitwise binary instructions</a>,
2426 <a href="#memoryops">memory instructions</a>, and
2427 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2428
2429</div>
2430
2431<!-- ======================================================================= -->
2432<div class="doc_subsection"> <a name="terminators">Terminator
2433Instructions</a> </div>
2434
2435<div class="doc_text">
2436
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2437<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2438 in a program ends with a "Terminator" instruction, which indicates which
2439 block should be executed after the current block is finished. These
2440 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2441 control flow, not values (the one exception being the
2442 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2443
2444<p>There are six different terminator instructions: the
2445 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2446 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2447 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2448 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2449 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2450 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2451
2452</div>
2453
2454<!-- _______________________________________________________________________ -->
2455<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2456Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2457
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2458<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2459
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2461<pre>
2462 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]2463 ret void <i>; Return from void function</i>
2464</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2466<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2467<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2468 a value) from a function back to the caller.</p>
2469
2470<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2471 value and then causes control flow, and one that just causes control flow to
2472 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2474<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2475<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2476 return value. The type of the return value must be a
2477 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2478
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2479<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2480 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2481 value or a return value with a type that does not match its type, or if it
2482 has a void return type and contains a '<tt>ret</tt>' instruction with a
2483 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2485<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2486<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2487 the calling function's context. If the caller is a
2488 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2489 instruction after the call. If the caller was an
2490 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2491 the beginning of the "normal" destination block. If the instruction returns
2492 a value, that value shall set the call or invoke instruction's return
2493 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2495<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2496<pre>
2497 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2498 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2499 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]2500</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2501
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2502<p>Note that the code generator does not yet fully support large
2503 return values. The specific sizes that are currently supported are
2504 dependent on the target. For integers, on 32-bit targets the limit
2505 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2506 For aggregate types, the current limits are dependent on the element
2507 types; for example targets are often limited to 2 total integer
2508 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2510</div>
2511<!-- _______________________________________________________________________ -->
2512<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2514<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2516<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2517<pre>
2518 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]2519</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2521<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2522<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2523 different basic block in the current function. There are two forms of this
2524 instruction, corresponding to a conditional branch and an unconditional
2525 branch.</p>
2526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2527<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2528<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2529 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2530 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2531 target.</p>
2532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2533<h5>Semantics:</h5>
2534<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2535 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2536 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2537 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2539<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2540<pre>
2541Test:
2542 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2543 br i1 %cond, label %IfEqual, label %IfUnequal
2544IfEqual:
2545 <a href="#i_ret">ret</a> i32 1
2546IfUnequal:
2547 <a href="#i_ret">ret</a> i32 0
2548</pre>
2549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552<!-- _______________________________________________________________________ -->
2553<div class="doc_subsubsection">
2554 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2555</div>
2556
2557<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2558
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2559<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2560<pre>
2561 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2562</pre>
2563
2564<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2565<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]2566 several different places. It is a generalization of the '<tt>br</tt>'
2567 instruction, allowing a branch to occur to one of many possible
2568 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2569
2570<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2571<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2572 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2573 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2574 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575
2576<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2578 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2579 is searched for the given value. If the value is found, control flow is
2580 transfered to the corresponding destination; otherwise, control flow is
2581 transfered to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582
2583<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2584<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2585 <tt>switch</tt> instruction, this instruction may be code generated in
2586 different ways. For example, it could be generated as a series of chained
2587 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2588
2589<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590<pre>
2591 <i>; Emulate a conditional br instruction</i>
2592 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2593 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594
2595 <i>; Emulate an unconditional br instruction</i>
2596 switch i32 0, label %dest [ ]
2597
2598 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2599 switch i32 %val, label %otherwise [ i32 0, label %onzero
2600 i32 1, label %onone
2601 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604</div>
2605
2606<!-- _______________________________________________________________________ -->
2607<div class="doc_subsubsection">
2608 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2609</div>
2610
2611<div class="doc_text">
2612
2613<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2615 &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]2616 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2617</pre>
2618
2619<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2620<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2621 function, with the possibility of control flow transfer to either the
2622 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2623 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2624 control flow will return to the "normal" label. If the callee (or any
2625 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2626 instruction, control is interrupted and continued at the dynamically nearest
2627 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628
2629<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2630<p>This instruction requires several arguments:</p>
2631
2632<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2633 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2634 convention</a> the call should use. If none is specified, the call
2635 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2636
2637 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2638 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2639 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2641 <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]2642 function value being invoked. In most cases, this is a direct function
2643 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2644 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645
2646 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2647 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2648
2649 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2650 signature argument types. If the function signature indicates the
2651 function accepts a variable number of arguments, the extra arguments can
2652 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653
2654 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2655 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656
2657 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2658 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2660 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2661 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2662 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663</ol>
2664
2665<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2666<p>This instruction is designed to operate as a standard
2667 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2668 primary difference is that it establishes an association with a label, which
2669 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670
2671<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2672 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2673 exception. Additionally, this is important for implementation of
2674 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2675
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2676<p>For the purposes of the SSA form, the definition of the value returned by the
2677 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2678 block to the "normal" label. If the callee unwinds then no return value is
2679 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2680
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2681<h5>Example:</h5>
2682<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2683 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2684 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2685 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2686 unwind label %TestCleanup <i>; {i32}:retval set</i>
2687</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2688
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2689</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2690
2691<!-- _______________________________________________________________________ -->
2692
2693<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2694Instruction</a> </div>
2695
2696<div class="doc_text">
2697
2698<h5>Syntax:</h5>
2699<pre>
2700 unwind
2701</pre>
2702
2703<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2704<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2705 at the first callee in the dynamic call stack which used
2706 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2707 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2708
2709<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2710<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2711 immediately halt. The dynamic call stack is then searched for the
2712 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2713 Once found, execution continues at the "exceptional" destination block
2714 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2715 instruction in the dynamic call chain, undefined behavior results.</p>
2716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2717</div>
2718
2719<!-- _______________________________________________________________________ -->
2720
2721<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2722Instruction</a> </div>
2723
2724<div class="doc_text">
2725
2726<h5>Syntax:</h5>
2727<pre>
2728 unreachable
2729</pre>
2730
2731<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2733 instruction is used to inform the optimizer that a particular portion of the
2734 code is not reachable. This can be used to indicate that the code after a
2735 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736
2737<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2740</div>
2741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2742<!-- ======================================================================= -->
2743<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2744
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2745<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2746
2747<p>Binary operators are used to do most of the computation in a program. They
2748 require two operands of the same type, execute an operation on them, and
2749 produce a single value. The operands might represent multiple data, as is
2750 the case with the <a href="#t_vector">vector</a> data type. The result value
2751 has the same type as its operands.</p>
2752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2753<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2755</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2758<div class="doc_subsubsection">
2759 <a name="i_add">'<tt>add</tt>' Instruction</a>
2760</div>
2761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2762<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2764<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2765<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2766 &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]2767 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2768 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2769 &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]2770</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2772<h5>Overview:</h5>
2773<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2775<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2776<p>The two arguments to the '<tt>add</tt>' instruction must
2777 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2778 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2780<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2781<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2782
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2783<p>If the sum has unsigned overflow, the result returned is the mathematical
2784 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]2785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2786<p>Because LLVM integers use a two's complement representation, this instruction
2787 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2788
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2789<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2790 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2791 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2792 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2795<pre>
2796 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2797</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2799</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2801<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2802<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2803 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2804</div>
2805
2806<div class="doc_text">
2807
2808<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2809<pre>
2810 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2811</pre>
2812
2813<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2814<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2815
2816<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2817<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2818 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2819 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2820
2821<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2822<p>The value produced is the floating point sum of the two operands.</p>
2823
2824<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2825<pre>
2826 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2827</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2828
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2829</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2830
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2831<!-- _______________________________________________________________________ -->
2832<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2833 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2834</div>
2835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2836<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2839<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2840 &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]2841 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2842 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2843 &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]2844</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846<h5>Overview:</h5>
2847<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2848 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2849
2850<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2851 '<tt>neg</tt>' instruction present in most other intermediate
2852 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2855<p>The two arguments to the '<tt>sub</tt>' instruction must
2856 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2857 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2858
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2859<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2860<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2861
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2862<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2863 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2864 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2865
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2866<p>Because LLVM integers use a two's complement representation, this instruction
2867 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2868
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2869<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2870 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2871 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2872 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2874<h5>Example:</h5>
2875<pre>
2876 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2877 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2878</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2880</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2882<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2883<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2884 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2885</div>
2886
2887<div class="doc_text">
2888
2889<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2890<pre>
2891 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2892</pre>
2893
2894<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2895<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2896 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2897
2898<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2899 '<tt>fneg</tt>' instruction present in most other intermediate
2900 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2901
2902<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2903<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2904 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2905 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2906
2907<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2908<p>The value produced is the floating point difference of the two operands.</p>
2909
2910<h5>Example:</h5>
2911<pre>
2912 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2913 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2914</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2915
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2916</div>
2917
2918<!-- _______________________________________________________________________ -->
2919<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2920 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2921</div>
2922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2923<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2926<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2927 &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]2928 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2929 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2930 &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]2931</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2932
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2933<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2934<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2936<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2937<p>The two arguments to the '<tt>mul</tt>' instruction must
2938 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2939 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2941<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2942<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2943
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2944<p>If the result of the multiplication has unsigned overflow, the result
2945 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2946 width of the result.</p>
2947
2948<p>Because LLVM integers use a two's complement representation, and the result
2949 is the same width as the operands, this instruction returns the correct
2950 result for both signed and unsigned integers. If a full product
2951 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2952 be sign-extended or zero-extended as appropriate to the width of the full
2953 product.</p>
2954
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2955<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2956 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2957 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
2958 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2960<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2961<pre>
2962 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2963</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2967<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2968<div class="doc_subsubsection">
2969 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2970</div>
2971
2972<div class="doc_text">
2973
2974<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2975<pre>
2976 &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]2977</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2978
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2979<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2980<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2981
2982<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2983<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2984 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2985 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2986
2987<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2988<p>The value produced is the floating point product of the two operands.</p>
2989
2990<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2991<pre>
2992 &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]2993</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2994
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2995</div>
2996
2997<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2998<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2999</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3001<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3002
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3003<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3004<pre>
3005 &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]3006</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3007
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3008<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3009<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3010
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3011<h5>Arguments:</h5>
3012<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3013 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3014 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3016<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3017<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3018
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3019<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3020 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3021
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3022<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3024<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3025<pre>
3026 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3027</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3028
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3029</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3031<!-- _______________________________________________________________________ -->
3032<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3033</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3035<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3037<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3038<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3039 &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]3040 &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]3041</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3044<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3046<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3047<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3048 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3049 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3051<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052<p>The value produced is the signed integer quotient of the two operands rounded
3053 towards zero.</p>
3054
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3055<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3056 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3057
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3058<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3059 undefined behavior; this is a rare case, but can occur, for example, by doing
3060 a 32-bit division of -2147483648 by -1.</p>
3061
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3062<p>If the <tt>exact</tt> keyword is present, the result value of the
3063 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3064 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3066<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3067<pre>
3068 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3069</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3071</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3072
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3073<!-- _______________________________________________________________________ -->
3074<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3075Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3077<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3079<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3080<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3081 &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]3082</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3083
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084<h5>Overview:</h5>
3085<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3087<h5>Arguments:</h5>
3088<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3089 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3090 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3092<h5>Semantics:</h5>
3093<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3094
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3095<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3096<pre>
3097 &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]3098</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3100</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3102<!-- _______________________________________________________________________ -->
3103<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3104</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3105
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3106<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3107
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3109<pre>
3110 &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]3111</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3113<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3114<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3115 division of its two arguments.</p>
3116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3118<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3119 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3120 values. Both arguments must have identical types.</p>
3121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3122<h5>Semantics:</h5>
3123<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3124 This instruction always performs an unsigned division to get the
3125 remainder.</p>
3126
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3127<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3128 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3129
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3130<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3132<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3133<pre>
3134 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3135</pre>
3136
3137</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3140<div class="doc_subsubsection">
3141 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3142</div>
3143
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3144<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3146<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3147<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3148 &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]3149</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3150
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3151<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3152<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3153 division of its two operands. This instruction can also take
3154 <a href="#t_vector">vector</a> versions of the values in which case the
3155 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157<h5>Arguments:</h5>
3158<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3159 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3160 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162<h5>Semantics:</h5>
3163<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3165 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3166 a value. For more information about the difference,
3167 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3168 Math Forum</a>. For a table of how this is implemented in various languages,
3169 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3170 Wikipedia: modulo operation</a>.</p>
3171
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3172<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3173 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3174
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3175<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3176 Overflow also leads to undefined behavior; this is a rare case, but can
3177 occur, for example, by taking the remainder of a 32-bit division of
3178 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3179 lets srem be implemented using instructions that return both the result of
3180 the division and the remainder.)</p>
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; = srem 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_frem">'<tt>frem</tt>' Instruction</a> </div>
3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3194
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3195<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3196<pre>
3197 &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]3198</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3200<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3201<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3202 its two operands.</p>
3203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3204<h5>Arguments:</h5>
3205<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3206 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3207 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3209<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3210<p>This instruction returns the <i>remainder</i> of a division. The remainder
3211 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3213<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3214<pre>
3215 &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]3216</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3218</div>
3219
3220<!-- ======================================================================= -->
3221<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3222Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3224<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3225
3226<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3227 program. They are generally very efficient instructions and can commonly be
3228 strength reduced from other instructions. They require two operands of the
3229 same type, execute an operation on them, and produce a single value. The
3230 resulting value is the same type as its operands.</p>
3231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3232</div>
3233
3234<!-- _______________________________________________________________________ -->
3235<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3236Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3238<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3241<pre>
3242 &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]3243</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3245<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3246<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3247 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3249<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3250<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3251 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3252 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3254<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3255<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3256 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3257 is (statically or dynamically) negative or equal to or larger than the number
3258 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3259 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3260 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3261
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3262<h5>Example:</h5>
3263<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3264 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3265 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3266 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3267 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3268 &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]3269</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3270
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3271</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273<!-- _______________________________________________________________________ -->
3274<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3275Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3277<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3279<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3280<pre>
3281 &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]3282</pre>
3283
3284<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3285<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3286 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3287
3288<h5>Arguments:</h5>
3289<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3291 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3292
3293<h5>Semantics:</h5>
3294<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3295 significant bits of the result will be filled with zero bits after the shift.
3296 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3297 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3298 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3299 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3300
3301<h5>Example:</h5>
3302<pre>
3303 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3304 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3305 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3306 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3307 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3308 &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]3309</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3311</div>
3312
3313<!-- _______________________________________________________________________ -->
3314<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3315Instruction</a> </div>
3316<div class="doc_text">
3317
3318<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3319<pre>
3320 &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]3321</pre>
3322
3323<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3324<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3325 operand shifted to the right a specified number of bits with sign
3326 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327
3328<h5>Arguments:</h5>
3329<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3330 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3331 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3332
3333<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3334<p>This instruction always performs an arithmetic shift right operation, The
3335 most significant bits of the result will be filled with the sign bit
3336 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3337 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3338 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3339 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3340
3341<h5>Example:</h5>
3342<pre>
3343 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3344 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3345 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3346 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3347 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3348 &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]3349</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3351</div>
3352
3353<!-- _______________________________________________________________________ -->
3354<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3355Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3356
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3357<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3360<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3361 &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]3362</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3364<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3365<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3366 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3368<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3369<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3370 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3371 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3372
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3373<h5>Semantics:</h5>
3374<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376<table border="1" cellspacing="0" cellpadding="4">
3377 <tbody>
3378 <tr>
3379 <td>In0</td>
3380 <td>In1</td>
3381 <td>Out</td>
3382 </tr>
3383 <tr>
3384 <td>0</td>
3385 <td>0</td>
3386 <td>0</td>
3387 </tr>
3388 <tr>
3389 <td>0</td>
3390 <td>1</td>
3391 <td>0</td>
3392 </tr>
3393 <tr>
3394 <td>1</td>
3395 <td>0</td>
3396 <td>0</td>
3397 </tr>
3398 <tr>
3399 <td>1</td>
3400 <td>1</td>
3401 <td>1</td>
3402 </tr>
3403 </tbody>
3404</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3407<pre>
3408 &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]3409 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3410 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3411</pre>
3412</div>
3413<!-- _______________________________________________________________________ -->
3414<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3415
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3416<div class="doc_text">
3417
3418<h5>Syntax:</h5>
3419<pre>
3420 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3421</pre>
3422
3423<h5>Overview:</h5>
3424<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3425 two operands.</p>
3426
3427<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3428<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3429 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3430 values. Both arguments must have identical types.</p>
3431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3432<h5>Semantics:</h5>
3433<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3435<table border="1" cellspacing="0" cellpadding="4">
3436 <tbody>
3437 <tr>
3438 <td>In0</td>
3439 <td>In1</td>
3440 <td>Out</td>
3441 </tr>
3442 <tr>
3443 <td>0</td>
3444 <td>0</td>
3445 <td>0</td>
3446 </tr>
3447 <tr>
3448 <td>0</td>
3449 <td>1</td>
3450 <td>1</td>
3451 </tr>
3452 <tr>
3453 <td>1</td>
3454 <td>0</td>
3455 <td>1</td>
3456 </tr>
3457 <tr>
3458 <td>1</td>
3459 <td>1</td>
3460 <td>1</td>
3461 </tr>
3462 </tbody>
3463</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3464
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3465<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3466<pre>
3467 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3468 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3469 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3470</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3472</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3474<!-- _______________________________________________________________________ -->
3475<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3476Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3478<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3480<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481<pre>
3482 &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]3483</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3486<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3487 its two operands. The <tt>xor</tt> is used to implement the "one's
3488 complement" operation, which is the "~" operator in C.</p>
3489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3491<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3492 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3493 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3495<h5>Semantics:</h5>
3496<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3498<table border="1" cellspacing="0" cellpadding="4">
3499 <tbody>
3500 <tr>
3501 <td>In0</td>
3502 <td>In1</td>
3503 <td>Out</td>
3504 </tr>
3505 <tr>
3506 <td>0</td>
3507 <td>0</td>
3508 <td>0</td>
3509 </tr>
3510 <tr>
3511 <td>0</td>
3512 <td>1</td>
3513 <td>1</td>
3514 </tr>
3515 <tr>
3516 <td>1</td>
3517 <td>0</td>
3518 <td>1</td>
3519 </tr>
3520 <tr>
3521 <td>1</td>
3522 <td>1</td>
3523 <td>0</td>
3524 </tr>
3525 </tbody>
3526</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3528<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3529<pre>
3530 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3531 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3532 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3533 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3534</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3536</div>
3537
3538<!-- ======================================================================= -->
3539<div class="doc_subsection">
3540 <a name="vectorops">Vector Operations</a>
3541</div>
3542
3543<div class="doc_text">
3544
3545<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3546 target-independent manner. These instructions cover the element-access and
3547 vector-specific operations needed to process vectors effectively. While LLVM
3548 does directly support these vector operations, many sophisticated algorithms
3549 will want to use target-specific intrinsics to take full advantage of a
3550 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3551
3552</div>
3553
3554<!-- _______________________________________________________________________ -->
3555<div class="doc_subsubsection">
3556 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3557</div>
3558
3559<div class="doc_text">
3560
3561<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3562<pre>
3563 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3564</pre>
3565
3566<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3568 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3569
3570
3571<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3572<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3573 of <a href="#t_vector">vector</a> type. The second operand is an index
3574 indicating the position from which to extract the element. The index may be
3575 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3576
3577<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3578<p>The result is a scalar of the same type as the element type of
3579 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3580 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3581 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3582
3583<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3584<pre>
3585 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3586</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3587
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3588</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3589
3590<!-- _______________________________________________________________________ -->
3591<div class="doc_subsubsection">
3592 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3593</div>
3594
3595<div class="doc_text">
3596
3597<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3598<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3599 &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]3600</pre>
3601
3602<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3603<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3604 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3605
3606<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3607<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3608 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3609 whose type must equal the element type of the first operand. The third
3610 operand is an index indicating the position at which to insert the value.
3611 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3612
3613<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3615 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3616 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3617 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618
3619<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3620<pre>
3621 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3622</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624</div>
3625
3626<!-- _______________________________________________________________________ -->
3627<div class="doc_subsubsection">
3628 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3629</div>
3630
3631<div class="doc_text">
3632
3633<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3635 &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]3636</pre>
3637
3638<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3639<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3640 from two input vectors, returning a vector with the same element type as the
3641 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3642
3643<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3644<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3645 with types that match each other. The third argument is a shuffle mask whose
3646 element type is always 'i32'. The result of the instruction is a vector
3647 whose length is the same as the shuffle mask and whose element type is the
3648 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3649
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3650<p>The shuffle mask operand is required to be a constant vector with either
3651 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652
3653<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3654<p>The elements of the two input vectors are numbered from left to right across
3655 both of the vectors. The shuffle mask operand specifies, for each element of
3656 the result vector, which element of the two input vectors the result element
3657 gets. The element selector may be undef (meaning "don't care") and the
3658 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3659
3660<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3661<pre>
3662 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3663 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3664 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3665 &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]3666 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3667 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3668 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3669 &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]3670</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3672</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3673
3674<!-- ======================================================================= -->
3675<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3676 <a name="aggregateops">Aggregate Operations</a>
3677</div>
3678
3679<div class="doc_text">
3680
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3681<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3682
3683</div>
3684
3685<!-- _______________________________________________________________________ -->
3686<div class="doc_subsubsection">
3687 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3688</div>
3689
3690<div class="doc_text">
3691
3692<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3693<pre>
3694 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3695</pre>
3696
3697<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3698<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3699 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3700
3701<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3702<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3703 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3704 operands are constant indices to specify which value to extract in a similar
3705 manner as indices in a
3706 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3707
3708<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3709<p>The result is the value at the position in the aggregate specified by the
3710 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3711
3712<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3713<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3714 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3715</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3718
3719<!-- _______________________________________________________________________ -->
3720<div class="doc_subsubsection">
3721 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3722</div>
3723
3724<div class="doc_text">
3725
3726<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3727<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3728 &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]3729</pre>
3730
3731<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3732<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3733 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3734
3735
3736<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3737<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3738 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3739 second operand is a first-class value to insert. The following operands are
3740 constant indices indicating the position at which to insert the value in a
3741 similar manner as indices in a
3742 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3743 value to insert must have the same type as the value identified by the
3744 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3745
3746<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3747<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3748 that of <tt>val</tt> except that the value at the position specified by the
3749 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3750
3751<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3752<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3753 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3754</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3755
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3756</div>
3757
3758
3759<!-- ======================================================================= -->
3760<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3761 <a name="memoryops">Memory Access and Addressing Operations</a>
3762</div>
3763
3764<div class="doc_text">
3765
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3766<p>A key design point of an SSA-based representation is how it represents
3767 memory. In LLVM, no memory locations are in SSA form, which makes things
3768 very simple. This section describes how to read, write, allocate, and free
3769 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3770
3771</div>
3772
3773<!-- _______________________________________________________________________ -->
3774<div class="doc_subsubsection">
3775 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3776</div>
3777
3778<div class="doc_text">
3779
3780<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3781<pre>
3782 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3783</pre>
3784
3785<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3786<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3787 returns a pointer to it. The object is always allocated in the generic
3788 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3789
3790<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3791<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3792 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3793 system and returns a pointer of the appropriate type to the program. If
3794 "NumElements" is specified, it is the number of elements allocated, otherwise
3795 "NumElements" is defaulted to be one. If a constant alignment is specified,
3796 the value result of the allocation is guaranteed to be aligned to at least
3797 that boundary. If not specified, or if zero, the target can choose to align
3798 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3799
3800<p>'<tt>type</tt>' must be a sized type.</p>
3801
3802<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3803<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3804 pointer is returned. The result of a zero byte allocation is undefined. The
3805 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3806
3807<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3808<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3809 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3810
3811 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3812 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3813 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3814 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3815 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3816</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3817
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3818<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3820</div>
3821
3822<!-- _______________________________________________________________________ -->
3823<div class="doc_subsubsection">
3824 <a name="i_free">'<tt>free</tt>' Instruction</a>
3825</div>
3826
3827<div class="doc_text">
3828
3829<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3830<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3831 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3832</pre>
3833
3834<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3835<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3836 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3837
3838<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3839<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3840 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3841
3842<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3843<p>Access to the memory pointed to by the pointer is no longer defined after
3844 this instruction executes. If the pointer is null, the operation is a
3845 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3846
3847<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3848<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3849 %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]3850 free [4 x i8]* %array
3851</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3853</div>
3854
3855<!-- _______________________________________________________________________ -->
3856<div class="doc_subsubsection">
3857 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3858</div>
3859
3860<div class="doc_text">
3861
3862<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3863<pre>
3864 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3865</pre>
3866
3867<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3868<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3869 currently executing function, to be automatically released when this function
3870 returns to its caller. The object is always allocated in the generic address
3871 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3872
3873<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3874<p>The '<tt>alloca</tt>' instruction
3875 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3876 runtime stack, returning a pointer of the appropriate type to the program.
3877 If "NumElements" is specified, it is the number of elements allocated,
3878 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3879 specified, the value result of the allocation is guaranteed to be aligned to
3880 at least that boundary. If not specified, or if zero, the target can choose
3881 to align the allocation on any convenient boundary compatible with the
3882 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3883
3884<p>'<tt>type</tt>' may be any sized type.</p>
3885
3886<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3887<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3888 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3889 memory is automatically released when the function returns. The
3890 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3891 variables that must have an address available. When the function returns
3892 (either with the <tt><a href="#i_ret">ret</a></tt>
3893 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3894 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3895
3896<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3897<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3898 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3899 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3900 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3901 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3904</div>
3905
3906<!-- _______________________________________________________________________ -->
3907<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3908Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3910<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3913<pre>
3914 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3915 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3916</pre>
3917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3918<h5>Overview:</h5>
3919<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3921<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3922<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3923 from which to load. The pointer must point to
3924 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3925 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3926 number or order of execution of this <tt>load</tt> with other
3927 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3928 instructions. </p>
3929
3930<p>The optional constant "align" argument specifies the alignment of the
3931 operation (that is, the alignment of the memory address). A value of 0 or an
3932 omitted "align" argument means that the operation has the preferential
3933 alignment for the target. It is the responsibility of the code emitter to
3934 ensure that the alignment information is correct. Overestimating the
3935 alignment results in an undefined behavior. Underestimating the alignment may
3936 produce less efficient code. An alignment of 1 is always safe.</p>
3937
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3939<p>The location of memory pointed to is loaded. If the value being loaded is of
3940 scalar type then the number of bytes read does not exceed the minimum number
3941 of bytes needed to hold all bits of the type. For example, loading an
3942 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3943 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3944 is undefined if the value was not originally written using a store of the
3945 same type.</p>
3946
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3947<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3948<pre>
3949 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3950 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
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>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3956<!-- _______________________________________________________________________ -->
3957<div class="doc_subsubsection"> <a name="i_store">'<tt>store</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 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]3965 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3966</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3968<h5>Overview:</h5>
3969<p>The '<tt>store</tt>' instruction is used to write to 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>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3973 and an address at which to store it. The type of the
3974 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3975 the <a href="#t_firstclass">first class</a> type of the
3976 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3977 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3978 or order of execution of this <tt>store</tt> with other
3979 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3980 instructions.</p>
3981
3982<p>The optional constant "align" argument specifies the alignment of the
3983 operation (that is, the alignment of the memory address). A value of 0 or an
3984 omitted "align" argument means that the operation has the preferential
3985 alignment for the target. It is the responsibility of the code emitter to
3986 ensure that the alignment information is correct. Overestimating the
3987 alignment results in an undefined behavior. Underestimating the alignment may
3988 produce less efficient code. An alignment of 1 is always safe.</p>
3989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3991<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3992 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3993 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3994 does not exceed the minimum number of bytes needed to hold all bits of the
3995 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3996 writing a value of a type like <tt>i20</tt> with a size that is not an
3997 integral number of bytes, it is unspecified what happens to the extra bits
3998 that do not belong to the type, but they will typically be overwritten.</p>
3999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001<pre>
4002 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4003 store i32 3, i32* %ptr <i>; yields {void}</i>
4004 %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]4005</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4007</div>
4008
4009<!-- _______________________________________________________________________ -->
4010<div class="doc_subsubsection">
4011 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4012</div>
4013
4014<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4016<h5>Syntax:</h5>
4017<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4018 &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]4019 &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]4020</pre>
4021
4022<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4023<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4024 subelement of an aggregate data structure. It performs address calculation
4025 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026
4027<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4028<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4029 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4030 elements of the aggregate object are indexed. The interpretation of each
4031 index is dependent on the type being indexed into. The first index always
4032 indexes the pointer value given as the first argument, the second index
4033 indexes a value of the type pointed to (not necessarily the value directly
4034 pointed to, since the first index can be non-zero), etc. The first type
4035 indexed into must be a pointer value, subsequent types can be arrays, vectors
4036 and structs. Note that subsequent types being indexed into can never be
4037 pointers, since that would require loading the pointer before continuing
4038 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4039
4040<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]4041 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4042 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4043 vector, integers of any width are allowed, and they are not required to be
4044 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4045
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4046<p>For example, let's consider a C code fragment and how it gets compiled to
4047 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4048
4049<div class="doc_code">
4050<pre>
4051struct RT {
4052 char A;
4053 int B[10][20];
4054 char C;
4055};
4056struct ST {
4057 int X;
4058 double Y;
4059 struct RT Z;
4060};
4061
4062int *foo(struct ST *s) {
4063 return &amp;s[1].Z.B[5][13];
4064}
4065</pre>
4066</div>
4067
4068<p>The LLVM code generated by the GCC frontend is:</p>
4069
4070<div class="doc_code">
4071<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4072%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4073%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4075define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076entry:
4077 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4078 ret i32* %reg
4079}
4080</pre>
4081</div>
4082
4083<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084<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]4085 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4086 }</tt>' type, a structure. The second index indexes into the third element
4087 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4088 i8 }</tt>' type, another structure. The third index indexes into the second
4089 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4090 array. The two dimensions of the array are subscripted into, yielding an
4091 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4092 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4093
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4094<p>Note that it is perfectly legal to index partially through a structure,
4095 returning a pointer to an inner element. Because of this, the LLVM code for
4096 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4097
4098<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4099 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4100 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4101 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4102 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4103 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4104 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4105 ret i32* %t5
4106 }
4107</pre>
4108
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4109<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4110 <tt>getelementptr</tt> is undefined if the base pointer is not an
4111 <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]4112 that would be formed by successive addition of the offsets implied by the
4113 indices to the base address with infinitely precise arithmetic are not an
4114 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4115 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4116 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4117
4118<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4119 the base address with silently-wrapping two's complement arithmetic, and
4120 the result value of the <tt>getelementptr</tt> may be outside the object
4121 pointed to by the base pointer. The result value may not necessarily be
4122 used to access memory though, even if it happens to point into allocated
4123 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4124 section for more information.</p>
4125
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4126<p>The getelementptr instruction is often confusing. For some more insight into
4127 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4128
4129<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4130<pre>
4131 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4132 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4133 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4134 %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]4135 <i>; yields i8*:eptr</i>
4136 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4137 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4138 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4139</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4140
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141</div>
4142
4143<!-- ======================================================================= -->
4144<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4145</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4148
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4149<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4150 which all take a single operand and a type. They perform various bit
4151 conversions on the operand.</p>
4152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153</div>
4154
4155<!-- _______________________________________________________________________ -->
4156<div class="doc_subsubsection">
4157 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4158</div>
4159<div class="doc_text">
4160
4161<h5>Syntax:</h5>
4162<pre>
4163 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4164</pre>
4165
4166<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4167<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4168 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169
4170<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4171<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4172 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4173 size and type of the result, which must be
4174 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4175 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4176 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4177
4178<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4179<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4180 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4181 source size must be larger than the destination size, <tt>trunc</tt> cannot
4182 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4183
4184<h5>Example:</h5>
4185<pre>
4186 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4187 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
4188 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
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_subsubsection">
4195 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4196</div>
4197<div class="doc_text">
4198
4199<h5>Syntax:</h5>
4200<pre>
4201 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4202</pre>
4203
4204<h5>Overview:</h5>
4205<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4206 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4207
4208
4209<h5>Arguments:</h5>
4210<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]4211 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4212 also be of <a href="#t_integer">integer</a> type. The bit size of the
4213 <tt>value</tt> must be smaller than the bit size of the destination type,
4214 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4215
4216<h5>Semantics:</h5>
4217<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]4218 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4219
4220<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4221
4222<h5>Example:</h5>
4223<pre>
4224 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4225 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4226</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4228</div>
4229
4230<!-- _______________________________________________________________________ -->
4231<div class="doc_subsubsection">
4232 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4233</div>
4234<div class="doc_text">
4235
4236<h5>Syntax:</h5>
4237<pre>
4238 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4239</pre>
4240
4241<h5>Overview:</h5>
4242<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4243
4244<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4245<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4246 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4247 also be of <a href="#t_integer">integer</a> type. The bit size of the
4248 <tt>value</tt> must be smaller than the bit size of the destination type,
4249 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4250
4251<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4252<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4253 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4254 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255
4256<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4257
4258<h5>Example:</h5>
4259<pre>
4260 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4261 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4262</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264</div>
4265
4266<!-- _______________________________________________________________________ -->
4267<div class="doc_subsubsection">
4268 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4269</div>
4270
4271<div class="doc_text">
4272
4273<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4274<pre>
4275 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4276</pre>
4277
4278<h5>Overview:</h5>
4279<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4280 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4281
4282<h5>Arguments:</h5>
4283<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4284 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4285 to cast it to. The size of <tt>value</tt> must be larger than the size of
4286 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4287 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288
4289<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4290<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4291 <a href="#t_floating">floating point</a> type to a smaller
4292 <a href="#t_floating">floating point</a> type. If the value cannot fit
4293 within the destination type, <tt>ty2</tt>, then the results are
4294 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4295
4296<h5>Example:</h5>
4297<pre>
4298 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4299 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4300</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4302</div>
4303
4304<!-- _______________________________________________________________________ -->
4305<div class="doc_subsubsection">
4306 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4307</div>
4308<div class="doc_text">
4309
4310<h5>Syntax:</h5>
4311<pre>
4312 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4313</pre>
4314
4315<h5>Overview:</h5>
4316<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]4317 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4318
4319<h5>Arguments:</h5>
4320<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4322 a <a href="#t_floating">floating point</a> type to cast it to. The source
4323 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4324
4325<h5>Semantics:</h5>
4326<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4327 <a href="#t_floating">floating point</a> type to a larger
4328 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4329 used to make a <i>no-op cast</i> because it always changes bits. Use
4330 <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]4331
4332<h5>Example:</h5>
4333<pre>
4334 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4335 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4336</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4337
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4338</div>
4339
4340<!-- _______________________________________________________________________ -->
4341<div class="doc_subsubsection">
4342 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4343</div>
4344<div class="doc_text">
4345
4346<h5>Syntax:</h5>
4347<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4348 &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]4349</pre>
4350
4351<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4352<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4353 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354
4355<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4356<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4357 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4358 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4359 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4360 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4361
4362<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4363<p>The '<tt>fptoui</tt>' instruction converts its
4364 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4365 towards zero) unsigned integer value. If the value cannot fit
4366 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4368<h5>Example:</h5>
4369<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4370 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4371 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4372 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4373</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375</div>
4376
4377<!-- _______________________________________________________________________ -->
4378<div class="doc_subsubsection">
4379 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4380</div>
4381<div class="doc_text">
4382
4383<h5>Syntax:</h5>
4384<pre>
4385 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4386</pre>
4387
4388<h5>Overview:</h5>
4389<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4390 <a href="#t_floating">floating point</a> <tt>value</tt> to
4391 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4392
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4393<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4394<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4395 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4396 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4397 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4398 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4399
4400<h5>Semantics:</h5>
4401<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4402 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4403 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4404 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4406<h5>Example:</h5>
4407<pre>
4408 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4409 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4410 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4411</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413</div>
4414
4415<!-- _______________________________________________________________________ -->
4416<div class="doc_subsubsection">
4417 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4418</div>
4419<div class="doc_text">
4420
4421<h5>Syntax:</h5>
4422<pre>
4423 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4424</pre>
4425
4426<h5>Overview:</h5>
4427<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4428 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4431<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]4432 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4433 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4434 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4435 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4436
4437<h5>Semantics:</h5>
4438<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4439 integer quantity and converts it to the corresponding floating point
4440 value. If the value cannot fit in the floating point value, the results are
4441 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443<h5>Example:</h5>
4444<pre>
4445 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4446 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449</div>
4450
4451<!-- _______________________________________________________________________ -->
4452<div class="doc_subsubsection">
4453 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4454</div>
4455<div class="doc_text">
4456
4457<h5>Syntax:</h5>
4458<pre>
4459 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4460</pre>
4461
4462<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4463<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4464 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4465
4466<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4467<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]4468 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4469 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4470 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4471 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4472
4473<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4474<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4475 quantity and converts it to the corresponding floating point value. If the
4476 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477
4478<h5>Example:</h5>
4479<pre>
4480 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4481 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484</div>
4485
4486<!-- _______________________________________________________________________ -->
4487<div class="doc_subsubsection">
4488 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4489</div>
4490<div class="doc_text">
4491
4492<h5>Syntax:</h5>
4493<pre>
4494 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4495</pre>
4496
4497<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4498<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4499 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4500
4501<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4502<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4503 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4504 <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]4505
4506<h5>Semantics:</h5>
4507<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4508 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4509 truncating or zero extending that value to the size of the integer type. If
4510 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4511 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4512 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4513 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4514
4515<h5>Example:</h5>
4516<pre>
4517 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4518 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4519</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4521</div>
4522
4523<!-- _______________________________________________________________________ -->
4524<div class="doc_subsubsection">
4525 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4526</div>
4527<div class="doc_text">
4528
4529<h5>Syntax:</h5>
4530<pre>
4531 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4532</pre>
4533
4534<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4535<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4536 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4537
4538<h5>Arguments:</h5>
4539<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4540 value to cast, and a type to cast it to, which must be a
4541 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4542
4543<h5>Semantics:</h5>
4544<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4545 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4546 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4547 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4548 than the size of a pointer then a zero extension is done. If they are the
4549 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4550
4551<h5>Example:</h5>
4552<pre>
4553 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4554 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4555 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4556</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4558</div>
4559
4560<!-- _______________________________________________________________________ -->
4561<div class="doc_subsubsection">
4562 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4563</div>
4564<div class="doc_text">
4565
4566<h5>Syntax:</h5>
4567<pre>
4568 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4569</pre>
4570
4571<h5>Overview:</h5>
4572<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4573 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4574
4575<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4576<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4577 non-aggregate first class value, and a type to cast it to, which must also be
4578 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4579 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4580 identical. If the source type is a pointer, the destination type must also be
4581 a pointer. This instruction supports bitwise conversion of vectors to
4582 integers and to vectors of other types (as long as they have the same
4583 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584
4585<h5>Semantics:</h5>
4586<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4587 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4588 this conversion. The conversion is done as if the <tt>value</tt> had been
4589 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4590 be converted to other pointer types with this instruction. To convert
4591 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4592 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4593
4594<h5>Example:</h5>
4595<pre>
4596 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4597 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4598 %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]4599</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4601</div>
4602
4603<!-- ======================================================================= -->
4604<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4606<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4607
4608<p>The instructions in this category are the "miscellaneous" instructions, which
4609 defy better classification.</p>
4610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4611</div>
4612
4613<!-- _______________________________________________________________________ -->
4614<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4615</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4616
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4617<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4619<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4620<pre>
4621 &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]4622</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4625<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4626 boolean values based on comparison of its two integer, integer vector, or
4627 pointer operands.</p>
4628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4629<h5>Arguments:</h5>
4630<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4631 the condition code indicating the kind of comparison to perform. It is not a
4632 value, just a keyword. The possible condition code are:</p>
4633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4634<ol>
4635 <li><tt>eq</tt>: equal</li>
4636 <li><tt>ne</tt>: not equal </li>
4637 <li><tt>ugt</tt>: unsigned greater than</li>
4638 <li><tt>uge</tt>: unsigned greater or equal</li>
4639 <li><tt>ult</tt>: unsigned less than</li>
4640 <li><tt>ule</tt>: unsigned less or equal</li>
4641 <li><tt>sgt</tt>: signed greater than</li>
4642 <li><tt>sge</tt>: signed greater or equal</li>
4643 <li><tt>slt</tt>: signed less than</li>
4644 <li><tt>sle</tt>: signed less or equal</li>
4645</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4647<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4648 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4649 typed. They must also be identical types.</p>
4650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4652<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4653 condition code given as <tt>cond</tt>. The comparison performed always yields
4654 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4655 result, as follows:</p>
4656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4657<ol>
4658 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659 <tt>false</tt> otherwise. No sign interpretation is necessary or
4660 performed.</li>
4661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4662 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4663 <tt>false</tt> otherwise. No sign interpretation is necessary or
4664 performed.</li>
4665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4667 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4670 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4671 to <tt>op2</tt>.</li>
4672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4674 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4675
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4676 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4677 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4679 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4680 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4682 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4683 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4684 to <tt>op2</tt>.</li>
4685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4687 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4689 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4690 <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]4691</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4693<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4694 values are compared as if they were integers.</p>
4695
4696<p>If the operands are integer vectors, then they are compared element by
4697 element. The result is an <tt>i1</tt> vector with the same number of elements
4698 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4699
4700<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4701<pre>
4702 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4703 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4704 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4705 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4706 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4707 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4708</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4709
4710<p>Note that the code generator does not yet support vector types with
4711 the <tt>icmp</tt> instruction.</p>
4712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4713</div>
4714
4715<!-- _______________________________________________________________________ -->
4716<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4717</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4719<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4721<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4722<pre>
4723 &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]4724</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4728 values based on comparison of its operands.</p>
4729
4730<p>If the operands are floating point scalars, then the result type is a boolean
4731(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4732
4733<p>If the operands are floating point vectors, then the result type is a vector
4734 of boolean with the same number of elements as the operands being
4735 compared.</p>
4736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4737<h5>Arguments:</h5>
4738<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4739 the condition code indicating the kind of comparison to perform. It is not a
4740 value, just a keyword. The possible condition code are:</p>
4741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4742<ol>
4743 <li><tt>false</tt>: no comparison, always returns false</li>
4744 <li><tt>oeq</tt>: ordered and equal</li>
4745 <li><tt>ogt</tt>: ordered and greater than </li>
4746 <li><tt>oge</tt>: ordered and greater than or equal</li>
4747 <li><tt>olt</tt>: ordered and less than </li>
4748 <li><tt>ole</tt>: ordered and less than or equal</li>
4749 <li><tt>one</tt>: ordered and not equal</li>
4750 <li><tt>ord</tt>: ordered (no nans)</li>
4751 <li><tt>ueq</tt>: unordered or equal</li>
4752 <li><tt>ugt</tt>: unordered or greater than </li>
4753 <li><tt>uge</tt>: unordered or greater than or equal</li>
4754 <li><tt>ult</tt>: unordered or less than </li>
4755 <li><tt>ule</tt>: unordered or less than or equal</li>
4756 <li><tt>une</tt>: unordered or not equal</li>
4757 <li><tt>uno</tt>: unordered (either nans)</li>
4758 <li><tt>true</tt>: no comparison, always returns true</li>
4759</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4761<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762 <i>unordered</i> means that either operand may be a QNAN.</p>
4763
4764<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4765 a <a href="#t_floating">floating point</a> type or
4766 a <a href="#t_vector">vector</a> of floating point type. They must have
4767 identical types.</p>
4768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4769<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4770<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4771 according to the condition code given as <tt>cond</tt>. If the operands are
4772 vectors, then the vectors are compared element by element. Each comparison
4773 performed always yields an <a href="#t_primitive">i1</a> result, as
4774 follows:</p>
4775
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4776<ol>
4777 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4779 <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]4780 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4782 <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]4783 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4784
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4785 <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]4786 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4788 <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]4789 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4791 <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]4792 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4794 <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]4795 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4797 <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]4798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4799 <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]4800 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802 <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]4803 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4805 <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]4806 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4808 <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]4809 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4811 <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]4812 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4814 <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]4815 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4817 <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]4818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4819 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4820</ol>
4821
4822<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4823<pre>
4824 &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]4825 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4826 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4827 &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]4828</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4829
4830<p>Note that the code generator does not yet support vector types with
4831 the <tt>fcmp</tt> instruction.</p>
4832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4833</div>
4834
4835<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4836<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4837 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4838</div>
4839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4840<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4843<pre>
4844 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4845</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4848<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4849 SSA graph representing the function.</p>
4850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4851<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4852<p>The type of the incoming values is specified with the first type field. After
4853 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4854 one pair for each predecessor basic block of the current block. Only values
4855 of <a href="#t_firstclass">first class</a> type may be used as the value
4856 arguments to the PHI node. Only labels may be used as the label
4857 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4858
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4859<p>There must be no non-phi instructions between the start of a basic block and
4860 the PHI instructions: i.e. PHI instructions must be first in a basic
4861 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4862
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4863<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4864 occur on the edge from the corresponding predecessor block to the current
4865 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4866 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4868<h5>Semantics:</h5>
4869<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4870 specified by the pair corresponding to the predecessor basic block that
4871 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4873<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4874<pre>
4875Loop: ; Infinite loop that counts from 0 on up...
4876 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4877 %nextindvar = add i32 %indvar, 1
4878 br label %Loop
4879</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4881</div>
4882
4883<!-- _______________________________________________________________________ -->
4884<div class="doc_subsubsection">
4885 <a name="i_select">'<tt>select</tt>' Instruction</a>
4886</div>
4887
4888<div class="doc_text">
4889
4890<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4891<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4892 &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>
4893
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4894 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4895</pre>
4896
4897<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4898<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4899 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4900
4901
4902<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4903<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4904 values indicating the condition, and two values of the
4905 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4906 vectors and the condition is a scalar, then entire vectors are selected, not
4907 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4908
4909<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4910<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4911 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4912
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4913<p>If the condition is a vector of i1, then the value arguments must be vectors
4914 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4915
4916<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4917<pre>
4918 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4919</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4920
4921<p>Note that the code generator does not yet support conditions
4922 with vector type.</p>
4923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4924</div>
4925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4926<!-- _______________________________________________________________________ -->
4927<div class="doc_subsubsection">
4928 <a name="i_call">'<tt>call</tt>' Instruction</a>
4929</div>
4930
4931<div class="doc_text">
4932
4933<h5>Syntax:</h5>
4934<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4935 &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]4936</pre>
4937
4938<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4939<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4940
4941<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4942<p>This instruction requires several arguments:</p>
4943
4944<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4945 <li>The optional "tail" marker indicates whether the callee function accesses
4946 any allocas or varargs in the caller. If the "tail" marker is present,
4947 the function call is eligible for tail call optimization. Note that calls
4948 may be marked "tail" even if they do not occur before
4949 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4950
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4951 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4952 convention</a> the call should use. If none is specified, the call
4953 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4954
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4955 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4956 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4957 '<tt>inreg</tt>' attributes are valid here.</li>
4958
4959 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4960 type of the return value. Functions that return no value are marked
4961 <tt><a href="#t_void">void</a></tt>.</li>
4962
4963 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4964 being invoked. The argument types must match the types implied by this
4965 signature. This type can be omitted if the function is not varargs and if
4966 the function type does not return a pointer to a function.</li>
4967
4968 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4969 be invoked. In most cases, this is a direct function invocation, but
4970 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4971 to function value.</li>
4972
4973 <li>'<tt>function args</tt>': argument list whose types match the function
4974 signature argument types. All arguments must be of
4975 <a href="#t_firstclass">first class</a> type. If the function signature
4976 indicates the function accepts a variable number of arguments, the extra
4977 arguments can be specified.</li>
4978
4979 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4980 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4981 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4982</ol>
4983
4984<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4985<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4986 a specified function, with its incoming arguments bound to the specified
4987 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4988 function, control flow continues with the instruction after the function
4989 call, and the return value of the function is bound to the result
4990 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4991
4992<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4993<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4994 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4995 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4996 %X = tail call i32 @foo() <i>; yields i32</i>
4997 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4998 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4999
5000 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5001 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5002 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5003 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5004 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5005 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5006</pre>
5007
5008</div>
5009
5010<!-- _______________________________________________________________________ -->
5011<div class="doc_subsubsection">
5012 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5013</div>
5014
5015<div class="doc_text">
5016
5017<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5018<pre>
5019 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5020</pre>
5021
5022<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5023<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5024 the "variable argument" area of a function call. It is used to implement the
5025 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5026
5027<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5028<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5029 argument. It returns a value of the specified argument type and increments
5030 the <tt>va_list</tt> to point to the next argument. The actual type
5031 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032
5033<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5034<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5035 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5036 to the next argument. For more information, see the variable argument
5037 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5038
5039<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]5040 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5041 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5042
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5043<p><tt>va_arg</tt> is an LLVM instruction instead of
5044 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5045 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5046
5047<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5048<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5049
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5050<p>Note that the code generator does not yet fully support va_arg on many
5051 targets. Also, it does not currently support va_arg with aggregate types on
5052 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5054</div>
5055
5056<!-- *********************************************************************** -->
5057<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5058<!-- *********************************************************************** -->
5059
5060<div class="doc_text">
5061
5062<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5063 well known names and semantics and are required to follow certain
5064 restrictions. Overall, these intrinsics represent an extension mechanism for
5065 the LLVM language that does not require changing all of the transformations
5066 in LLVM when adding to the language (or the bitcode reader/writer, the
5067 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5068
5069<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5070 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5071 begin with this prefix. Intrinsic functions must always be external
5072 functions: you cannot define the body of intrinsic functions. Intrinsic
5073 functions may only be used in call or invoke instructions: it is illegal to
5074 take the address of an intrinsic function. Additionally, because intrinsic
5075 functions are part of the LLVM language, it is required if any are added that
5076 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5077
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5078<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5079 family of functions that perform the same operation but on different data
5080 types. Because LLVM can represent over 8 million different integer types,
5081 overloading is used commonly to allow an intrinsic function to operate on any
5082 integer type. One or more of the argument types or the result type can be
5083 overloaded to accept any integer type. Argument types may also be defined as
5084 exactly matching a previous argument's type or the result type. This allows
5085 an intrinsic function which accepts multiple arguments, but needs all of them
5086 to be of the same type, to only be overloaded with respect to a single
5087 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5089<p>Overloaded intrinsics will have the names of its overloaded argument types
5090 encoded into its function name, each preceded by a period. Only those types
5091 which are overloaded result in a name suffix. Arguments whose type is matched
5092 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5093 can take an integer of any width and returns an integer of exactly the same
5094 integer width. This leads to a family of functions such as
5095 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5096 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5097 suffix is required. Because the argument's type is matched against the return
5098 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5099
5100<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5101 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5102
5103</div>
5104
5105<!-- ======================================================================= -->
5106<div class="doc_subsection">
5107 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5108</div>
5109
5110<div class="doc_text">
5111
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5112<p>Variable argument support is defined in LLVM with
5113 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5114 intrinsic functions. These functions are related to the similarly named
5115 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5116
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5117<p>All of these functions operate on arguments that use a target-specific value
5118 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5119 not define what this type is, so all transformations should be prepared to
5120 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121
5122<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]5123 instruction and the variable argument handling intrinsic functions are
5124 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5125
5126<div class="doc_code">
5127<pre>
5128define i32 @test(i32 %X, ...) {
5129 ; Initialize variable argument processing
5130 %ap = alloca i8*
5131 %ap2 = bitcast i8** %ap to i8*
5132 call void @llvm.va_start(i8* %ap2)
5133
5134 ; Read a single integer argument
5135 %tmp = va_arg i8** %ap, i32
5136
5137 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5138 %aq = alloca i8*
5139 %aq2 = bitcast i8** %aq to i8*
5140 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5141 call void @llvm.va_end(i8* %aq2)
5142
5143 ; Stop processing of arguments.
5144 call void @llvm.va_end(i8* %ap2)
5145 ret i32 %tmp
5146}
5147
5148declare void @llvm.va_start(i8*)
5149declare void @llvm.va_copy(i8*, i8*)
5150declare void @llvm.va_end(i8*)
5151</pre>
5152</div>
5153
5154</div>
5155
5156<!-- _______________________________________________________________________ -->
5157<div class="doc_subsubsection">
5158 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5159</div>
5160
5161
5162<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5163
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5164<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5165<pre>
5166 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5167</pre>
5168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5169<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5170<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5171 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]5172
5173<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5174<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]5175
5176<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5177<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]5178 macro available in C. In a target-dependent way, it initializes
5179 the <tt>va_list</tt> element to which the argument points, so that the next
5180 call to <tt>va_arg</tt> will produce the first variable argument passed to
5181 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5182 need to know the last argument of the function as the compiler can figure
5183 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5184
5185</div>
5186
5187<!-- _______________________________________________________________________ -->
5188<div class="doc_subsubsection">
5189 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5190</div>
5191
5192<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5193
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5194<h5>Syntax:</h5>
5195<pre>
5196 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5197</pre>
5198
5199<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5200<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5201 which has been initialized previously
5202 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5203 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5204
5205<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5206<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5207
5208<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5209<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]5210 macro available in C. In a target-dependent way, it destroys
5211 the <tt>va_list</tt> element to which the argument points. Calls
5212 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5213 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5214 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5215
5216</div>
5217
5218<!-- _______________________________________________________________________ -->
5219<div class="doc_subsubsection">
5220 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5221</div>
5222
5223<div class="doc_text">
5224
5225<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5226<pre>
5227 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5228</pre>
5229
5230<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5231<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5232 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5233
5234<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5235<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]5236 The second argument is a pointer to a <tt>va_list</tt> element to copy
5237 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5238
5239<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240<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]5241 macro available in C. In a target-dependent way, it copies the
5242 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5243 element. This intrinsic is necessary because
5244 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5245 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5246
5247</div>
5248
5249<!-- ======================================================================= -->
5250<div class="doc_subsection">
5251 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5252</div>
5253
5254<div class="doc_text">
5255
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5256<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5257Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5258intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5259roots on the stack</a>, as well as garbage collector implementations that
5260require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5261barriers. Front-ends for type-safe garbage collected languages should generate
5262these intrinsics to make use of the LLVM garbage collectors. For more details,
5263see <a href="GarbageCollection.html">Accurate Garbage Collection with
5264LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5265
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5266<p>The garbage collection intrinsics only operate on objects in the generic
5267 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5268
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5269</div>
5270
5271<!-- _______________________________________________________________________ -->
5272<div class="doc_subsubsection">
5273 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5274</div>
5275
5276<div class="doc_text">
5277
5278<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5280 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5281</pre>
5282
5283<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5284<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]5285 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5286
5287<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5288<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5289 root pointer. The second pointer (which must be either a constant or a
5290 global value address) contains the meta-data to be associated with the
5291 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5292
5293<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5294<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]5295 location. At compile-time, the code generator generates information to allow
5296 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5297 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5298 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5299
5300</div>
5301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5302<!-- _______________________________________________________________________ -->
5303<div class="doc_subsubsection">
5304 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5305</div>
5306
5307<div class="doc_text">
5308
5309<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5311 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5312</pre>
5313
5314<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5315<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5316 locations, allowing garbage collector implementations that require read
5317 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318
5319<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5320<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]5321 allocated from the garbage collector. The first object is a pointer to the
5322 start of the referenced object, if needed by the language runtime (otherwise
5323 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5324
5325<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5326<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5327 instruction, but may be replaced with substantially more complex code by the
5328 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5329 may only be used in a function which <a href="#gc">specifies a GC
5330 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5331
5332</div>
5333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5334<!-- _______________________________________________________________________ -->
5335<div class="doc_subsubsection">
5336 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5337</div>
5338
5339<div class="doc_text">
5340
5341<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5343 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5344</pre>
5345
5346<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5347<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5348 locations, allowing garbage collector implementations that require write
5349 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5350
5351<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352<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]5353 object to store it to, and the third is the address of the field of Obj to
5354 store to. If the runtime does not require a pointer to the object, Obj may
5355 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5356
5357<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5359 instruction, but may be replaced with substantially more complex code by the
5360 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5361 may only be used in a function which <a href="#gc">specifies a GC
5362 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5363
5364</div>
5365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366<!-- ======================================================================= -->
5367<div class="doc_subsection">
5368 <a name="int_codegen">Code Generator Intrinsics</a>
5369</div>
5370
5371<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5372
5373<p>These intrinsics are provided by LLVM to expose special features that may
5374 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5375
5376</div>
5377
5378<!-- _______________________________________________________________________ -->
5379<div class="doc_subsubsection">
5380 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5381</div>
5382
5383<div class="doc_text">
5384
5385<h5>Syntax:</h5>
5386<pre>
5387 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5388</pre>
5389
5390<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5391<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5392 target-specific value indicating the return address of the current function
5393 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5394
5395<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5396<p>The argument to this intrinsic indicates which function to return the address
5397 for. Zero indicates the calling function, one indicates its caller, etc.
5398 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399
5400<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5401<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5402 indicating the return address of the specified call frame, or zero if it
5403 cannot be identified. The value returned by this intrinsic is likely to be
5404 incorrect or 0 for arguments other than zero, so it should only be used for
5405 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5407<p>Note that calling this intrinsic does not prevent function inlining or other
5408 aggressive transformations, so the value returned may not be that of the
5409 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5411</div>
5412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5413<!-- _______________________________________________________________________ -->
5414<div class="doc_subsubsection">
5415 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5416</div>
5417
5418<div class="doc_text">
5419
5420<h5>Syntax:</h5>
5421<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5422 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423</pre>
5424
5425<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5426<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5427 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5428
5429<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5430<p>The argument to this intrinsic indicates which function to return the frame
5431 pointer for. Zero indicates the calling function, one indicates its caller,
5432 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5433
5434<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5435<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5436 indicating the frame address of the specified call frame, or zero if it
5437 cannot be identified. The value returned by this intrinsic is likely to be
5438 incorrect or 0 for arguments other than zero, so it should only be used for
5439 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5440
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p>Note that calling this intrinsic does not prevent function inlining or other
5442 aggressive transformations, so the value returned may not be that of the
5443 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5445</div>
5446
5447<!-- _______________________________________________________________________ -->
5448<div class="doc_subsubsection">
5449 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5450</div>
5451
5452<div class="doc_text">
5453
5454<h5>Syntax:</h5>
5455<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5456 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5457</pre>
5458
5459<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5460<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5461 of the function stack, for use
5462 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5463 useful for implementing language features like scoped automatic variable
5464 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5465
5466<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5467<p>This intrinsic returns a opaque pointer value that can be passed
5468 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5469 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5470 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5471 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5472 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5473 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5474
5475</div>
5476
5477<!-- _______________________________________________________________________ -->
5478<div class="doc_subsubsection">
5479 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5480</div>
5481
5482<div class="doc_text">
5483
5484<h5>Syntax:</h5>
5485<pre>
5486 declare void @llvm.stackrestore(i8 * %ptr)
5487</pre>
5488
5489<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5490<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5491 the function stack to the state it was in when the
5492 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5493 executed. This is useful for implementing language features like scoped
5494 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5495
5496<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5497<p>See the description
5498 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5499
5500</div>
5501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5502<!-- _______________________________________________________________________ -->
5503<div class="doc_subsubsection">
5504 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5505</div>
5506
5507<div class="doc_text">
5508
5509<h5>Syntax:</h5>
5510<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5511 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]5512</pre>
5513
5514<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5515<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5516 insert a prefetch instruction if supported; otherwise, it is a noop.
5517 Prefetches have no effect on the behavior of the program but can change its
5518 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519
5520<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5521<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5522 specifier determining if the fetch should be for a read (0) or write (1),
5523 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5524 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5525 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5526
5527<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5528<p>This intrinsic does not modify the behavior of the program. In particular,
5529 prefetches cannot trap and do not produce a value. On targets that support
5530 this intrinsic, the prefetch can provide hints to the processor cache for
5531 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5532
5533</div>
5534
5535<!-- _______________________________________________________________________ -->
5536<div class="doc_subsubsection">
5537 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5538</div>
5539
5540<div class="doc_text">
5541
5542<h5>Syntax:</h5>
5543<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5544 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5545</pre>
5546
5547<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5548<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5549 Counter (PC) in a region of code to simulators and other tools. The method
5550 is target specific, but it is expected that the marker will use exported
5551 symbols to transmit the PC of the marker. The marker makes no guarantees
5552 that it will remain with any specific instruction after optimizations. It is
5553 possible that the presence of a marker will inhibit optimizations. The
5554 intended use is to be inserted after optimizations to allow correlations of
5555 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5556
5557<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5558<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5559
5560<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5561<p>This intrinsic does not modify the behavior of the program. Backends that do
5562 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5563
5564</div>
5565
5566<!-- _______________________________________________________________________ -->
5567<div class="doc_subsubsection">
5568 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5569</div>
5570
5571<div class="doc_text">
5572
5573<h5>Syntax:</h5>
5574<pre>
5575 declare i64 @llvm.readcyclecounter( )
5576</pre>
5577
5578<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5579<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5580 counter register (or similar low latency, high accuracy clocks) on those
5581 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5582 should map to RPCC. As the backing counters overflow quickly (on the order
5583 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5584
5585<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5586<p>When directly supported, reading the cycle counter should not modify any
5587 memory. Implementations are allowed to either return a application specific
5588 value or a system wide value. On backends without support, this is lowered
5589 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5590
5591</div>
5592
5593<!-- ======================================================================= -->
5594<div class="doc_subsection">
5595 <a name="int_libc">Standard C Library Intrinsics</a>
5596</div>
5597
5598<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5599
5600<p>LLVM provides intrinsics for a few important standard C library functions.
5601 These intrinsics allow source-language front-ends to pass information about
5602 the alignment of the pointer arguments to the code generator, providing
5603 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5604
5605</div>
5606
5607<!-- _______________________________________________________________________ -->
5608<div class="doc_subsubsection">
5609 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5610</div>
5611
5612<div class="doc_text">
5613
5614<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5615<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5616 integer bit width. Not all targets support all bit widths however.</p>
5617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5618<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5619 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5620 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5621 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5622 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5623 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5624 i32 &lt;len&gt;, i32 &lt;align&gt;)
5625 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5626 i64 &lt;len&gt;, i32 &lt;align&gt;)
5627</pre>
5628
5629<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5630<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5631 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5632
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5633<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5634 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635
5636<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5637<p>The first argument is a pointer to the destination, the second is a pointer
5638 to the source. The third argument is an integer argument specifying the
5639 number of bytes to copy, and the fourth argument is the alignment of the
5640 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5641
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5642<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5643 then the caller guarantees that both the source and destination pointers are
5644 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5645
5646<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5647<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5648 source location to the destination location, which are not allowed to
5649 overlap. It copies "len" bytes of memory over. If the argument is known to
5650 be aligned to some boundary, this can be specified as the fourth argument,
5651 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5653</div>
5654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5655<!-- _______________________________________________________________________ -->
5656<div class="doc_subsubsection">
5657 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5658</div>
5659
5660<div class="doc_text">
5661
5662<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5663<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]5664 width. Not all targets support all bit widths however.</p>
5665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5667 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5668 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5669 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5670 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5671 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5672 i32 &lt;len&gt;, i32 &lt;align&gt;)
5673 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5674 i64 &lt;len&gt;, i32 &lt;align&gt;)
5675</pre>
5676
5677<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5678<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5679 source location to the destination location. It is similar to the
5680 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5681 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5682
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5683<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5684 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The first argument is a pointer to the destination, the second is a pointer
5688 to the source. The third argument is an integer argument specifying the
5689 number of bytes to copy, and the fourth argument is the alignment of the
5690 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5691
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5692<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5693 then the caller guarantees that the source and destination pointers are
5694 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695
5696<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5697<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5698 source location to the destination location, which may overlap. It copies
5699 "len" bytes of memory over. If the argument is known to be aligned to some
5700 boundary, this can be specified as the fourth argument, otherwise it should
5701 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5703</div>
5704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
5707 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5713<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]5714 width. Not all targets support all bit widths however.</p>
5715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5717 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5719 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5720 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5721 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5722 i32 &lt;len&gt;, i32 &lt;align&gt;)
5723 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5724 i64 &lt;len&gt;, i32 &lt;align&gt;)
5725</pre>
5726
5727<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5728<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5729 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5730
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5731<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5732 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5733
5734<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5735<p>The first argument is a pointer to the destination to fill, the second is the
5736 byte value to fill it with, the third argument is an integer argument
5737 specifying the number of bytes to fill, and the fourth argument is the known
5738 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5739
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5740<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5741 then the caller guarantees that the destination pointer is aligned to that
5742 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5743
5744<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5745<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5746 at the destination location. If the argument is known to be aligned to some
5747 boundary, this can be specified as the fourth argument, otherwise it should
5748 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5750</div>
5751
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752<!-- _______________________________________________________________________ -->
5753<div class="doc_subsubsection">
5754 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5755</div>
5756
5757<div class="doc_text">
5758
5759<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5760<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5761 floating point or vector of floating point type. Not all targets support all
5762 types however.</p>
5763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5764<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5765 declare float @llvm.sqrt.f32(float %Val)
5766 declare double @llvm.sqrt.f64(double %Val)
5767 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5768 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5769 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5770</pre>
5771
5772<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5773<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5774 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5775 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5776 behavior for negative numbers other than -0.0 (which allows for better
5777 optimization, because there is no need to worry about errno being
5778 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]5779
5780<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5781<p>The argument and return value are floating point numbers of the same
5782 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783
5784<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5785<p>This function returns the sqrt of the specified operand if it is a
5786 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5788</div>
5789
5790<!-- _______________________________________________________________________ -->
5791<div class="doc_subsubsection">
5792 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5793</div>
5794
5795<div class="doc_text">
5796
5797<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5798<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5799 floating point or vector of floating point type. Not all targets support all
5800 types however.</p>
5801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5802<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5803 declare float @llvm.powi.f32(float %Val, i32 %power)
5804 declare double @llvm.powi.f64(double %Val, i32 %power)
5805 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5806 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5807 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5808</pre>
5809
5810<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5811<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5812 specified (positive or negative) power. The order of evaluation of
5813 multiplications is not defined. When a vector of floating point type is
5814 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5815
5816<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5817<p>The second argument is an integer power, and the first is a value to raise to
5818 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5819
5820<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5821<p>This function returns the first value raised to the second power with an
5822 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5824</div>
5825
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
5828 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5834<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5835 floating point or vector of floating point type. Not all targets support all
5836 types however.</p>
5837
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5838<pre>
5839 declare float @llvm.sin.f32(float %Val)
5840 declare double @llvm.sin.f64(double %Val)
5841 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5842 declare fp128 @llvm.sin.f128(fp128 %Val)
5843 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5844</pre>
5845
5846<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5848
5849<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5850<p>The argument and return value are floating point numbers of the same
5851 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5852
5853<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5854<p>This function returns the sine of the specified operand, returning the same
5855 values as the libm <tt>sin</tt> functions would, and handles error conditions
5856 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5857
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5858</div>
5859
5860<!-- _______________________________________________________________________ -->
5861<div class="doc_subsubsection">
5862 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5863</div>
5864
5865<div class="doc_text">
5866
5867<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5868<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5869 floating point or vector of floating point type. Not all targets support all
5870 types however.</p>
5871
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5872<pre>
5873 declare float @llvm.cos.f32(float %Val)
5874 declare double @llvm.cos.f64(double %Val)
5875 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5876 declare fp128 @llvm.cos.f128(fp128 %Val)
5877 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5878</pre>
5879
5880<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5882
5883<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5884<p>The argument and return value are floating point numbers of the same
5885 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5886
5887<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5888<p>This function returns the cosine of the specified operand, returning the same
5889 values as the libm <tt>cos</tt> functions would, and handles error conditions
5890 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5891
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5892</div>
5893
5894<!-- _______________________________________________________________________ -->
5895<div class="doc_subsubsection">
5896 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5897</div>
5898
5899<div class="doc_text">
5900
5901<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5902<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5903 floating point or vector of floating point type. Not all targets support all
5904 types however.</p>
5905
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5906<pre>
5907 declare float @llvm.pow.f32(float %Val, float %Power)
5908 declare double @llvm.pow.f64(double %Val, double %Power)
5909 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5910 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5911 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5912</pre>
5913
5914<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5915<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5916 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5917
5918<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5919<p>The second argument is a floating point power, and the first is a value to
5920 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5921
5922<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5923<p>This function returns the first value raised to the second power, returning
5924 the same values as the libm <tt>pow</tt> functions would, and handles error
5925 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5926
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5927</div>
5928
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5929<!-- ======================================================================= -->
5930<div class="doc_subsection">
5931 <a name="int_manip">Bit Manipulation Intrinsics</a>
5932</div>
5933
5934<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5935
5936<p>LLVM provides intrinsics for a few important bit manipulation operations.
5937 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5938
5939</div>
5940
5941<!-- _______________________________________________________________________ -->
5942<div class="doc_subsubsection">
5943 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5944</div>
5945
5946<div class="doc_text">
5947
5948<h5>Syntax:</h5>
5949<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5950 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5952<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5953 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5954 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5955 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5956</pre>
5957
5958<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5959<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5960 values with an even number of bytes (positive multiple of 16 bits). These
5961 are useful for performing operations on data that is not in the target's
5962 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5963
5964<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5965<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5966 and low byte of the input i16 swapped. Similarly,
5967 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5968 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5969 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5970 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5971 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5972 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5973
5974</div>
5975
5976<!-- _______________________________________________________________________ -->
5977<div class="doc_subsubsection">
5978 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5979</div>
5980
5981<div class="doc_text">
5982
5983<h5>Syntax:</h5>
5984<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]5985 width. Not all targets support all bit widths however.</p>
5986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5987<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5988 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5989 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5990 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5991 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5992 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5993</pre>
5994
5995<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5996<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5997 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5998
5999<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6000<p>The only argument is the value to be counted. The argument may be of any
6001 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6004<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]6005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6006</div>
6007
6008<!-- _______________________________________________________________________ -->
6009<div class="doc_subsubsection">
6010 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6011</div>
6012
6013<div class="doc_text">
6014
6015<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6016<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6017 integer bit width. Not all targets support all bit widths however.</p>
6018
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6019<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6020 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6021 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6022 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6023 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6024 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6025</pre>
6026
6027<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6028<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6029 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030
6031<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6032<p>The only argument is the value to be counted. The argument may be of any
6033 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6034
6035<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6036<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6037 zeros in a variable. If the src == 0 then the result is the size in bits of
6038 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6040</div>
6041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6042<!-- _______________________________________________________________________ -->
6043<div class="doc_subsubsection">
6044 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6045</div>
6046
6047<div class="doc_text">
6048
6049<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6050<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6051 integer bit width. Not all targets support all bit widths however.</p>
6052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6053<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6054 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6055 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6056 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6057 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6058 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6059</pre>
6060
6061<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6062<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6063 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6064
6065<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6066<p>The only argument is the value to be counted. The argument may be of any
6067 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6068
6069<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6071 zeros in a variable. If the src == 0 then the result is the size in bits of
6072 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6073
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6074</div>
6075
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6076<!-- ======================================================================= -->
6077<div class="doc_subsection">
6078 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6079</div>
6080
6081<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6082
6083<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6084
6085</div>
6086
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6087<!-- _______________________________________________________________________ -->
6088<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6089 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6090</div>
6091
6092<div class="doc_text">
6093
6094<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6095<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]6096 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6097
6098<pre>
6099 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6100 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6101 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6102</pre>
6103
6104<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6105<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6106 a signed addition of the two arguments, and indicate whether an overflow
6107 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6108
6109<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6110<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]6111 be of integer types of any bit width, but they must have the same bit
6112 width. The second element of the result structure must be of
6113 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6114 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6115
6116<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6117<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6118 a signed addition of the two variables. They return a structure &mdash; the
6119 first element of which is the signed summation, and the second element of
6120 which is a bit specifying if the signed summation resulted in an
6121 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6122
6123<h5>Examples:</h5>
6124<pre>
6125 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6126 %sum = extractvalue {i32, i1} %res, 0
6127 %obit = extractvalue {i32, i1} %res, 1
6128 br i1 %obit, label %overflow, label %normal
6129</pre>
6130
6131</div>
6132
6133<!-- _______________________________________________________________________ -->
6134<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6135 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6136</div>
6137
6138<div class="doc_text">
6139
6140<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6141<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]6142 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6143
6144<pre>
6145 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6146 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6147 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6148</pre>
6149
6150<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6151<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6152 an unsigned addition of the two arguments, and indicate whether a carry
6153 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6154
6155<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6156<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]6157 be of integer types of any bit width, but they must have the same bit
6158 width. The second element of the result structure must be of
6159 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6160 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6161
6162<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6163<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6164 an unsigned addition of the two arguments. They return a structure &mdash;
6165 the first element of which is the sum, and the second element of which is a
6166 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6167
6168<h5>Examples:</h5>
6169<pre>
6170 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6171 %sum = extractvalue {i32, i1} %res, 0
6172 %obit = extractvalue {i32, i1} %res, 1
6173 br i1 %obit, label %carry, label %normal
6174</pre>
6175
6176</div>
6177
6178<!-- _______________________________________________________________________ -->
6179<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6180 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6181</div>
6182
6183<div class="doc_text">
6184
6185<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6186<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]6187 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6188
6189<pre>
6190 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6191 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6192 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6193</pre>
6194
6195<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6196<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6197 a signed subtraction of the two arguments, and indicate whether an overflow
6198 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6199
6200<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6201<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]6202 be of integer types of any bit width, but they must have the same bit
6203 width. The second element of the result structure must be of
6204 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6205 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6206
6207<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6208<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6209 a signed subtraction of the two arguments. They return a structure &mdash;
6210 the first element of which is the subtraction, and the second element of
6211 which is a bit specifying if the signed subtraction resulted in an
6212 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6213
6214<h5>Examples:</h5>
6215<pre>
6216 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6217 %sum = extractvalue {i32, i1} %res, 0
6218 %obit = extractvalue {i32, i1} %res, 1
6219 br i1 %obit, label %overflow, label %normal
6220</pre>
6221
6222</div>
6223
6224<!-- _______________________________________________________________________ -->
6225<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6226 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6227</div>
6228
6229<div class="doc_text">
6230
6231<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6232<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]6233 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6234
6235<pre>
6236 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6237 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6238 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6239</pre>
6240
6241<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6242<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6243 an unsigned subtraction of the two arguments, and indicate whether an
6244 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6245
6246<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6247<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]6248 be of integer types of any bit width, but they must have the same bit
6249 width. The second element of the result structure must be of
6250 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6251 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6252
6253<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6254<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6255 an unsigned subtraction of the two arguments. They return a structure &mdash;
6256 the first element of which is the subtraction, and the second element of
6257 which is a bit specifying if the unsigned subtraction resulted in an
6258 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6259
6260<h5>Examples:</h5>
6261<pre>
6262 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6263 %sum = extractvalue {i32, i1} %res, 0
6264 %obit = extractvalue {i32, i1} %res, 1
6265 br i1 %obit, label %overflow, label %normal
6266</pre>
6267
6268</div>
6269
6270<!-- _______________________________________________________________________ -->
6271<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6272 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6273</div>
6274
6275<div class="doc_text">
6276
6277<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6278<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]6279 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6280
6281<pre>
6282 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6283 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6284 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6285</pre>
6286
6287<h5>Overview:</h5>
6288
6289<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6290 a signed multiplication of the two arguments, and indicate whether an
6291 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6292
6293<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6294<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]6295 be of integer types of any bit width, but they must have the same bit
6296 width. The second element of the result structure must be of
6297 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6298 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6299
6300<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6301<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6302 a signed multiplication of the two arguments. They return a structure &mdash;
6303 the first element of which is the multiplication, and the second element of
6304 which is a bit specifying if the signed multiplication resulted in an
6305 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6306
6307<h5>Examples:</h5>
6308<pre>
6309 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6310 %sum = extractvalue {i32, i1} %res, 0
6311 %obit = extractvalue {i32, i1} %res, 1
6312 br i1 %obit, label %overflow, label %normal
6313</pre>
6314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6315</div>
6316
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6317<!-- _______________________________________________________________________ -->
6318<div class="doc_subsubsection">
6319 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6320</div>
6321
6322<div class="doc_text">
6323
6324<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6325<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]6326 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6327
6328<pre>
6329 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6330 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6331 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6332</pre>
6333
6334<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6335<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6336 a unsigned multiplication of the two arguments, and indicate whether an
6337 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6338
6339<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6340<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]6341 be of integer types of any bit width, but they must have the same bit
6342 width. The second element of the result structure must be of
6343 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6344 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6345
6346<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6347<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6348 an unsigned multiplication of the two arguments. They return a structure
6349 &mdash; the first element of which is the multiplication, and the second
6350 element of which is a bit specifying if the unsigned multiplication resulted
6351 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6352
6353<h5>Examples:</h5>
6354<pre>
6355 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6356 %sum = extractvalue {i32, i1} %res, 0
6357 %obit = extractvalue {i32, i1} %res, 1
6358 br i1 %obit, label %overflow, label %normal
6359</pre>
6360
6361</div>
6362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6363<!-- ======================================================================= -->
6364<div class="doc_subsection">
6365 <a name="int_debugger">Debugger Intrinsics</a>
6366</div>
6367
6368<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6369
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6370<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6371 prefix), are described in
6372 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6373 Level Debugging</a> document.</p>
6374
6375</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6376
6377<!-- ======================================================================= -->
6378<div class="doc_subsection">
6379 <a name="int_eh">Exception Handling Intrinsics</a>
6380</div>
6381
6382<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6383
6384<p>The LLVM exception handling intrinsics (which all start with
6385 <tt>llvm.eh.</tt> prefix), are described in
6386 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6387 Handling</a> document.</p>
6388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6389</div>
6390
6391<!-- ======================================================================= -->
6392<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6393 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6394</div>
6395
6396<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6397
6398<p>This intrinsic makes it possible to excise one parameter, marked with
6399 the <tt>nest</tt> attribute, from a function. The result is a callable
6400 function pointer lacking the nest parameter - the caller does not need to
6401 provide a value for it. Instead, the value to use is stored in advance in a
6402 "trampoline", a block of memory usually allocated on the stack, which also
6403 contains code to splice the nest value into the argument list. This is used
6404 to implement the GCC nested function address extension.</p>
6405
6406<p>For example, if the function is
6407 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6408 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6409 follows:</p>
6410
6411<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6412<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6413 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6414 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6415 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6416 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6417</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6418</div>
6419
6420<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6421 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6422
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6423</div>
6424
6425<!-- _______________________________________________________________________ -->
6426<div class="doc_subsubsection">
6427 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6428</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6429
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6430<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6431
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6432<h5>Syntax:</h5>
6433<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6434 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]6435</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6436
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6437<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6438<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6439 function pointer suitable for executing it.</p>
6440
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6441<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6442<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6443 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6444 sufficiently aligned block of memory; this memory is written to by the
6445 intrinsic. Note that the size and the alignment are target-specific - LLVM
6446 currently provides no portable way of determining them, so a front-end that
6447 generates this intrinsic needs to have some target-specific knowledge.
6448 The <tt>func</tt> argument must hold a function bitcast to
6449 an <tt>i8*</tt>.</p>
6450
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6451<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6452<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6453 dependent code, turning it into a function. A pointer to this function is
6454 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6455 function pointer type</a> before being called. The new function's signature
6456 is the same as that of <tt>func</tt> with any arguments marked with
6457 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6458 is allowed, and it must be of pointer type. Calling the new function is
6459 equivalent to calling <tt>func</tt> with the same argument list, but
6460 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6461 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6462 by <tt>tramp</tt> is modified, then the effect of any later call to the
6463 returned function pointer is undefined.</p>
6464
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6465</div>
6466
6467<!-- ======================================================================= -->
6468<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6469 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6470</div>
6471
6472<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6473
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6474<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6475 hardware constructs for atomic operations and memory synchronization. This
6476 provides an interface to the hardware, not an interface to the programmer. It
6477 is aimed at a low enough level to allow any programming models or APIs
6478 (Application Programming Interfaces) which need atomic behaviors to map
6479 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6480 hardware provides a "universal IR" for source languages, it also provides a
6481 starting point for developing a "universal" atomic operation and
6482 synchronization IR.</p>
6483
6484<p>These do <em>not</em> form an API such as high-level threading libraries,
6485 software transaction memory systems, atomic primitives, and intrinsic
6486 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6487 application libraries. The hardware interface provided by LLVM should allow
6488 a clean implementation of all of these APIs and parallel programming models.
6489 No one model or paradigm should be selected above others unless the hardware
6490 itself ubiquitously does so.</p>
6491
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6492</div>
6493
6494<!-- _______________________________________________________________________ -->
6495<div class="doc_subsubsection">
6496 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6497</div>
6498<div class="doc_text">
6499<h5>Syntax:</h5>
6500<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6501 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]6502</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6503
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6504<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6505<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6506 specific pairs of memory access types.</p>
6507
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6508<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6509<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6510 The first four arguments enables a specific barrier as listed below. The
6511 fith argument specifies that the barrier applies to io or device or uncached
6512 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6513
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6514<ul>
6515 <li><tt>ll</tt>: load-load barrier</li>
6516 <li><tt>ls</tt>: load-store barrier</li>
6517 <li><tt>sl</tt>: store-load barrier</li>
6518 <li><tt>ss</tt>: store-store barrier</li>
6519 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6520</ul>
6521
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6522<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6523<p>This intrinsic causes the system to enforce some ordering constraints upon
6524 the loads and stores of the program. This barrier does not
6525 indicate <em>when</em> any events will occur, it only enforces
6526 an <em>order</em> in which they occur. For any of the specified pairs of load
6527 and store operations (f.ex. load-load, or store-load), all of the first
6528 operations preceding the barrier will complete before any of the second
6529 operations succeeding the barrier begin. Specifically the semantics for each
6530 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6531
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6532<ul>
6533 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6534 after the barrier begins.</li>
6535 <li><tt>ls</tt>: All loads before the barrier must complete before any
6536 store after the barrier begins.</li>
6537 <li><tt>ss</tt>: All stores before the barrier must complete before any
6538 store after the barrier begins.</li>
6539 <li><tt>sl</tt>: All stores before the barrier must complete before any
6540 load after the barrier begins.</li>
6541</ul>
6542
6543<p>These semantics are applied with a logical "and" behavior when more than one
6544 is enabled in a single memory barrier intrinsic.</p>
6545
6546<p>Backends may implement stronger barriers than those requested when they do
6547 not support as fine grained a barrier as requested. Some architectures do
6548 not need all types of barriers and on such architectures, these become
6549 noops.</p>
6550
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6551<h5>Example:</h5>
6552<pre>
6553%ptr = malloc i32
6554 store i32 4, %ptr
6555
6556%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6557 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6558 <i>; guarantee the above finishes</i>
6559 store i32 8, %ptr <i>; before this begins</i>
6560</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6561
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6562</div>
6563
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6564<!-- _______________________________________________________________________ -->
6565<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6566 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6567</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6568
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6569<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6570
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6571<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6572<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6573 any integer bit width and for different address spaces. Not all targets
6574 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6575
6576<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6577 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6578 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6579 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6580 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]6581</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6582
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6583<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6584<p>This loads a value in memory and compares it to a given value. If they are
6585 equal, it stores a new value into the memory.</p>
6586
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6587<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6588<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6589 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6590 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6591 this integer type. While any bit width integer may be used, targets may only
6592 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6593
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6594<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6595<p>This entire intrinsic must be executed atomically. It first loads the value
6596 in memory pointed to by <tt>ptr</tt> and compares it with the
6597 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6598 memory. The loaded value is yielded in all cases. This provides the
6599 equivalent of an atomic compare-and-swap operation within the SSA
6600 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6601
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6602<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6603<pre>
6604%ptr = malloc i32
6605 store i32 4, %ptr
6606
6607%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6608%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6609 <i>; yields {i32}:result1 = 4</i>
6610%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6611%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6612
6613%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6614%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6615 <i>; yields {i32}:result2 = 8</i>
6616%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6617
6618%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6619</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6620
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6621</div>
6622
6623<!-- _______________________________________________________________________ -->
6624<div class="doc_subsubsection">
6625 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6626</div>
6627<div class="doc_text">
6628<h5>Syntax:</h5>
6629
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6630<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6631 integer bit width. Not all targets support all bit widths however.</p>
6632
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6633<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6634 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6635 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6636 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6637 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]6638</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6639
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6640<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6641<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6642 the value from memory. It then stores the value in <tt>val</tt> in the memory
6643 at <tt>ptr</tt>.</p>
6644
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6645<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6646<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6647 the <tt>val</tt> argument and the result must be integers of the same bit
6648 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6649 integer type. The targets may only lower integer representations they
6650 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6651
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6652<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6653<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6654 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6655 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6656
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6657<h5>Examples:</h5>
6658<pre>
6659%ptr = malloc i32
6660 store i32 4, %ptr
6661
6662%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6663%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6664 <i>; yields {i32}:result1 = 4</i>
6665%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6666%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6667
6668%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6669%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6670 <i>; yields {i32}:result2 = 8</i>
6671
6672%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6673%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6674</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6675
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6676</div>
6677
6678<!-- _______________________________________________________________________ -->
6679<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6680 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6681
6682</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6683
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6684<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6685
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6686<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6687<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6688 any integer bit width. Not all targets support all bit widths however.</p>
6689
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6690<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6691 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6692 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6693 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6694 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]6695</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6696
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6697<h5>Overview:</h5>
6698<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6699 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6700
6701<h5>Arguments:</h5>
6702<p>The intrinsic takes two arguments, the first a pointer to an integer value
6703 and the second an integer value. The result is also an integer value. These
6704 integer types can have any bit width, but they must all have the same bit
6705 width. The targets may only lower integer representations they support.</p>
6706
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6707<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6708<p>This intrinsic does a series of operations atomically. It first loads the
6709 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6710 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]6711
6712<h5>Examples:</h5>
6713<pre>
6714%ptr = malloc i32
6715 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6716%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6717 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6718%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6719 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6720%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6721 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6722%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6723</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6724
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6725</div>
6726
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6727<!-- _______________________________________________________________________ -->
6728<div class="doc_subsubsection">
6729 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6730
6731</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6732
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6733<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6734
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6735<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6736<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6737 any integer bit width and for different address spaces. Not all targets
6738 support all bit widths however.</p>
6739
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6740<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6741 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6742 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6743 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6744 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]6745</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6746
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6747<h5>Overview:</h5>
6748<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6749 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6750
6751<h5>Arguments:</h5>
6752<p>The intrinsic takes two arguments, the first a pointer to an integer value
6753 and the second an integer value. The result is also an integer value. These
6754 integer types can have any bit width, but they must all have the same bit
6755 width. The targets may only lower integer representations they support.</p>
6756
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6757<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6758<p>This intrinsic does a series of operations atomically. It first loads the
6759 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6760 result to <tt>ptr</tt>. It yields the original value stored
6761 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6762
6763<h5>Examples:</h5>
6764<pre>
6765%ptr = malloc i32
6766 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6767%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6768 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6769%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6770 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6771%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6772 <i>; yields {i32}:result3 = 2</i>
6773%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6774</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6775
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6776</div>
6777
6778<!-- _______________________________________________________________________ -->
6779<div class="doc_subsubsection">
6780 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6781 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6782 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6783 <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]6784</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6785
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6786<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6787
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6788<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6789<p>These are overloaded intrinsics. You can
6790 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6791 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6792 bit width and for different address spaces. Not all targets support all bit
6793 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6794
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6795<pre>
6796 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6797 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6798 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6799 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]6800</pre>
6801
6802<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6803 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6804 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6805 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6806 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]6807</pre>
6808
6809<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6810 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6811 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6812 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6813 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]6814</pre>
6815
6816<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6817 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6818 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6819 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6820 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]6821</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6822
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6823<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6824<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6825 the value stored in memory at <tt>ptr</tt>. It yields the original value
6826 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6827
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6828<h5>Arguments:</h5>
6829<p>These intrinsics take two arguments, the first a pointer to an integer value
6830 and the second an integer value. The result is also an integer value. These
6831 integer types can have any bit width, but they must all have the same bit
6832 width. The targets may only lower integer representations they support.</p>
6833
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6834<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6835<p>These intrinsics does a series of operations atomically. They first load the
6836 value stored at <tt>ptr</tt>. They then do the bitwise
6837 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6838 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6839
6840<h5>Examples:</h5>
6841<pre>
6842%ptr = malloc i32
6843 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6844%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6845 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6846%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6847 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6848%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6849 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6850%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6851 <i>; yields {i32}:result3 = FF</i>
6852%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6853</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6854
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6855</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6856
6857<!-- _______________________________________________________________________ -->
6858<div class="doc_subsubsection">
6859 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6860 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6861 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6862 <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]6863</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6864
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6865<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6866
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6867<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6868<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6869 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6870 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6871 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6872
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6873<pre>
6874 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6875 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6876 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6877 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]6878</pre>
6879
6880<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6881 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6882 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6883 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6884 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]6885</pre>
6886
6887<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6888 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6889 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6890 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6891 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]6892</pre>
6893
6894<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6895 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6896 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6897 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6898 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]6899</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6900
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6901<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6902<p>These intrinsics takes the signed or unsigned minimum or maximum of
6903 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6904 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6905
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6906<h5>Arguments:</h5>
6907<p>These intrinsics take two arguments, the first a pointer to an integer value
6908 and the second an integer value. The result is also an integer value. These
6909 integer types can have any bit width, but they must all have the same bit
6910 width. The targets may only lower integer representations they support.</p>
6911
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6912<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6913<p>These intrinsics does a series of operations atomically. They first load the
6914 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6915 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6916 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6917
6918<h5>Examples:</h5>
6919<pre>
6920%ptr = malloc i32
6921 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6922%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6923 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6924%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6925 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6926%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6927 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6928%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6929 <i>; yields {i32}:result3 = 8</i>
6930%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6931</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6932
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6933</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6934
6935<!-- ======================================================================= -->
6936<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6937 <a name="int_general">General Intrinsics</a>
6938</div>
6939
6940<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6941
6942<p>This class of intrinsics is designed to be generic and has no specific
6943 purpose.</p>
6944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6945</div>
6946
6947<!-- _______________________________________________________________________ -->
6948<div class="doc_subsubsection">
6949 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6950</div>
6951
6952<div class="doc_text">
6953
6954<h5>Syntax:</h5>
6955<pre>
6956 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6957</pre>
6958
6959<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6960<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6961
6962<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6963<p>The first argument is a pointer to a value, the second is a pointer to a
6964 global string, the third is a pointer to a global string which is the source
6965 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6966
6967<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6968<p>This intrinsic allows annotation of local variables with arbitrary strings.
6969 This can be useful for special purpose optimizations that want to look for
6970 these annotations. These have no other defined use, they are ignored by code
6971 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6973</div>
6974
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6975<!-- _______________________________________________________________________ -->
6976<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6977 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6978</div>
6979
6980<div class="doc_text">
6981
6982<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6983<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6984 any integer bit width.</p>
6985
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6986<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6987 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6988 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6989 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6990 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6991 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]6992</pre>
6993
6994<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6995<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6996
6997<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6998<p>The first argument is an integer value (result of some expression), the
6999 second is a pointer to a global string, the third is a pointer to a global
7000 string which is the source file name, and the last argument is the line
7001 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7002
7003<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7004<p>This intrinsic allows annotations to be put on arbitrary expressions with
7005 arbitrary strings. This can be useful for special purpose optimizations that
7006 want to look for these annotations. These have no other defined use, they
7007 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7008
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7009</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7010
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7011<!-- _______________________________________________________________________ -->
7012<div class="doc_subsubsection">
7013 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7014</div>
7015
7016<div class="doc_text">
7017
7018<h5>Syntax:</h5>
7019<pre>
7020 declare void @llvm.trap()
7021</pre>
7022
7023<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7024<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7025
7026<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7027<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7028
7029<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7030<p>This intrinsics is lowered to the target dependent trap instruction. If the
7031 target does not have a trap instruction, this intrinsic will be lowered to
7032 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7033
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7034</div>
7035
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7036<!-- _______________________________________________________________________ -->
7037<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7038 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7039</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7040
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7041<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7042
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7043<h5>Syntax:</h5>
7044<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7045 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7046</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7047
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7048<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7049<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7050 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7051 ensure that it is placed on the stack before local variables.</p>
7052
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7053<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7054<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7055 arguments. The first argument is the value loaded from the stack
7056 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7057 that has enough space to hold the value of the guard.</p>
7058
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7059<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7060<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7061 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7062 stack. This is to ensure that if a local variable on the stack is
7063 overwritten, it will destroy the value of the guard. When the function exits,
7064 the guard on the stack is checked against the original guard. If they're
7065 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7066 function.</p>
7067
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7068</div>
7069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7070<!-- *********************************************************************** -->
7071<hr>
7072<address>
7073 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7074 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7075 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7076 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]7077
7078 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7079 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7080 Last modified: $Date$
7081</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7083</body>
7084</html>