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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 0762051d1dcf3bc5da0a5485942a5342b7c3eea8 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
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>
51 </ol>
52 </li>
53 <li><a href="#typesystem">Type System</a>
54 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]55 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]56 <li><a href="#t_primitive">Primitive Types</a>
57 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]58 <li><a href="#t_floating">Floating Point Types</a></li>
59 <li><a href="#t_void">Void Type</a></li>
60 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]61 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]62 </ol>
63 </li>
64 <li><a href="#t_derived">Derived Types</a>
65 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]66 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]67 <li><a href="#t_array">Array Type</a></li>
68 <li><a href="#t_function">Function Type</a></li>
69 <li><a href="#t_pointer">Pointer Type</a></li>
70 <li><a href="#t_struct">Structure Type</a></li>
71 <li><a href="#t_pstruct">Packed Structure Type</a></li>
72 <li><a href="#t_vector">Vector Type</a></li>
73 <li><a href="#t_opaque">Opaque Type</a></li>
74 </ol>
75 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]76 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]77 </ol>
78 </li>
79 <li><a href="#constants">Constants</a>
80 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]81 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]82 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]83 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
84 <li><a href="#undefvalues">Undefined Values</a></li>
85 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]86 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]87 </ol>
88 </li>
89 <li><a href="#othervalues">Other Values</a>
90 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]92 </ol>
93 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]94 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
95 <ol>
96 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]97 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
98 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]99 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
100 Global Variable</a></li>
101 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
102 Global Variable</a></li>
103 </ol>
104 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]105 <li><a href="#instref">Instruction Reference</a>
106 <ol>
107 <li><a href="#terminators">Terminator Instructions</a>
108 <ol>
109 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
110 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
111 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
112 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
113 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
114 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
115 </ol>
116 </li>
117 <li><a href="#binaryops">Binary Operations</a>
118 <ol>
119 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]120 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]122 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]124 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]125 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
126 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
127 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
128 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
129 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
130 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
131 </ol>
132 </li>
133 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
134 <ol>
135 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
136 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
137 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
138 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
139 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
140 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
141 </ol>
142 </li>
143 <li><a href="#vectorops">Vector Operations</a>
144 <ol>
145 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
146 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
147 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
148 </ol>
149 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]150 <li><a href="#aggregateops">Aggregate Operations</a>
151 <ol>
152 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
153 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
154 </ol>
155 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]156 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
157 <ol>
158 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
159 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
160 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
161 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
162 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
163 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
164 </ol>
165 </li>
166 <li><a href="#convertops">Conversion Operations</a>
167 <ol>
168 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
169 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
170 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
175 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
176 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
178 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
179 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
180 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]181 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]182 <li><a href="#otherops">Other Operations</a>
183 <ol>
184 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
185 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
186 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
187 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
188 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
189 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
190 </ol>
191 </li>
192 </ol>
193 </li>
194 <li><a href="#intrinsics">Intrinsic Functions</a>
195 <ol>
196 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
197 <ol>
198 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
199 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
201 </ol>
202 </li>
203 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
204 <ol>
205 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
206 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
208 </ol>
209 </li>
210 <li><a href="#int_codegen">Code Generator Intrinsics</a>
211 <ol>
212 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
213 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
215 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
216 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
217 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
218 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
219 </ol>
220 </li>
221 <li><a href="#int_libc">Standard C Library Intrinsics</a>
222 <ol>
223 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
224 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]228 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
229 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]231 </ol>
232 </li>
233 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
234 <ol>
235 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
236 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
237 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]239 </ol>
240 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]241 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
242 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]243 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
244 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
247 <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]248 <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]249 </ol>
250 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]251 <li><a href="#int_debugger">Debugger intrinsics</a></li>
252 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]253 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]254 <ol>
255 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]256 </ol>
257 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]258 <li><a href="#int_atomics">Atomic intrinsics</a>
259 <ol>
260 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
261 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
262 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
263 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
264 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
265 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
266 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
267 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
268 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
269 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
270 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
271 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
272 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
273 </ol>
274 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]275 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]276 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]277 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]278 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]279 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]280 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]281 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]282 '<tt>llvm.trap</tt>' Intrinsic</a></li>
283 <li><a href="#int_stackprotector">
284 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]285 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]286 </li>
287 </ol>
288 </li>
289</ol>
290
291<div class="doc_author">
292 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
293 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
294</div>
295
296<!-- *********************************************************************** -->
297<div class="doc_section"> <a name="abstract">Abstract </a></div>
298<!-- *********************************************************************** -->
299
300<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]301
302<p>This document is a reference manual for the LLVM assembly language. LLVM is
303 a Static Single Assignment (SSA) based representation that provides type
304 safety, low-level operations, flexibility, and the capability of representing
305 'all' high-level languages cleanly. It is the common code representation
306 used throughout all phases of the LLVM compilation strategy.</p>
307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]308</div>
309
310<!-- *********************************************************************** -->
311<div class="doc_section"> <a name="introduction">Introduction</a> </div>
312<!-- *********************************************************************** -->
313
314<div class="doc_text">
315
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]316<p>The LLVM code representation is designed to be used in three different forms:
317 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
318 for fast loading by a Just-In-Time compiler), and as a human readable
319 assembly language representation. This allows LLVM to provide a powerful
320 intermediate representation for efficient compiler transformations and
321 analysis, while providing a natural means to debug and visualize the
322 transformations. The three different forms of LLVM are all equivalent. This
323 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]324
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM representation aims to be light-weight and low-level while being
326 expressive, typed, and extensible at the same time. It aims to be a
327 "universal IR" of sorts, by being at a low enough level that high-level ideas
328 may be cleanly mapped to it (similar to how microprocessors are "universal
329 IR's", allowing many source languages to be mapped to them). By providing
330 type information, LLVM can be used as the target of optimizations: for
331 example, through pointer analysis, it can be proven that a C automatic
332 variable is never accessed outside of the current function... allowing it to
333 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334
335</div>
336
337<!-- _______________________________________________________________________ -->
338<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
339
340<div class="doc_text">
341
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342<p>It is important to note that this document describes 'well formed' LLVM
343 assembly language. There is a difference between what the parser accepts and
344 what is considered 'well formed'. For example, the following instruction is
345 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347<div class="doc_code">
348<pre>
349%x = <a href="#i_add">add</a> i32 1, %x
350</pre>
351</div>
352
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]353<p>...because the definition of <tt>%x</tt> does not dominate all of its
354 uses. The LLVM infrastructure provides a verification pass that may be used
355 to verify that an LLVM module is well formed. This pass is automatically run
356 by the parser after parsing input assembly and by the optimizer before it
357 outputs bitcode. The violations pointed out by the verifier pass indicate
358 bugs in transformation passes or input to the parser.</p>
359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]360</div>
361
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]362<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]363
364<!-- *********************************************************************** -->
365<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
366<!-- *********************************************************************** -->
367
368<div class="doc_text">
369
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]370<p>LLVM identifiers come in two basic types: global and local. Global
371 identifiers (functions, global variables) begin with the <tt>'@'</tt>
372 character. Local identifiers (register names, types) begin with
373 the <tt>'%'</tt> character. Additionally, there are three different formats
374 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]375
376<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]377 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]378 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
379 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
380 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
381 other characters in their names can be surrounded with quotes. Special
382 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
383 ASCII code for the character in hexadecimal. In this way, any character
384 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]385
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]386 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]387 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]388
389 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]390 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]391</ol>
392
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]393<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]394 don't need to worry about name clashes with reserved words, and the set of
395 reserved words may be expanded in the future without penalty. Additionally,
396 unnamed identifiers allow a compiler to quickly come up with a temporary
397 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]398
399<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]400 languages. There are keywords for different opcodes
401 ('<tt><a href="#i_add">add</a></tt>',
402 '<tt><a href="#i_bitcast">bitcast</a></tt>',
403 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
404 ('<tt><a href="#t_void">void</a></tt>',
405 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
406 reserved words cannot conflict with variable names, because none of them
407 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]408
409<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]410 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]411
412<p>The easy way:</p>
413
414<div class="doc_code">
415<pre>
416%result = <a href="#i_mul">mul</a> i32 %X, 8
417</pre>
418</div>
419
420<p>After strength reduction:</p>
421
422<div class="doc_code">
423<pre>
424%result = <a href="#i_shl">shl</a> i32 %X, i8 3
425</pre>
426</div>
427
428<p>And the hard way:</p>
429
430<div class="doc_code">
431<pre>
432<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
433<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
434%result = <a href="#i_add">add</a> i32 %1, %1
435</pre>
436</div>
437
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]438<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
439 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]440
441<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]442 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]443 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]444
445 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]446 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]447
448 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]449</ol>
450
451<p>...and it also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]452 demonstrating instructions, we will follow an instruction with a comment that
453 defines the type and name of value produced. Comments are shown in italic
454 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]455
456</div>
457
458<!-- *********************************************************************** -->
459<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
460<!-- *********************************************************************** -->
461
462<!-- ======================================================================= -->
463<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
464</div>
465
466<div class="doc_text">
467
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]468<p>LLVM programs are composed of "Module"s, each of which is a translation unit
469 of the input programs. Each module consists of functions, global variables,
470 and symbol table entries. Modules may be combined together with the LLVM
471 linker, which merges function (and global variable) definitions, resolves
472 forward declarations, and merges symbol table entries. Here is an example of
473 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]474
475<div class="doc_code">
476<pre><i>; Declare the string constant as a global constant...</i>
477<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
478 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
479
480<i>; External declaration of the puts function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]481<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]482
483<i>; Definition of main function</i>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]484define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]485 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]486 %cast210 = <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]487 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]488
489 <i>; Call puts function to write out the string to stdout...</i>
490 <a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]491 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]492 <a
493 href="#i_ret">ret</a> i32 0<br>}<br>
494</pre>
495</div>
496
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]497<p>This example is made up of a <a href="#globalvars">global variable</a> named
498 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
499 a <a href="#functionstructure">function definition</a> for
500 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]501
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]502<p>In general, a module is made up of a list of global values, where both
503 functions and global variables are global values. Global values are
504 represented by a pointer to a memory location (in this case, a pointer to an
505 array of char, and a pointer to a function), and have one of the
506 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507
508</div>
509
510<!-- ======================================================================= -->
511<div class="doc_subsection">
512 <a name="linkage">Linkage Types</a>
513</div>
514
515<div class="doc_text">
516
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]517<p>All Global Variables and Functions have one of the following types of
518 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]519
520<dl>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]521 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]522 <dd>Global values with private linkage are only directly accessible by objects
523 in the current module. In particular, linking code into a module with an
524 private global value may cause the private to be renamed as necessary to
525 avoid collisions. Because the symbol is private to the module, all
526 references can be updated. This doesn't show up in any symbol table in the
527 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]528
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]529 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]530 <dd>Similar to private, but the symbol is passed through the assembler and
531 removed by the linker after evaluation.</dd>
532
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]533 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]534 <dd>Similar to private, but the value shows as a local symbol
535 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
536 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]537
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]538 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]539 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]540 into the object file corresponding to the LLVM module. They exist to
541 allow inlining and other optimizations to take place given knowledge of
542 the definition of the global, which is known to be somewhere outside the
543 module. Globals with <tt>available_externally</tt> linkage are allowed to
544 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
545 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]547 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]548 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]549 the same name when linkage occurs. This is typically used to implement
550 inline functions, templates, or other code which must be generated in each
551 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
552 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]553
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]554 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]555 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
556 linkage, except that unreferenced <tt>common</tt> globals may not be
557 discarded. This is used for globals that may be emitted in multiple
558 translation units, but that are not guaranteed to be emitted into every
559 translation unit that uses them. One example of this is tentative
560 definitions in C, such as "<tt>int X;</tt>" at global scope.</dd>
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]562 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]563 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]564 that some targets may choose to emit different assembly sequences for them
565 for target-dependent reasons. This is used for globals that are declared
566 "weak" in C source code.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]567
568 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]569 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]570 pointer to array type. When two global variables with appending linkage
571 are linked together, the two global arrays are appended together. This is
572 the LLVM, typesafe, equivalent of having the system linker append together
573 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]574
575 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]576 <dd>The semantics of this linkage follow the ELF object file model: the symbol
577 is weak until linked, if not linked, the symbol becomes null instead of
578 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]579
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]580 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]581 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]582 <dd>Some languages allow differing globals to be merged, such as two functions
583 with different semantics. Other languages, such as <tt>C++</tt>, ensure
584 that only equivalent globals are ever merged (the "one definition rule" -
585 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
586 and <tt>weak_odr</tt> linkage types to indicate that the global will only
587 be merged with equivalent globals. These linkage types are otherwise the
588 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]590 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]591 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]592 visible, meaning that it participates in linkage and can be used to
593 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]594</dl>
595
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]596<p>The next two types of linkage are targeted for Microsoft Windows platform
597 only. They are designed to support importing (exporting) symbols from (to)
598 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]599
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]600<dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]601 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]602 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]603 or variable via a global pointer to a pointer that is set up by the DLL
604 exporting the symbol. On Microsoft Windows targets, the pointer name is
605 formed by combining <code>__imp_</code> and the function or variable
606 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]607
608 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]609 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]610 pointer to a pointer in a DLL, so that it can be referenced with the
611 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
612 name is formed by combining <code>__imp_</code> and the function or
613 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]614</dl>
615
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]616<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
617 another module defined a "<tt>.LC0</tt>" variable and was linked with this
618 one, one of the two would be renamed, preventing a collision. Since
619 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
620 declarations), they are accessible outside of the current module.</p>
621
622<p>It is illegal for a function <i>declaration</i> to have any linkage type
623 other than "externally visible", <tt>dllimport</tt>
624 or <tt>extern_weak</tt>.</p>
625
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]626<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]627 or <tt>weak_odr</tt> linkages.</p>
628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]629</div>
630
631<!-- ======================================================================= -->
632<div class="doc_subsection">
633 <a name="callingconv">Calling Conventions</a>
634</div>
635
636<div class="doc_text">
637
638<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]639 and <a href="#i_invoke">invokes</a> can all have an optional calling
640 convention specified for the call. The calling convention of any pair of
641 dynamic caller/callee must match, or the behavior of the program is
642 undefined. The following calling conventions are supported by LLVM, and more
643 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]644
645<dl>
646 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]647 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]648 specified) matches the target C calling conventions. This calling
649 convention supports varargs function calls and tolerates some mismatch in
650 the declared prototype and implemented declaration of the function (as
651 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]652
653 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]654 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]655 (e.g. by passing things in registers). This calling convention allows the
656 target to use whatever tricks it wants to produce fast code for the
657 target, without having to conform to an externally specified ABI
658 (Application Binary Interface). Implementations of this convention should
659 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
660 optimization</a> to be supported. This calling convention does not
661 support varargs and requires the prototype of all callees to exactly match
662 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663
664 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]665 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]666 as possible under the assumption that the call is not commonly executed.
667 As such, these calls often preserve all registers so that the call does
668 not break any live ranges in the caller side. This calling convention
669 does not support varargs and requires the prototype of all callees to
670 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]671
672 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]673 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]674 target-specific calling conventions to be used. Target specific calling
675 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]676</dl>
677
678<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]679 support Pascal conventions or any other well-known target-independent
680 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681
682</div>
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
686 <a name="visibility">Visibility Styles</a>
687</div>
688
689<div class="doc_text">
690
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]691<p>All Global Variables and Functions have one of the following visibility
692 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]693
694<dl>
695 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]696 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]697 that the declaration is visible to other modules and, in shared libraries,
698 means that the declared entity may be overridden. On Darwin, default
699 visibility means that the declaration is visible to other modules. Default
700 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]701
702 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]703 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]704 object if they are in the same shared object. Usually, hidden visibility
705 indicates that the symbol will not be placed into the dynamic symbol
706 table, so no other module (executable or shared library) can reference it
707 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]708
709 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]711 the dynamic symbol table, but that references within the defining module
712 will bind to the local symbol. That is, the symbol cannot be overridden by
713 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]714</dl>
715
716</div>
717
718<!-- ======================================================================= -->
719<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]720 <a name="namedtypes">Named Types</a>
721</div>
722
723<div class="doc_text">
724
725<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]726 it easier to read the IR and make the IR more condensed (particularly when
727 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]728
729<div class="doc_code">
730<pre>
731%mytype = type { %mytype*, i32 }
732</pre>
733</div>
734
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]735<p>You may give a name to any <a href="#typesystem">type</a> except
736 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
737 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]738
739<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]740 and that you can therefore specify multiple names for the same type. This
741 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
742 uses structural typing, the name is not part of the type. When printing out
743 LLVM IR, the printer will pick <em>one name</em> to render all types of a
744 particular shape. This means that if you have code where two different
745 source types end up having the same LLVM type, that the dumper will sometimes
746 print the "wrong" or unexpected type. This is an important design point and
747 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]748
749</div>
750
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]751<!-- ======================================================================= -->
752<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]753 <a name="globalvars">Global Variables</a>
754</div>
755
756<div class="doc_text">
757
758<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]759 instead of run-time. Global variables may optionally be initialized, may
760 have an explicit section to be placed in, and may have an optional explicit
761 alignment specified. A variable may be defined as "thread_local", which
762 means that it will not be shared by threads (each thread will have a
763 separated copy of the variable). A variable may be defined as a global
764 "constant," which indicates that the contents of the variable
765 will <b>never</b> be modified (enabling better optimization, allowing the
766 global data to be placed in the read-only section of an executable, etc).
767 Note that variables that need runtime initialization cannot be marked
768 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]769
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]770<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
771 constant, even if the final definition of the global is not. This capability
772 can be used to enable slightly better optimization of the program, but
773 requires the language definition to guarantee that optimizations based on the
774 'constantness' are valid for the translation units that do not include the
775 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]776
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]777<p>As SSA values, global variables define pointer values that are in scope
778 (i.e. they dominate) all basic blocks in the program. Global variables
779 always define a pointer to their "content" type because they describe a
780 region of memory, and all memory objects in LLVM are accessed through
781 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]782
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]783<p>A global variable may be declared to reside in a target-specific numbered
784 address space. For targets that support them, address spaces may affect how
785 optimizations are performed and/or what target instructions are used to
786 access the variable. The default address space is zero. The address space
787 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]789<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]790 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]791
792<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]793 the alignment is set to zero, the alignment of the global is set by the
794 target to whatever it feels convenient. If an explicit alignment is
795 specified, the global is forced to have at least that much alignment. All
796 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]797
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]798<p>For example, the following defines a global in a numbered address space with
799 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800
801<div class="doc_code">
802<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]803@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]804</pre>
805</div>
806
807</div>
808
809
810<!-- ======================================================================= -->
811<div class="doc_subsection">
812 <a name="functionstructure">Functions</a>
813</div>
814
815<div class="doc_text">
816
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]817<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
818 optional <a href="#linkage">linkage type</a>, an optional
819 <a href="#visibility">visibility style</a>, an optional
820 <a href="#callingconv">calling convention</a>, a return type, an optional
821 <a href="#paramattrs">parameter attribute</a> for the return type, a function
822 name, a (possibly empty) argument list (each with optional
823 <a href="#paramattrs">parameter attributes</a>), optional
824 <a href="#fnattrs">function attributes</a>, an optional section, an optional
825 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
826 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]827
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]828<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
829 optional <a href="#linkage">linkage type</a>, an optional
830 <a href="#visibility">visibility style</a>, an optional
831 <a href="#callingconv">calling convention</a>, a return type, an optional
832 <a href="#paramattrs">parameter attribute</a> for the return type, a function
833 name, a possibly empty list of arguments, an optional alignment, and an
834 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]835
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]836<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]837 (Control Flow Graph) for the function. Each basic block may optionally start
838 with a label (giving the basic block a symbol table entry), contains a list
839 of instructions, and ends with a <a href="#terminators">terminator</a>
840 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]841
842<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]843 executed on entrance to the function, and it is not allowed to have
844 predecessor basic blocks (i.e. there can not be any branches to the entry
845 block of a function). Because the block can have no predecessors, it also
846 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]847
848<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]849 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]850
851<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]852 the alignment is set to zero, the alignment of the function is set by the
853 target to whatever it feels convenient. If an explicit alignment is
854 specified, the function is forced to have at least that much alignment. All
855 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]857<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]858<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]859<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]860define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]861 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
862 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
863 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
864 [<a href="#gc">gc</a>] { ... }
865</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]866</div>
867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]868</div>
869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]870<!-- ======================================================================= -->
871<div class="doc_subsection">
872 <a name="aliasstructure">Aliases</a>
873</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]874
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]875<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]876
877<p>Aliases act as "second name" for the aliasee value (which can be either
878 function, global variable, another alias or bitcast of global value). Aliases
879 may have an optional <a href="#linkage">linkage type</a>, and an
880 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]881
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]882<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]883<div class="doc_code">
884<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]885@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]886</pre>
887</div>
888
889</div>
890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891<!-- ======================================================================= -->
892<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]893
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]894<div class="doc_text">
895
896<p>The return type and each parameter of a function type may have a set of
897 <i>parameter attributes</i> associated with them. Parameter attributes are
898 used to communicate additional information about the result or parameters of
899 a function. Parameter attributes are considered to be part of the function,
900 not of the function type, so functions with different parameter attributes
901 can have the same function type.</p>
902
903<p>Parameter attributes are simple keywords that follow the type specified. If
904 multiple parameter attributes are needed, they are space separated. For
905 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]906
907<div class="doc_code">
908<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]909declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]910declare i32 @atoi(i8 zeroext)
911declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]912</pre>
913</div>
914
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]915<p>Note that any attributes for the function result (<tt>nounwind</tt>,
916 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]917
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]918<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]919
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]920<dl>
921 <dt><tt>zeroext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]922 <dd>This indicates to the code generator that the parameter or return value
923 should be zero-extended to a 32-bit value by the caller (for a parameter)
924 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]925
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]926 <dt><tt>signext</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]927 <dd>This indicates to the code generator that the parameter or return value
928 should be sign-extended to a 32-bit value by the caller (for a parameter)
929 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]930
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931 <dt><tt>inreg</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]932 <dd>This indicates that this parameter or return value should be treated in a
933 special target-dependent fashion during while emitting code for a function
934 call or return (usually, by putting it in a register as opposed to memory,
935 though some targets use it to distinguish between two different kinds of
936 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]937
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]938 <dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]939 <dd>This indicates that the pointer parameter should really be passed by value
940 to the function. The attribute implies that a hidden copy of the pointee
941 is made between the caller and the callee, so the callee is unable to
942 modify the value in the callee. This attribute is only valid on LLVM
943 pointer arguments. It is generally used to pass structs and arrays by
944 value, but is also valid on pointers to scalars. The copy is considered
945 to belong to the caller not the callee (for example,
946 <tt><a href="#readonly">readonly</a></tt> functions should not write to
947 <tt>byval</tt> parameters). This is not a valid attribute for return
948 values. The byval attribute also supports specifying an alignment with
949 the align attribute. This has a target-specific effect on the code
950 generator that usually indicates a desired alignment for the synthesized
951 stack slot.</dd>
952
953 <dt><tt>sret</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]954 <dd>This indicates that the pointer parameter specifies the address of a
955 structure that is the return value of the function in the source program.
956 This pointer must be guaranteed by the caller to be valid: loads and
957 stores to the structure may be assumed by the callee to not to trap. This
958 may only be applied to the first parameter. This is not a valid attribute
959 for return values. </dd>
960
961 <dt><tt>noalias</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]962 <dd>This indicates that the pointer does not alias any global or any other
963 parameter. The caller is responsible for ensuring that this is the
964 case. On a function return value, <tt>noalias</tt> additionally indicates
965 that the pointer does not alias any other pointers visible to the
966 caller. For further details, please see the discussion of the NoAlias
967 response in
968 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
969 analysis</a>.</dd>
970
971 <dt><tt>nocapture</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]972 <dd>This indicates that the callee does not make any copies of the pointer
973 that outlive the callee itself. This is not a valid attribute for return
974 values.</dd>
975
976 <dt><tt>nest</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates that the pointer parameter can be excised using the
978 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
979 attribute for return values.</dd>
980</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]981
982</div>
983
984<!-- ======================================================================= -->
985<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]986 <a name="gc">Garbage Collector Names</a>
987</div>
988
989<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]990
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]991<p>Each function may specify a garbage collector name, which is simply a
992 string:</p>
993
994<div class="doc_code">
995<pre>
996define void @f() gc "name" { ...
997</pre>
998</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]999
1000<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1001 collector which will cause the compiler to alter its output in order to
1002 support the named garbage collection algorithm.</p>
1003
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1004</div>
1005
1006<!-- ======================================================================= -->
1007<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1008 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1009</div>
1010
1011<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1012
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1013<p>Function attributes are set to communicate additional information about a
1014 function. Function attributes are considered to be part of the function, not
1015 of the function type, so functions with different parameter attributes can
1016 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1017
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1018<p>Function attributes are simple keywords that follow the type specified. If
1019 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1020
1021<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1022<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1023define void @f() noinline { ... }
1024define void @f() alwaysinline { ... }
1025define void @f() alwaysinline optsize { ... }
1026define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1027</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1028</div>
1029
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1030<dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1031 <dt><tt>alwaysinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This attribute indicates that the inliner should attempt to inline this
1033 function into callers whenever possible, ignoring any active inlining size
1034 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1035
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1036 <dt><tt>noinline</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1037 <dd>This attribute indicates that the inliner should never inline this
1038 function in any situation. This attribute may not be used together with
1039 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1040
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1041 <dt><tt>optsize</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1042 <dd>This attribute suggests that optimization passes and code generator passes
1043 make choices that keep the code size of this function low, and otherwise
1044 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1045
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046 <dt><tt>noreturn</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1047 <dd>This function attribute indicates that the function never returns
1048 normally. This produces undefined behavior at runtime if the function
1049 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1050
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1051 <dt><tt>nounwind</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1052 <dd>This function attribute indicates that the function never returns with an
1053 unwind or exceptional control flow. If the function does unwind, its
1054 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1055
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dt><tt>readnone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1057 <dd>This attribute indicates that the function computes its result (or decides
1058 to unwind an exception) based strictly on its arguments, without
1059 dereferencing any pointer arguments or otherwise accessing any mutable
1060 state (e.g. memory, control registers, etc) visible to caller functions.
1061 It does not write through any pointer arguments
1062 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1063 changes any state visible to callers. This means that it cannot unwind
1064 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1065 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1066
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1067 <dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068 <dd>This attribute indicates that the function does not write through any
1069 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1070 arguments) or otherwise modify any state (e.g. memory, control registers,
1071 etc) visible to caller functions. It may dereference pointer arguments
1072 and read state that may be set in the caller. A readonly function always
1073 returns the same value (or unwinds an exception identically) when called
1074 with the same set of arguments and global state. It cannot unwind an
1075 exception by calling the <tt>C++</tt> exception throwing methods, but may
1076 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1077
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1078 <dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1079 <dd>This attribute indicates that the function should emit a stack smashing
1080 protector. It is in the form of a "canary"&mdash;a random value placed on
1081 the stack before the local variables that's checked upon return from the
1082 function to see if it has been overwritten. A heuristic is used to
1083 determine if a function needs stack protectors or not.<br>
1084<br>
1085 If a function that has an <tt>ssp</tt> attribute is inlined into a
1086 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1087 function will have an <tt>ssp</tt> attribute.</dd>
1088
1089 <dt><tt>sspreq</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1090 <dd>This attribute indicates that the function should <em>always</em> emit a
1091 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1092 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1093<br>
1094 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1095 function that doesn't have an <tt>sspreq</tt> attribute or which has
1096 an <tt>ssp</tt> attribute, then the resulting function will have
1097 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1098
1099 <dt><tt>noredzone</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1100 <dd>This attribute indicates that the code generator should not use a red
1101 zone, even if the target-specific ABI normally permits it.</dd>
1102
1103 <dt><tt>noimplicitfloat</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1104 <dd>This attributes disables implicit floating point instructions.</dd>
1105
1106 <dt><tt>naked</tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This attribute disables prologue / epilogue emission for the function.
1108 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1109</dl>
1110
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1111</div>
1112
1113<!-- ======================================================================= -->
1114<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1115 <a name="moduleasm">Module-Level Inline Assembly</a>
1116</div>
1117
1118<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119
1120<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1121 the GCC "file scope inline asm" blocks. These blocks are internally
1122 concatenated by LLVM and treated as a single unit, but may be separated in
1123 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1124
1125<div class="doc_code">
1126<pre>
1127module asm "inline asm code goes here"
1128module asm "more can go here"
1129</pre>
1130</div>
1131
1132<p>The strings can contain any character by escaping non-printable characters.
1133 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]1134 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1135
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1136<p>The inline asm code is simply printed to the machine code .s file when
1137 assembly code is generated.</p>
1138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1139</div>
1140
1141<!-- ======================================================================= -->
1142<div class="doc_subsection">
1143 <a name="datalayout">Data Layout</a>
1144</div>
1145
1146<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1147
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1148<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1149 data is to be laid out in memory. The syntax for the data layout is
1150 simply:</p>
1151
1152<div class="doc_code">
1153<pre>
1154target datalayout = "<i>layout specification</i>"
1155</pre>
1156</div>
1157
1158<p>The <i>layout specification</i> consists of a list of specifications
1159 separated by the minus sign character ('-'). Each specification starts with
1160 a letter and may include other information after the letter to define some
1161 aspect of the data layout. The specifications accepted are as follows:</p>
1162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1163<dl>
1164 <dt><tt>E</tt></dt>
1165 <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]1166 bits with the most significance have the lowest address location.</dd>
1167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1168 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1169 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1170 the bits with the least significance have the lowest address
1171 location.</dd>
1172
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1173 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1174 <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]1175 <i>preferred</i> alignments. All sizes are in bits. Specifying
1176 the <i>pref</i> alignment is optional. If omitted, the
1177 preceding <tt>:</tt> should be omitted too.</dd>
1178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1179 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1180 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1181 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1182
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1183 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1184 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1185 <i>size</i>.</dd>
1186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1187 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1188 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1189 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1190 (double).</dd>
1191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1192 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1193 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1194 <i>size</i>.</dd>
1195
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1196 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1197 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1198 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1199</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1201<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1202 default set of specifications which are then (possibly) overriden by the
1203 specifications in the <tt>datalayout</tt> keyword. The default specifications
1204 are given in this list:</p>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206<ul>
1207 <li><tt>E</tt> - big endian</li>
1208 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1209 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1210 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1211 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1212 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1213 <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]1214 alignment of 64-bits</li>
1215 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1216 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1217 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1218 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1219 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1220 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1221</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1222
1223<p>When LLVM is determining the alignment for a given type, it uses the
1224 following rules:</p>
1225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1226<ol>
1227 <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]1228 specification is used.</li>
1229
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1230 <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]1231 smallest integer type that is larger than the bitwidth of the sought type
1232 is used. If none of the specifications are larger than the bitwidth then
1233 the the largest integer type is used. For example, given the default
1234 specifications above, the i7 type will use the alignment of i8 (next
1235 largest) while both i65 and i256 will use the alignment of i64 (largest
1236 specified).</li>
1237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238 <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]1239 largest vector type that is smaller than the sought vector type will be
1240 used as a fall back. This happens because &lt;128 x double&gt; can be
1241 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1242</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1244</div>
1245
1246<!-- *********************************************************************** -->
1247<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1248<!-- *********************************************************************** -->
1249
1250<div class="doc_text">
1251
1252<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1253 intermediate representation. Being typed enables a number of optimizations
1254 to be performed on the intermediate representation directly, without having
1255 to do extra analyses on the side before the transformation. A strong type
1256 system makes it easier to read the generated code and enables novel analyses
1257 and transformations that are not feasible to perform on normal three address
1258 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259
1260</div>
1261
1262<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1263<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1266<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1267
1268<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1269
1270<table border="1" cellspacing="0" cellpadding="4">
1271 <tbody>
1272 <tr><th>Classification</th><th>Types</th></tr>
1273 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1274 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1275 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1276 </tr>
1277 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1278 <td><a href="#t_floating">floating point</a></td>
1279 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1280 </tr>
1281 <tr>
1282 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1283 <td><a href="#t_integer">integer</a>,
1284 <a href="#t_floating">floating point</a>,
1285 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1286 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1287 <a href="#t_struct">structure</a>,
1288 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1289 <a href="#t_label">label</a>,
1290 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1291 </td>
1292 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1293 <tr>
1294 <td><a href="#t_primitive">primitive</a></td>
1295 <td><a href="#t_label">label</a>,
1296 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1297 <a href="#t_floating">floating point</a>,
1298 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1299 </tr>
1300 <tr>
1301 <td><a href="#t_derived">derived</a></td>
1302 <td><a href="#t_integer">integer</a>,
1303 <a href="#t_array">array</a>,
1304 <a href="#t_function">function</a>,
1305 <a href="#t_pointer">pointer</a>,
1306 <a href="#t_struct">structure</a>,
1307 <a href="#t_pstruct">packed structure</a>,
1308 <a href="#t_vector">vector</a>,
1309 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1310 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1311 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1312 </tbody>
1313</table>
1314
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1315<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1316 important. Values of these types are the only ones which can be produced by
1317 instructions, passed as arguments, or used as operands to instructions.</p>
1318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1319</div>
1320
1321<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1322<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1323
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1324<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1325
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1326<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1327 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1328
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1329</div>
1330
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1331<!-- _______________________________________________________________________ -->
1332<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1333
1334<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1335
1336<table>
1337 <tbody>
1338 <tr><th>Type</th><th>Description</th></tr>
1339 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1340 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1341 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1342 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1343 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1344 </tbody>
1345</table>
1346
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1347</div>
1348
1349<!-- _______________________________________________________________________ -->
1350<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1351
1352<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1353
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1354<h5>Overview:</h5>
1355<p>The void type does not represent any value and has no size.</p>
1356
1357<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1358<pre>
1359 void
1360</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1361
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1362</div>
1363
1364<!-- _______________________________________________________________________ -->
1365<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1366
1367<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1368
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1369<h5>Overview:</h5>
1370<p>The label type represents code labels.</p>
1371
1372<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1373<pre>
1374 label
1375</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1376
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1377</div>
1378
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1379<!-- _______________________________________________________________________ -->
1380<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1381
1382<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1383
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1384<h5>Overview:</h5>
1385<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1386 may contain metadata is <tt>metadata*</tt> or a function type that returns or
1387 takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1388
1389<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1390<pre>
1391 metadata
1392</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1393
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1394</div>
1395
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1396
1397<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1398<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1399
1400<div class="doc_text">
1401
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1402<p>The real power in LLVM comes from the derived types in the system. This is
1403 what allows a programmer to represent arrays, functions, pointers, and other
1404 useful types. Note that these derived types may be recursive: For example,
1405 it is possible to have a two dimensional array.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1406
1407</div>
1408
1409<!-- _______________________________________________________________________ -->
1410<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1411
1412<div class="doc_text">
1413
1414<h5>Overview:</h5>
1415<p>The integer type is a very simple derived type that simply specifies an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1416 arbitrary bit width for the integer type desired. Any bit width from 1 bit to
1417 2^23-1 (about 8 million) can be specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1418
1419<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1420<pre>
1421 iN
1422</pre>
1423
1424<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]1425 value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1426
1427<h5>Examples:</h5>
1428<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1429 <tr class="layout">
1430 <td class="left"><tt>i1</tt></td>
1431 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1432 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1433 <tr class="layout">
1434 <td class="left"><tt>i32</tt></td>
1435 <td class="left">a 32-bit integer.</td>
1436 </tr>
1437 <tr class="layout">
1438 <td class="left"><tt>i1942652</tt></td>
1439 <td class="left">a really big integer of over 1 million bits.</td>
1440 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1441</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1442
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1443<p>Note that the code generator does not yet support large integer types to be
1444 used as function return types. The specific limit on how large a return type
1445 the code generator can currently handle is target-dependent; currently it's
1446 often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1447
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1448</div>
1449
1450<!-- _______________________________________________________________________ -->
1451<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1452
1453<div class="doc_text">
1454
1455<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1456<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1457 sequentially in memory. The array type requires a size (number of elements)
1458 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1459
1460<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1461<pre>
1462 [&lt;# elements&gt; x &lt;elementtype&gt;]
1463</pre>
1464
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1465<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1466 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1467
1468<h5>Examples:</h5>
1469<table class="layout">
1470 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1471 <td class="left"><tt>[40 x i32]</tt></td>
1472 <td class="left">Array of 40 32-bit integer values.</td>
1473 </tr>
1474 <tr class="layout">
1475 <td class="left"><tt>[41 x i32]</tt></td>
1476 <td class="left">Array of 41 32-bit integer values.</td>
1477 </tr>
1478 <tr class="layout">
1479 <td class="left"><tt>[4 x i8]</tt></td>
1480 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1481 </tr>
1482</table>
1483<p>Here are some examples of multidimensional arrays:</p>
1484<table class="layout">
1485 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1486 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1487 <td class="left">3x4 array of 32-bit integer values.</td>
1488 </tr>
1489 <tr class="layout">
1490 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1491 <td class="left">12x10 array of single precision floating point values.</td>
1492 </tr>
1493 <tr class="layout">
1494 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1495 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1496 </tr>
1497</table>
1498
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1499<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1500 length array. Normally, accesses past the end of an array are undefined in
1501 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1502 a special case, however, zero length arrays are recognized to be variable
1503 length. This allows implementation of 'pascal style arrays' with the LLVM
1504 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1505
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1506<p>Note that the code generator does not yet support large aggregate types to be
1507 used as function return types. The specific limit on how large an aggregate
1508 return type the code generator can currently handle is target-dependent, and
1509 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1511</div>
1512
1513<!-- _______________________________________________________________________ -->
1514<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1516<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1518<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1519<p>The function type can be thought of as a function signature. It consists of
1520 a return type and a list of formal parameter types. The return type of a
1521 function type is a scalar type, a void type, or a struct type. If the return
1522 type is a struct type then all struct elements must be of first class types,
1523 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1525<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1526<pre>
1527 &lt;returntype list&gt; (&lt;parameter list&gt;)
1528</pre>
1529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1530<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]1531 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1532 which indicates that the function takes a variable number of arguments.
1533 Variable argument functions can access their arguments with
1534 the <a href="#int_varargs">variable argument handling intrinsic</a>
1535 functions. '<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1536 <a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1538<h5>Examples:</h5>
1539<table class="layout">
1540 <tr class="layout">
1541 <td class="left"><tt>i32 (i32)</tt></td>
1542 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1543 </td>
1544 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1545 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1546 </tt></td>
1547 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1548 an <tt>i16</tt> that should be sign extended and a
1549 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1550 <tt>float</tt>.
1551 </td>
1552 </tr><tr class="layout">
1553 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1554 <td class="left">A vararg function that takes at least one
1555 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1556 which returns an integer. This is the signature for <tt>printf</tt> in
1557 LLVM.
1558 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1559 </tr><tr class="layout">
1560 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1561 <td class="left">A function taking an <tt>i32</tt>, returning two
1562 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1563 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1564 </tr>
1565</table>
1566
1567</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1569<!-- _______________________________________________________________________ -->
1570<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1572<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1574<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1575<p>The structure type is used to represent a collection of data members together
1576 in memory. The packing of the field types is defined to match the ABI of the
1577 underlying processor. The elements of a structure may be any type that has a
1578 size.</p>
1579
1580<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1581 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1582 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1584<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1585<pre>
1586 { &lt;type list&gt; }
1587</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1589<h5>Examples:</h5>
1590<table class="layout">
1591 <tr class="layout">
1592 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1593 <td class="left">A triple of three <tt>i32</tt> values</td>
1594 </tr><tr class="layout">
1595 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1596 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1597 second element is a <a href="#t_pointer">pointer</a> to a
1598 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1599 an <tt>i32</tt>.</td>
1600 </tr>
1601</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1602
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1603<p>Note that the code generator does not yet support large aggregate types to be
1604 used as function return types. The specific limit on how large an aggregate
1605 return type the code generator can currently handle is target-dependent, and
1606 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1608</div>
1609
1610<!-- _______________________________________________________________________ -->
1611<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1612</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1614<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1616<h5>Overview:</h5>
1617<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1618 together in memory. There is no padding between fields. Further, the
1619 alignment of a packed structure is 1 byte. The elements of a packed
1620 structure may be any type that has a size.</p>
1621
1622<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1623 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1624 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1626<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1627<pre>
1628 &lt; { &lt;type list&gt; } &gt;
1629</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1631<h5>Examples:</h5>
1632<table class="layout">
1633 <tr class="layout">
1634 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1635 <td class="left">A triple of three <tt>i32</tt> values</td>
1636 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1637 <td class="left">
1638<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1639 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1640 second element is a <a href="#t_pointer">pointer</a> to a
1641 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1642 an <tt>i32</tt>.</td>
1643 </tr>
1644</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1646</div>
1647
1648<!-- _______________________________________________________________________ -->
1649<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1650
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1651<div class="doc_text">
1652
1653<h5>Overview:</h5>
1654<p>As in many languages, the pointer type represents a pointer or reference to
1655 another object, which must live in memory. Pointer types may have an optional
1656 address space attribute defining the target-specific numbered address space
1657 where the pointed-to object resides. The default address space is zero.</p>
1658
1659<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1660 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1662<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1663<pre>
1664 &lt;type&gt; *
1665</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1666
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1667<h5>Examples:</h5>
1668<table class="layout">
1669 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1670 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1671 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1672 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1673 </tr>
1674 <tr class="layout">
1675 <td class="left"><tt>i32 (i32 *) *</tt></td>
1676 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1677 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1678 <tt>i32</tt>.</td>
1679 </tr>
1680 <tr class="layout">
1681 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1682 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1683 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1684 </tr>
1685</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1687</div>
1688
1689<!-- _______________________________________________________________________ -->
1690<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1692<div class="doc_text">
1693
1694<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1695<p>A vector type is a simple derived type that represents a vector of elements.
1696 Vector types are used when multiple primitive data are operated in parallel
1697 using a single instruction (SIMD). A vector type requires a size (number of
1698 elements) and an underlying primitive data type. Vectors must have a power
1699 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1700 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1701
1702<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1703<pre>
1704 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1705</pre>
1706
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1707<p>The number of elements is a constant integer value; elementtype may be any
1708 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1709
1710<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1711<table class="layout">
1712 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1713 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1714 <td class="left">Vector of 4 32-bit integer values.</td>
1715 </tr>
1716 <tr class="layout">
1717 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1718 <td class="left">Vector of 8 32-bit floating-point values.</td>
1719 </tr>
1720 <tr class="layout">
1721 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1722 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1723 </tr>
1724</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1725
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1726<p>Note that the code generator does not yet support large vector types to be
1727 used as function return types. The specific limit on how large a vector
1728 return type codegen can currently handle is target-dependent; currently it's
1729 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1731</div>
1732
1733<!-- _______________________________________________________________________ -->
1734<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1735<div class="doc_text">
1736
1737<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1738<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1739 corresponds (for example) to the C notion of a forward declared structure
1740 type. In LLVM, opaque types can eventually be resolved to any type (not just
1741 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1742
1743<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1744<pre>
1745 opaque
1746</pre>
1747
1748<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1749<table class="layout">
1750 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1751 <td class="left"><tt>opaque</tt></td>
1752 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1753 </tr>
1754</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1756</div>
1757
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1758<!-- ======================================================================= -->
1759<div class="doc_subsection">
1760 <a name="t_uprefs">Type Up-references</a>
1761</div>
1762
1763<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1764
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1765<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1766<p>An "up reference" allows you to refer to a lexically enclosing type without
1767 requiring it to have a name. For instance, a structure declaration may
1768 contain a pointer to any of the types it is lexically a member of. Example
1769 of up references (with their equivalent as named type declarations)
1770 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1771
1772<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1773 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1774 { \2 }* %y = type { %y }*
1775 \1* %z = type %z*
1776</pre>
1777
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1778<p>An up reference is needed by the asmprinter for printing out cyclic types
1779 when there is no declared name for a type in the cycle. Because the
1780 asmprinter does not want to print out an infinite type string, it needs a
1781 syntax to handle recursive types that have no names (all names are optional
1782 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1783
1784<h5>Syntax:</h5>
1785<pre>
1786 \&lt;level&gt;
1787</pre>
1788
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1789<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]1790
1791<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1792<table class="layout">
1793 <tr class="layout">
1794 <td class="left"><tt>\1*</tt></td>
1795 <td class="left">Self-referential pointer.</td>
1796 </tr>
1797 <tr class="layout">
1798 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1799 <td class="left">Recursive structure where the upref refers to the out-most
1800 structure.</td>
1801 </tr>
1802</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1803
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1804</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1805
1806<!-- *********************************************************************** -->
1807<div class="doc_section"> <a name="constants">Constants</a> </div>
1808<!-- *********************************************************************** -->
1809
1810<div class="doc_text">
1811
1812<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1813 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1814
1815</div>
1816
1817<!-- ======================================================================= -->
1818<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1819
1820<div class="doc_text">
1821
1822<dl>
1823 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1824 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1825 constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1826
1827 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1828 <dd>Standard integers (such as '4') are constants of
1829 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1830 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1831
1832 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1833 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1834 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1835 notation (see below). The assembler requires the exact decimal value of a
1836 floating-point constant. For example, the assembler accepts 1.25 but
1837 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1838 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1839
1840 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1841 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1842 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1843</dl>
1844
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1845<p>The one non-intuitive notation for constants is the hexadecimal form of
1846 floating point constants. For example, the form '<tt>double
1847 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1848 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1849 constants are required (and the only time that they are generated by the
1850 disassembler) is when a floating point constant must be emitted but it cannot
1851 be represented as a decimal floating point number in a reasonable number of
1852 digits. For example, NaN's, infinities, and other special values are
1853 represented in their IEEE hexadecimal format so that assembly and disassembly
1854 do not cause any bits to change in the constants.</p>
1855
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1856<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1857 represented using the 16-digit form shown above (which matches the IEEE754
1858 representation for double); float values must, however, be exactly
1859 representable as IEE754 single precision. Hexadecimal format is always used
1860 for long double, and there are three forms of long double. The 80-bit format
1861 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1862 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1863 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1864 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1865 currently supported target uses this format. Long doubles will only work if
1866 they match the long double format on your target. All hexadecimal formats
1867 are big-endian (sign bit at the left).</p>
1868
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1869</div>
1870
1871<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1872<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1873<a name="aggregateconstants"></a> <!-- old anchor -->
1874<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1875</div>
1876
1877<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1878
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1879<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1880 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1881
1882<dl>
1883 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1884 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1885 type definitions (a comma separated list of elements, surrounded by braces
1886 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1887 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1888 Structure constants must have <a href="#t_struct">structure type</a>, and
1889 the number and types of elements must match those specified by the
1890 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1891
1892 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1893 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1894 definitions (a comma separated list of elements, surrounded by square
1895 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1896 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1897 the number and types of elements must match those specified by the
1898 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1899
1900 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1901 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1902 definitions (a comma separated list of elements, surrounded by
1903 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1904 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1905 have <a href="#t_vector">vector type</a>, and the number and types of
1906 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907
1908 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1909 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1910 value to zero of <em>any</em> type, including scalar and aggregate types.
1911 This is often used to avoid having to print large zero initializers
1912 (e.g. for large arrays) and is always exactly equivalent to using explicit
1913 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1914
1915 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1916 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1917 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1918 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1919 be interpreted as part of the instruction stream, metadata is a place to
1920 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1921</dl>
1922
1923</div>
1924
1925<!-- ======================================================================= -->
1926<div class="doc_subsection">
1927 <a name="globalconstants">Global Variable and Function Addresses</a>
1928</div>
1929
1930<div class="doc_text">
1931
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1932<p>The addresses of <a href="#globalvars">global variables</a>
1933 and <a href="#functionstructure">functions</a> are always implicitly valid
1934 (link-time) constants. These constants are explicitly referenced when
1935 the <a href="#identifiers">identifier for the global</a> is used and always
1936 have <a href="#t_pointer">pointer</a> type. For example, the following is a
1937 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1938
1939<div class="doc_code">
1940<pre>
1941@X = global i32 17
1942@Y = global i32 42
1943@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1944</pre>
1945</div>
1946
1947</div>
1948
1949<!-- ======================================================================= -->
1950<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1951<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1952
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1953<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has no
1954 specific value. Undefined values may be of any type and be used anywhere a
1955 constant is permitted.</p>
1956
1957<p>Undefined values indicate to the compiler that the program is well defined no
1958 matter what value is used, giving the compiler more freedom to optimize.</p>
1959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1960</div>
1961
1962<!-- ======================================================================= -->
1963<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1964</div>
1965
1966<div class="doc_text">
1967
1968<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1969 to be used as constants. Constant expressions may be of
1970 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
1971 operation that does not have side effects (e.g. load and call are not
1972 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1973
1974<dl>
1975 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1976 <dd>Truncate a constant to another type. The bit size of CST must be larger
1977 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1978
1979 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1980 <dd>Zero extend a constant to another type. The bit size of CST must be
1981 smaller or equal to the bit size of TYPE. Both types must be
1982 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983
1984 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1985 <dd>Sign extend a constant to another type. The bit size of CST must be
1986 smaller or equal to the bit size of TYPE. Both types must be
1987 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988
1989 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1990 <dd>Truncate a floating point constant to another floating point type. The
1991 size of CST must be larger than the size of TYPE. Both types must be
1992 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1993
1994 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1995 <dd>Floating point extend a constant to another type. The size of CST must be
1996 smaller or equal to the size of TYPE. Both types must be floating
1997 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1998
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1999 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2000 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2001 constant. TYPE must be a scalar or vector integer type. CST must be of
2002 scalar or vector floating point type. Both CST and TYPE must be scalars,
2003 or vectors of the same number of elements. If the value won't fit in the
2004 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2005
2006 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2007 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2008 constant. TYPE must be a scalar or vector integer type. CST must be of
2009 scalar or vector floating point type. Both CST and TYPE must be scalars,
2010 or vectors of the same number of elements. If the value won't fit in the
2011 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2012
2013 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2014 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2015 constant. TYPE must be a scalar or vector floating point type. CST must be
2016 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2017 vectors of the same number of elements. If the value won't fit in the
2018 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2019
2020 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2021 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2022 constant. TYPE must be a scalar or vector floating point type. CST must be
2023 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2024 vectors of the same number of elements. If the value won't fit in the
2025 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2026
2027 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2028 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2029 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2030 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2031 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2032
2033 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2034 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2035 type. CST must be of integer type. The CST value is zero extended,
2036 truncated, or unchanged to make it fit in a pointer size. This one is
2037 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2038
2039 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2040 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2041 are the same as those for the <a href="#i_bitcast">bitcast
2042 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2043
2044 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2045 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2046 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2047 instruction, the index list may have zero or more indexes, which are
2048 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2049
2050 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2051 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2052
2053 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2054 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2055
2056 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2057 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2058
2059 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2060 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2061 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2062
2063 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2064 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2065 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2066
2067 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2068 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2069 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2070
2071 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2072 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2073 be any of the <a href="#binaryops">binary</a>
2074 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2075 on operands are the same as those for the corresponding instruction
2076 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2077</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2079</div>
2080
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2081<!-- ======================================================================= -->
2082<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2083</div>
2084
2085<div class="doc_text">
2086
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2087<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2088 stream without affecting the behaviour of the program. There are two
2089 metadata primitives, strings and nodes. All metadata has the
2090 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2091 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2092
2093<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2094 any character by escaping non-printable characters with "\xx" where "xx" is
2095 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2096
2097<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2098 (a comma separated list of elements, surrounded by braces and preceeded by an
2099 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2100 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2101
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2102<p>A metadata node will attempt to track changes to the values it holds. In the
2103 event that a value is deleted, it will be replaced with a typeless
2104 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2105
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2106<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2107 the program that isn't available in the instructions, or that isn't easily
2108 computable. Similarly, the code generator may expect a certain metadata
2109 format to be used to express debugging information.</p>
2110
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2111</div>
2112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2113<!-- *********************************************************************** -->
2114<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2115<!-- *********************************************************************** -->
2116
2117<!-- ======================================================================= -->
2118<div class="doc_subsection">
2119<a name="inlineasm">Inline Assembler Expressions</a>
2120</div>
2121
2122<div class="doc_text">
2123
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2124<p>LLVM supports inline assembler expressions (as opposed
2125 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2126 a special value. This value represents the inline assembler as a string
2127 (containing the instructions to emit), a list of operand constraints (stored
2128 as a string), and a flag that indicates whether or not the inline asm
2129 expression has side effects. An example inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2130
2131<div class="doc_code">
2132<pre>
2133i32 (i32) asm "bswap $0", "=r,r"
2134</pre>
2135</div>
2136
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2137<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2138 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2139 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2140
2141<div class="doc_code">
2142<pre>
2143%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2144</pre>
2145</div>
2146
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2147<p>Inline asms with side effects not visible in the constraint list must be
2148 marked as having side effects. This is done through the use of the
2149 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2150
2151<div class="doc_code">
2152<pre>
2153call void asm sideeffect "eieio", ""()
2154</pre>
2155</div>
2156
2157<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2158 documented here. Constraints on what can be done (e.g. duplication, moving,
2159 etc need to be documented). This is probably best done by reference to
2160 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2161
2162</div>
2163
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2164
2165<!-- *********************************************************************** -->
2166<div class="doc_section">
2167 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2168</div>
2169<!-- *********************************************************************** -->
2170
2171<p>LLVM has a number of "magic" global variables that contain data that affect
2172code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2173of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2174section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2175by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2176
2177<!-- ======================================================================= -->
2178<div class="doc_subsection">
2179<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2180</div>
2181
2182<div class="doc_text">
2183
2184<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2185href="#linkage_appending">appending linkage</a>. This array contains a list of
2186pointers to global variables and functions which may optionally have a pointer
2187cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2188
2189<pre>
2190 @X = global i8 4
2191 @Y = global i32 123
2192
2193 @llvm.used = appending global [2 x i8*] [
2194 i8* @X,
2195 i8* bitcast (i32* @Y to i8*)
2196 ], section "llvm.metadata"
2197</pre>
2198
2199<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2200compiler, assembler, and linker are required to treat the symbol as if there is
2201a reference to the global that it cannot see. For example, if a variable has
2202internal linkage and no references other than that from the <tt>@llvm.used</tt>
2203list, it cannot be deleted. This is commonly used to represent references from
2204inline asms and other things the compiler cannot "see", and corresponds to
2205"attribute((used))" in GNU C.</p>
2206
2207<p>On some targets, the code generator must emit a directive to the assembler or
2208object file to prevent the assembler and linker from molesting the symbol.</p>
2209
2210</div>
2211
2212<!-- ======================================================================= -->
2213<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2214<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2215</div>
2216
2217<div class="doc_text">
2218
2219<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2220<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2221touching the symbol. On targets that support it, this allows an intelligent
2222linker to optimize references to the symbol without being impeded as it would be
2223by <tt>@llvm.used</tt>.</p>
2224
2225<p>This is a rare construct that should only be used in rare circumstances, and
2226should not be exposed to source languages.</p>
2227
2228</div>
2229
2230<!-- ======================================================================= -->
2231<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2232<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2233</div>
2234
2235<div class="doc_text">
2236
2237<p>TODO: Describe this.</p>
2238
2239</div>
2240
2241<!-- ======================================================================= -->
2242<div class="doc_subsection">
2243<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2244</div>
2245
2246<div class="doc_text">
2247
2248<p>TODO: Describe this.</p>
2249
2250</div>
2251
2252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2253<!-- *********************************************************************** -->
2254<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2255<!-- *********************************************************************** -->
2256
2257<div class="doc_text">
2258
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2259<p>The LLVM instruction set consists of several different classifications of
2260 instructions: <a href="#terminators">terminator
2261 instructions</a>, <a href="#binaryops">binary instructions</a>,
2262 <a href="#bitwiseops">bitwise binary instructions</a>,
2263 <a href="#memoryops">memory instructions</a>, and
2264 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2265
2266</div>
2267
2268<!-- ======================================================================= -->
2269<div class="doc_subsection"> <a name="terminators">Terminator
2270Instructions</a> </div>
2271
2272<div class="doc_text">
2273
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2274<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2275 in a program ends with a "Terminator" instruction, which indicates which
2276 block should be executed after the current block is finished. These
2277 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2278 control flow, not values (the one exception being the
2279 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2280
2281<p>There are six different terminator instructions: the
2282 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2283 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2284 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
2285 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2286 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2287 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2288
2289</div>
2290
2291<!-- _______________________________________________________________________ -->
2292<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2293Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2295<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2296
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2297<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2298<pre>
2299 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]2300 ret void <i>; Return from void function</i>
2301</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2303<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2304<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2305 a value) from a function back to the caller.</p>
2306
2307<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2308 value and then causes control flow, and one that just causes control flow to
2309 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2312<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2313 return value. The type of the return value must be a
2314 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2315
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2316<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2317 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2318 value or a return value with a type that does not match its type, or if it
2319 has a void return type and contains a '<tt>ret</tt>' instruction with a
2320 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2322<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2323<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2324 the calling function's context. If the caller is a
2325 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2326 instruction after the call. If the caller was an
2327 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2328 the beginning of the "normal" destination block. If the instruction returns
2329 a value, that value shall set the call or invoke instruction's return
2330 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2332<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2333<pre>
2334 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2335 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2336 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]2337</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2338
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2339<p>Note that the code generator does not yet fully support large
2340 return values. The specific sizes that are currently supported are
2341 dependent on the target. For integers, on 32-bit targets the limit
2342 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2343 For aggregate types, the current limits are dependent on the element
2344 types; for example targets are often limited to 2 total integer
2345 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2346
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2347</div>
2348<!-- _______________________________________________________________________ -->
2349<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2351<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2354<pre>
2355 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]2356</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2358<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2359<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2360 different basic block in the current function. There are two forms of this
2361 instruction, corresponding to a conditional branch and an unconditional
2362 branch.</p>
2363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2365<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2366 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2367 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2368 target.</p>
2369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2370<h5>Semantics:</h5>
2371<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2372 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2373 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2374 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2376<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2377<pre>
2378Test:
2379 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2380 br i1 %cond, label %IfEqual, label %IfUnequal
2381IfEqual:
2382 <a href="#i_ret">ret</a> i32 1
2383IfUnequal:
2384 <a href="#i_ret">ret</a> i32 0
2385</pre>
2386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389<!-- _______________________________________________________________________ -->
2390<div class="doc_subsubsection">
2391 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2392</div>
2393
2394<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2395
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2396<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2397<pre>
2398 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2399</pre>
2400
2401<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2402<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]2403 several different places. It is a generalization of the '<tt>br</tt>'
2404 instruction, allowing a branch to occur to one of many possible
2405 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2406
2407<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2408<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2409 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2410 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2411 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2412
2413<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2415 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2416 is searched for the given value. If the value is found, control flow is
2417 transfered to the corresponding destination; otherwise, control flow is
2418 transfered to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2419
2420<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2422 <tt>switch</tt> instruction, this instruction may be code generated in
2423 different ways. For example, it could be generated as a series of chained
2424 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2425
2426<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2427<pre>
2428 <i>; Emulate a conditional br instruction</i>
2429 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2430 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2431
2432 <i>; Emulate an unconditional br instruction</i>
2433 switch i32 0, label %dest [ ]
2434
2435 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2436 switch i32 %val, label %otherwise [ i32 0, label %onzero
2437 i32 1, label %onone
2438 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2439</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2441</div>
2442
2443<!-- _______________________________________________________________________ -->
2444<div class="doc_subsubsection">
2445 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2446</div>
2447
2448<div class="doc_text">
2449
2450<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2451<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2452 &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]2453 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2454</pre>
2455
2456<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2457<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2458 function, with the possibility of control flow transfer to either the
2459 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2460 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2461 control flow will return to the "normal" label. If the callee (or any
2462 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2463 instruction, control is interrupted and continued at the dynamically nearest
2464 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2465
2466<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2467<p>This instruction requires several arguments:</p>
2468
2469<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2470 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2471 convention</a> the call should use. If none is specified, the call
2472 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2473
2474 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2475 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2476 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2478 <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]2479 function value being invoked. In most cases, this is a direct function
2480 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2481 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482
2483 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2484 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2485
2486 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2487 signature argument types. If the function signature indicates the
2488 function accepts a variable number of arguments, the extra arguments can
2489 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2490
2491 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2492 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2493
2494 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2495 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2497 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2498 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2499 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2500</ol>
2501
2502<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2503<p>This instruction is designed to operate as a standard
2504 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2505 primary difference is that it establishes an association with a label, which
2506 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2507
2508<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2509 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2510 exception. Additionally, this is important for implementation of
2511 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2513<p>For the purposes of the SSA form, the definition of the value returned by the
2514 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2515 block to the "normal" label. If the callee unwinds then no return value is
2516 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2518<h5>Example:</h5>
2519<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2520 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2521 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2522 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2523 unwind label %TestCleanup <i>; {i32}:retval set</i>
2524</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2526</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2527
2528<!-- _______________________________________________________________________ -->
2529
2530<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2531Instruction</a> </div>
2532
2533<div class="doc_text">
2534
2535<h5>Syntax:</h5>
2536<pre>
2537 unwind
2538</pre>
2539
2540<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2541<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2542 at the first callee in the dynamic call stack which used
2543 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2544 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545
2546<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2547<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2548 immediately halt. The dynamic call stack is then searched for the
2549 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2550 Once found, execution continues at the "exceptional" destination block
2551 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2552 instruction in the dynamic call chain, undefined behavior results.</p>
2553
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2554</div>
2555
2556<!-- _______________________________________________________________________ -->
2557
2558<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2559Instruction</a> </div>
2560
2561<div class="doc_text">
2562
2563<h5>Syntax:</h5>
2564<pre>
2565 unreachable
2566</pre>
2567
2568<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2569<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2570 instruction is used to inform the optimizer that a particular portion of the
2571 code is not reachable. This can be used to indicate that the code after a
2572 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2573
2574<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577</div>
2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579<!-- ======================================================================= -->
2580<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2583
2584<p>Binary operators are used to do most of the computation in a program. They
2585 require two operands of the same type, execute an operation on them, and
2586 produce a single value. The operands might represent multiple data, as is
2587 the case with the <a href="#t_vector">vector</a> data type. The result value
2588 has the same type as its operands.</p>
2589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2592</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2595<div class="doc_subsubsection">
2596 <a name="i_add">'<tt>add</tt>' Instruction</a>
2597</div>
2598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2599<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2601<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2602<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2603 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2606<h5>Overview:</h5>
2607<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2608
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2609<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2610<p>The two arguments to the '<tt>add</tt>' instruction must
2611 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2612 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2615<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2616
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2617<p>If the sum has unsigned overflow, the result returned is the mathematical
2618 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]2619
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2620<p>Because LLVM integers use a two's complement representation, this instruction
2621 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2623<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2624<pre>
2625 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2626</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2630<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2631<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2632 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2633</div>
2634
2635<div class="doc_text">
2636
2637<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2638<pre>
2639 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2640</pre>
2641
2642<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2643<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2644
2645<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2646<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2647 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2648 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2649
2650<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2651<p>The value produced is the floating point sum of the two operands.</p>
2652
2653<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2654<pre>
2655 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2656</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2657
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2658</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2659
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2660<!-- _______________________________________________________________________ -->
2661<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2662 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2663</div>
2664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2665<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2666
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2668<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2669 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2671
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2672<h5>Overview:</h5>
2673<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2674 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2675
2676<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2677 '<tt>neg</tt>' instruction present in most other intermediate
2678 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2681<p>The two arguments to the '<tt>sub</tt>' instruction must
2682 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2683 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2686<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2687
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2688<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2689 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2690 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2691
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2692<p>Because LLVM integers use a two's complement representation, this instruction
2693 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695<h5>Example:</h5>
2696<pre>
2697 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2698 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2699</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2701</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2704<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2705 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2706</div>
2707
2708<div class="doc_text">
2709
2710<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2711<pre>
2712 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2713</pre>
2714
2715<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2716<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2717 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2718
2719<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2720 '<tt>fneg</tt>' instruction present in most other intermediate
2721 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2722
2723<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2724<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2725 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2726 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2727
2728<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2729<p>The value produced is the floating point difference of the two operands.</p>
2730
2731<h5>Example:</h5>
2732<pre>
2733 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2734 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2735</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2736
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2737</div>
2738
2739<!-- _______________________________________________________________________ -->
2740<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2741 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2742</div>
2743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2745
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2746<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2747<pre>
2748 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2749</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2751<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2752<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2754<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2755<p>The two arguments to the '<tt>mul</tt>' instruction must
2756 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2757 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2759<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2760<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2761
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2762<p>If the result of the multiplication has unsigned overflow, the result
2763 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2764 width of the result.</p>
2765
2766<p>Because LLVM integers use a two's complement representation, and the result
2767 is the same width as the operands, this instruction returns the correct
2768 result for both signed and unsigned integers. If a full product
2769 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2770 be sign-extended or zero-extended as appropriate to the width of the full
2771 product.</p>
2772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2774<pre>
2775 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2776</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2778</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2779
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2780<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2781<div class="doc_subsubsection">
2782 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2783</div>
2784
2785<div class="doc_text">
2786
2787<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2788<pre>
2789 &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]2790</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2791
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2792<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2793<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2794
2795<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2796<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2797 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2798 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2799
2800<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2801<p>The value produced is the floating point product of the two operands.</p>
2802
2803<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2804<pre>
2805 &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]2806</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2807
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2808</div>
2809
2810<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2811<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2812</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2814<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2815
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2816<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2817<pre>
2818 &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]2819</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2820
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2821<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2822<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2824<h5>Arguments:</h5>
2825<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2826 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2827 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2828
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2829<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2830<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2831
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2832<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2833 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2834
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2835<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2837<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2838<pre>
2839 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2842</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844<!-- _______________________________________________________________________ -->
2845<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2846</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2850<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2851<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2852 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2853</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2856<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2859<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2860 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2861 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2863<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2864<p>The value produced is the signed integer quotient of the two operands rounded
2865 towards zero.</p>
2866
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2867<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2868 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2869
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2870<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2871 undefined behavior; this is a rare case, but can occur, for example, by doing
2872 a 32-bit division of -2147483648 by -1.</p>
2873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2874<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2875<pre>
2876 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2877</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2879</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2881<!-- _______________________________________________________________________ -->
2882<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2883Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2885<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2887<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2888<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2889 &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]2890</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2891
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2892<h5>Overview:</h5>
2893<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2895<h5>Arguments:</h5>
2896<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2897 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2898 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2900<h5>Semantics:</h5>
2901<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2904<pre>
2905 &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]2906</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2908</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2910<!-- _______________________________________________________________________ -->
2911<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2912</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2914<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2916<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2917<pre>
2918 &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]2919</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2921<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2922<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
2923 division of its two arguments.</p>
2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2926<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2927 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2928 values. Both arguments must have identical types.</p>
2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930<h5>Semantics:</h5>
2931<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2932 This instruction always performs an unsigned division to get the
2933 remainder.</p>
2934
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2935<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2936 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2937
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2938<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2940<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2941<pre>
2942 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2943</pre>
2944
2945</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2946
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2948<div class="doc_subsubsection">
2949 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2950</div>
2951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2952<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2954<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2955<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2956 &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]2957</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2958
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2960<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
2961 division of its two operands. This instruction can also take
2962 <a href="#t_vector">vector</a> versions of the values in which case the
2963 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965<h5>Arguments:</h5>
2966<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2967 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2968 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2969
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2970<h5>Semantics:</h5>
2971<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2972 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2973 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
2974 a value. For more information about the difference,
2975 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2976 Math Forum</a>. For a table of how this is implemented in various languages,
2977 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2978 Wikipedia: modulo operation</a>.</p>
2979
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2980<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2981 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2982
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2983<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2984 Overflow also leads to undefined behavior; this is a rare case, but can
2985 occur, for example, by taking the remainder of a 32-bit division of
2986 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
2987 lets srem be implemented using instructions that return both the result of
2988 the division and the remainder.)</p>
2989
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2990<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2991<pre>
2992 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2993</pre>
2994
2995</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2998<div class="doc_subsubsection">
2999 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3001<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +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; = 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]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>frem</tt>' instruction returns the remainder from the division of
3010 its two operands.</p>
3011
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3012<h5>Arguments:</h5>
3013<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3014 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3015 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3016
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3017<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3018<p>This instruction returns the <i>remainder</i> of a division. The remainder
3019 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3021<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3022<pre>
3023 &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]3024</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3026</div>
3027
3028<!-- ======================================================================= -->
3029<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3030Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3032<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3033
3034<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3035 program. They are generally very efficient instructions and can commonly be
3036 strength reduced from other instructions. They require two operands of the
3037 same type, execute an operation on them, and produce a single value. The
3038 resulting value is the same type as its operands.</p>
3039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3040</div>
3041
3042<!-- _______________________________________________________________________ -->
3043<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3044Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3046<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3048<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3049<pre>
3050 &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]3051</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3053<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3054<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3055 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3057<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3058<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3059 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3060 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3062<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3063<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3064 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3065 is (statically or dynamically) negative or equal to or larger than the number
3066 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3067 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3068 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3069
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070<h5>Example:</h5>
3071<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3072 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3073 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3074 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3075 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3076 &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]3077</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3079</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3081<!-- _______________________________________________________________________ -->
3082<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3083Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3085<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3087<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088<pre>
3089 &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]3090</pre>
3091
3092<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3093<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3094 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3095
3096<h5>Arguments:</h5>
3097<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3098 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3099 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3100
3101<h5>Semantics:</h5>
3102<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3103 significant bits of the result will be filled with zero bits after the shift.
3104 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3105 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3106 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3107 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108
3109<h5>Example:</h5>
3110<pre>
3111 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3112 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3113 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3114 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3115 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3116 &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]3117</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3118
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3119</div>
3120
3121<!-- _______________________________________________________________________ -->
3122<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3123Instruction</a> </div>
3124<div class="doc_text">
3125
3126<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3127<pre>
3128 &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]3129</pre>
3130
3131<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3132<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3133 operand shifted to the right a specified number of bits with sign
3134 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3135
3136<h5>Arguments:</h5>
3137<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3138 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3139 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3140
3141<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3142<p>This instruction always performs an arithmetic shift right operation, The
3143 most significant bits of the result will be filled with the sign bit
3144 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3145 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3146 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3147 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3148
3149<h5>Example:</h5>
3150<pre>
3151 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3152 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3153 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3154 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3155 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3156 &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]3157</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3159</div>
3160
3161<!-- _______________________________________________________________________ -->
3162<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3163Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3164
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3165<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3169 &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]3170</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3173<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3174 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3176<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3177<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3179 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3181<h5>Semantics:</h5>
3182<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3183
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3184<table border="1" cellspacing="0" cellpadding="4">
3185 <tbody>
3186 <tr>
3187 <td>In0</td>
3188 <td>In1</td>
3189 <td>Out</td>
3190 </tr>
3191 <tr>
3192 <td>0</td>
3193 <td>0</td>
3194 <td>0</td>
3195 </tr>
3196 <tr>
3197 <td>0</td>
3198 <td>1</td>
3199 <td>0</td>
3200 </tr>
3201 <tr>
3202 <td>1</td>
3203 <td>0</td>
3204 <td>0</td>
3205 </tr>
3206 <tr>
3207 <td>1</td>
3208 <td>1</td>
3209 <td>1</td>
3210 </tr>
3211 </tbody>
3212</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3213
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3214<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3215<pre>
3216 &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]3217 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3218 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3219</pre>
3220</div>
3221<!-- _______________________________________________________________________ -->
3222<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3223
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3224<div class="doc_text">
3225
3226<h5>Syntax:</h5>
3227<pre>
3228 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3229</pre>
3230
3231<h5>Overview:</h5>
3232<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3233 two operands.</p>
3234
3235<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3236<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3237 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3238 values. Both arguments must have identical types.</p>
3239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240<h5>Semantics:</h5>
3241<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243<table border="1" cellspacing="0" cellpadding="4">
3244 <tbody>
3245 <tr>
3246 <td>In0</td>
3247 <td>In1</td>
3248 <td>Out</td>
3249 </tr>
3250 <tr>
3251 <td>0</td>
3252 <td>0</td>
3253 <td>0</td>
3254 </tr>
3255 <tr>
3256 <td>0</td>
3257 <td>1</td>
3258 <td>1</td>
3259 </tr>
3260 <tr>
3261 <td>1</td>
3262 <td>0</td>
3263 <td>1</td>
3264 </tr>
3265 <tr>
3266 <td>1</td>
3267 <td>1</td>
3268 <td>1</td>
3269 </tr>
3270 </tbody>
3271</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3272
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3273<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3274<pre>
3275 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3276 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3277 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3278</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3280</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3282<!-- _______________________________________________________________________ -->
3283<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3284Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3285
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3286<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3288<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3289<pre>
3290 &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]3291</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3293<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3294<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3295 its two operands. The <tt>xor</tt> is used to implement the "one's
3296 complement" operation, which is the "~" operator in C.</p>
3297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3299<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3300 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3301 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3303<h5>Semantics:</h5>
3304<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3306<table border="1" cellspacing="0" cellpadding="4">
3307 <tbody>
3308 <tr>
3309 <td>In0</td>
3310 <td>In1</td>
3311 <td>Out</td>
3312 </tr>
3313 <tr>
3314 <td>0</td>
3315 <td>0</td>
3316 <td>0</td>
3317 </tr>
3318 <tr>
3319 <td>0</td>
3320 <td>1</td>
3321 <td>1</td>
3322 </tr>
3323 <tr>
3324 <td>1</td>
3325 <td>0</td>
3326 <td>1</td>
3327 </tr>
3328 <tr>
3329 <td>1</td>
3330 <td>1</td>
3331 <td>0</td>
3332 </tr>
3333 </tbody>
3334</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3336<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3337<pre>
3338 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3340 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3341 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3342</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344</div>
3345
3346<!-- ======================================================================= -->
3347<div class="doc_subsection">
3348 <a name="vectorops">Vector Operations</a>
3349</div>
3350
3351<div class="doc_text">
3352
3353<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3354 target-independent manner. These instructions cover the element-access and
3355 vector-specific operations needed to process vectors effectively. While LLVM
3356 does directly support these vector operations, many sophisticated algorithms
3357 will want to use target-specific intrinsics to take full advantage of a
3358 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359
3360</div>
3361
3362<!-- _______________________________________________________________________ -->
3363<div class="doc_subsubsection">
3364 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3365</div>
3366
3367<div class="doc_text">
3368
3369<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3370<pre>
3371 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3372</pre>
3373
3374<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3375<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3376 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377
3378
3379<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3380<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3381 of <a href="#t_vector">vector</a> type. The second operand is an index
3382 indicating the position from which to extract the element. The index may be
3383 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3384
3385<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3386<p>The result is a scalar of the same type as the element type of
3387 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3388 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3389 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390
3391<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3392<pre>
3393 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3394</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3395
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3397
3398<!-- _______________________________________________________________________ -->
3399<div class="doc_subsubsection">
3400 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3401</div>
3402
3403<div class="doc_text">
3404
3405<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3407 &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]3408</pre>
3409
3410<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3411<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3412 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3413
3414<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3415<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3416 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3417 whose type must equal the element type of the first operand. The third
3418 operand is an index indicating the position at which to insert the value.
3419 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3420
3421<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3422<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3423 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3424 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3425 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426
3427<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3428<pre>
3429 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3430</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3432</div>
3433
3434<!-- _______________________________________________________________________ -->
3435<div class="doc_subsubsection">
3436 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3437</div>
3438
3439<div class="doc_text">
3440
3441<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3443 &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]3444</pre>
3445
3446<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3447<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3448 from two input vectors, returning a vector with the same element type as the
3449 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450
3451<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3452<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3453 with types that match each other. The third argument is a shuffle mask whose
3454 element type is always 'i32'. The result of the instruction is a vector
3455 whose length is the same as the shuffle mask and whose element type is the
3456 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3457
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3458<p>The shuffle mask operand is required to be a constant vector with either
3459 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3460
3461<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3462<p>The elements of the two input vectors are numbered from left to right across
3463 both of the vectors. The shuffle mask operand specifies, for each element of
3464 the result vector, which element of the two input vectors the result element
3465 gets. The element selector may be undef (meaning "don't care") and the
3466 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3467
3468<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3469<pre>
3470 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3471 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3472 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3473 &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]3474 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3475 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3476 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3477 &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]3478</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3479
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3480</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3481
3482<!-- ======================================================================= -->
3483<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3484 <a name="aggregateops">Aggregate Operations</a>
3485</div>
3486
3487<div class="doc_text">
3488
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3489<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3490
3491</div>
3492
3493<!-- _______________________________________________________________________ -->
3494<div class="doc_subsubsection">
3495 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3496</div>
3497
3498<div class="doc_text">
3499
3500<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3501<pre>
3502 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3503</pre>
3504
3505<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3506<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3507 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3508
3509<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3510<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3511 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3512 operands are constant indices to specify which value to extract in a similar
3513 manner as indices in a
3514 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3515
3516<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3517<p>The result is the value at the position in the aggregate specified by the
3518 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3519
3520<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3521<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3522 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3523</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3524
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3525</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3526
3527<!-- _______________________________________________________________________ -->
3528<div class="doc_subsubsection">
3529 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3530</div>
3531
3532<div class="doc_text">
3533
3534<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3535<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3536 &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]3537</pre>
3538
3539<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3540<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3541 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3542
3543
3544<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3545<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3546 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3547 second operand is a first-class value to insert. The following operands are
3548 constant indices indicating the position at which to insert the value in a
3549 similar manner as indices in a
3550 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3551 value to insert must have the same type as the value identified by the
3552 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3553
3554<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3555<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3556 that of <tt>val</tt> except that the value at the position specified by the
3557 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3558
3559<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3560<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3561 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3562</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3563
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3564</div>
3565
3566
3567<!-- ======================================================================= -->
3568<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3569 <a name="memoryops">Memory Access and Addressing Operations</a>
3570</div>
3571
3572<div class="doc_text">
3573
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3574<p>A key design point of an SSA-based representation is how it represents
3575 memory. In LLVM, no memory locations are in SSA form, which makes things
3576 very simple. This section describes how to read, write, allocate, and free
3577 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3578
3579</div>
3580
3581<!-- _______________________________________________________________________ -->
3582<div class="doc_subsubsection">
3583 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3584</div>
3585
3586<div class="doc_text">
3587
3588<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3589<pre>
3590 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3591</pre>
3592
3593<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3594<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3595 returns a pointer to it. The object is always allocated in the generic
3596 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3597
3598<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3599<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3601 system and returns a pointer of the appropriate type to the program. If
3602 "NumElements" is specified, it is the number of elements allocated, otherwise
3603 "NumElements" is defaulted to be one. If a constant alignment is specified,
3604 the value result of the allocation is guaranteed to be aligned to at least
3605 that boundary. If not specified, or if zero, the target can choose to align
3606 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3607
3608<p>'<tt>type</tt>' must be a sized type.</p>
3609
3610<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3611<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3612 pointer is returned. The result of a zero byte allocation is undefined. The
3613 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3614
3615<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3616<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3617 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618
3619 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3620 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3621 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3622 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3623 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3624</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3625
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3626<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628</div>
3629
3630<!-- _______________________________________________________________________ -->
3631<div class="doc_subsubsection">
3632 <a name="i_free">'<tt>free</tt>' Instruction</a>
3633</div>
3634
3635<div class="doc_text">
3636
3637<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3638<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3639 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640</pre>
3641
3642<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3643<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3644 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3645
3646<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3647<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3648 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3649
3650<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3651<p>Access to the memory pointed to by the pointer is no longer defined after
3652 this instruction executes. If the pointer is null, the operation is a
3653 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3654
3655<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3656<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3657 %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]3658 free [4 x i8]* %array
3659</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3661</div>
3662
3663<!-- _______________________________________________________________________ -->
3664<div class="doc_subsubsection">
3665 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3666</div>
3667
3668<div class="doc_text">
3669
3670<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671<pre>
3672 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3673</pre>
3674
3675<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3676<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3677 currently executing function, to be automatically released when this function
3678 returns to its caller. The object is always allocated in the generic address
3679 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3680
3681<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3682<p>The '<tt>alloca</tt>' instruction
3683 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3684 runtime stack, returning a pointer of the appropriate type to the program.
3685 If "NumElements" is specified, it is the number of elements allocated,
3686 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3687 specified, the value result of the allocation is guaranteed to be aligned to
3688 at least that boundary. If not specified, or if zero, the target can choose
3689 to align the allocation on any convenient boundary compatible with the
3690 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3691
3692<p>'<tt>type</tt>' may be any sized type.</p>
3693
3694<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3695<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3696 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3697 memory is automatically released when the function returns. The
3698 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3699 variables that must have an address available. When the function returns
3700 (either with the <tt><a href="#i_ret">ret</a></tt>
3701 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3702 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3703
3704<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3706 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3707 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3708 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3709 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3711
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712</div>
3713
3714<!-- _______________________________________________________________________ -->
3715<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3716Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3718<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3720<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3721<pre>
3722 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3723 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3724</pre>
3725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3726<h5>Overview:</h5>
3727<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3729<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3730<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3731 from which to load. The pointer must point to
3732 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3733 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3734 number or order of execution of this <tt>load</tt> with other
3735 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3736 instructions. </p>
3737
3738<p>The optional constant "align" argument specifies the alignment of the
3739 operation (that is, the alignment of the memory address). A value of 0 or an
3740 omitted "align" argument means that the operation has the preferential
3741 alignment for the target. It is the responsibility of the code emitter to
3742 ensure that the alignment information is correct. Overestimating the
3743 alignment results in an undefined behavior. Underestimating the alignment may
3744 produce less efficient code. An alignment of 1 is always safe.</p>
3745
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3747<p>The location of memory pointed to is loaded. If the value being loaded is of
3748 scalar type then the number of bytes read does not exceed the minimum number
3749 of bytes needed to hold all bits of the type. For example, loading an
3750 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3751 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3752 is undefined if the value was not originally written using a store of the
3753 same type.</p>
3754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3756<pre>
3757 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3758 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3759 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3760</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3764<!-- _______________________________________________________________________ -->
3765<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3766Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3770<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3771<pre>
3772 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]3773 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3774</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3775
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3776<h5>Overview:</h5>
3777<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3779<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3780<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3781 and an address at which to store it. The type of the
3782 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3783 the <a href="#t_firstclass">first class</a> type of the
3784 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3785 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3786 or order of execution of this <tt>store</tt> with other
3787 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3788 instructions.</p>
3789
3790<p>The optional constant "align" argument specifies the alignment of the
3791 operation (that is, the alignment of the memory address). A value of 0 or an
3792 omitted "align" argument means that the operation has the preferential
3793 alignment for the target. It is the responsibility of the code emitter to
3794 ensure that the alignment information is correct. Overestimating the
3795 alignment results in an undefined behavior. Underestimating the alignment may
3796 produce less efficient code. An alignment of 1 is always safe.</p>
3797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3798<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3799<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3800 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3801 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3802 does not exceed the minimum number of bytes needed to hold all bits of the
3803 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3804 writing a value of a type like <tt>i20</tt> with a size that is not an
3805 integral number of bytes, it is unspecified what happens to the extra bits
3806 that do not belong to the type, but they will typically be overwritten.</p>
3807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3808<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3809<pre>
3810 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3811 store i32 3, i32* %ptr <i>; yields {void}</i>
3812 %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]3813</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3815</div>
3816
3817<!-- _______________________________________________________________________ -->
3818<div class="doc_subsubsection">
3819 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3820</div>
3821
3822<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3824<h5>Syntax:</h5>
3825<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3826 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3827</pre>
3828
3829<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3830<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
3831 subelement of an aggregate data structure. It performs address calculation
3832 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3833
3834<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3835<p>The first argument is always a pointer, and forms the basis of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3836 calculation. The remaining arguments are indices, that indicate which of the
3837 elements of the aggregate object are indexed. The interpretation of each
3838 index is dependent on the type being indexed into. The first index always
3839 indexes the pointer value given as the first argument, the second index
3840 indexes a value of the type pointed to (not necessarily the value directly
3841 pointed to, since the first index can be non-zero), etc. The first type
3842 indexed into must be a pointer value, subsequent types can be arrays, vectors
3843 and structs. Note that subsequent types being indexed into can never be
3844 pointers, since that would require loading the pointer before continuing
3845 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3846
3847<p>The type of each index argument depends on the type it is indexing into.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3848 When indexing into a (packed) structure, only <tt>i32</tt> integer
3849 <b>constants</b> are allowed. When indexing into an array, pointer or
3850 vector, integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3851
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3852<p>For example, let's consider a C code fragment and how it gets compiled to
3853 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3854
3855<div class="doc_code">
3856<pre>
3857struct RT {
3858 char A;
3859 int B[10][20];
3860 char C;
3861};
3862struct ST {
3863 int X;
3864 double Y;
3865 struct RT Z;
3866};
3867
3868int *foo(struct ST *s) {
3869 return &amp;s[1].Z.B[5][13];
3870}
3871</pre>
3872</div>
3873
3874<p>The LLVM code generated by the GCC frontend is:</p>
3875
3876<div class="doc_code">
3877<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3878%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3879%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3880
3881define i32* %foo(%ST* %s) {
3882entry:
3883 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3884 ret i32* %reg
3885}
3886</pre>
3887</div>
3888
3889<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3890<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]3891 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3892 }</tt>' type, a structure. The second index indexes into the third element
3893 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3894 i8 }</tt>' type, another structure. The third index indexes into the second
3895 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3896 array. The two dimensions of the array are subscripted into, yielding an
3897 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
3898 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3899
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3900<p>Note that it is perfectly legal to index partially through a structure,
3901 returning a pointer to an inner element. Because of this, the LLVM code for
3902 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3903
3904<pre>
3905 define i32* %foo(%ST* %s) {
3906 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3907 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3908 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3909 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3910 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3911 ret i32* %t5
3912 }
3913</pre>
3914
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3915<p>Note that it is undefined to access an array out of bounds: array and pointer
3916 indexes must always be within the defined bounds of the array type when
3917 accessed with an instruction that dereferences the pointer (e.g. a load or
3918 store instruction). The one exception for this rule is zero length arrays.
3919 These arrays are defined to be accessible as variable length arrays, which
3920 requires access beyond the zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3921
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3922<p>The getelementptr instruction is often confusing. For some more insight into
3923 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3924
3925<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3926<pre>
3927 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3928 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3929 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3930 %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]3931 <i>; yields i8*:eptr</i>
3932 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3933 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3934 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3935</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3937</div>
3938
3939<!-- ======================================================================= -->
3940<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3941</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3943<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3945<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3946 which all take a single operand and a type. They perform various bit
3947 conversions on the operand.</p>
3948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949</div>
3950
3951<!-- _______________________________________________________________________ -->
3952<div class="doc_subsubsection">
3953 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3954</div>
3955<div class="doc_text">
3956
3957<h5>Syntax:</h5>
3958<pre>
3959 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3960</pre>
3961
3962<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3963<p>The '<tt>trunc</tt>' instruction truncates its operand to the
3964 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965
3966<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3967<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3968 be an <a href="#t_integer">integer</a> type, and a type that specifies the
3969 size and type of the result, which must be
3970 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
3971 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
3972 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3973
3974<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3975<p>The '<tt>trunc</tt>' instruction truncates the high order bits
3976 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
3977 source size must be larger than the destination size, <tt>trunc</tt> cannot
3978 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979
3980<h5>Example:</h5>
3981<pre>
3982 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3983 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3984 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3985</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3987</div>
3988
3989<!-- _______________________________________________________________________ -->
3990<div class="doc_subsubsection">
3991 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3992</div>
3993<div class="doc_text">
3994
3995<h5>Syntax:</h5>
3996<pre>
3997 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3998</pre>
3999
4000<h5>Overview:</h5>
4001<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4002 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4003
4004
4005<h5>Arguments:</h5>
4006<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]4007 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4008 also be of <a href="#t_integer">integer</a> type. The bit size of the
4009 <tt>value</tt> must be smaller than the bit size of the destination type,
4010 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4011
4012<h5>Semantics:</h5>
4013<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]4014 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015
4016<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4017
4018<h5>Example:</h5>
4019<pre>
4020 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4021 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4022</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4024</div>
4025
4026<!-- _______________________________________________________________________ -->
4027<div class="doc_subsubsection">
4028 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4029</div>
4030<div class="doc_text">
4031
4032<h5>Syntax:</h5>
4033<pre>
4034 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4035</pre>
4036
4037<h5>Overview:</h5>
4038<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4039
4040<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4041<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4042 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4043 also be of <a href="#t_integer">integer</a> type. The bit size of the
4044 <tt>value</tt> must be smaller than the bit size of the destination type,
4045 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046
4047<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4048<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4049 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4050 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051
4052<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4053
4054<h5>Example:</h5>
4055<pre>
4056 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4057 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4058</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4059
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060</div>
4061
4062<!-- _______________________________________________________________________ -->
4063<div class="doc_subsubsection">
4064 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4065</div>
4066
4067<div class="doc_text">
4068
4069<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070<pre>
4071 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4072</pre>
4073
4074<h5>Overview:</h5>
4075<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4076 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4077
4078<h5>Arguments:</h5>
4079<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4080 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4081 to cast it to. The size of <tt>value</tt> must be larger than the size of
4082 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4083 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084
4085<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4086<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4087 <a href="#t_floating">floating point</a> type to a smaller
4088 <a href="#t_floating">floating point</a> type. If the value cannot fit
4089 within the destination type, <tt>ty2</tt>, then the results are
4090 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4091
4092<h5>Example:</h5>
4093<pre>
4094 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4095 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4096</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4098</div>
4099
4100<!-- _______________________________________________________________________ -->
4101<div class="doc_subsubsection">
4102 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4103</div>
4104<div class="doc_text">
4105
4106<h5>Syntax:</h5>
4107<pre>
4108 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4109</pre>
4110
4111<h5>Overview:</h5>
4112<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]4113 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114
4115<h5>Arguments:</h5>
4116<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4117 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4118 a <a href="#t_floating">floating point</a> type to cast it to. The source
4119 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120
4121<h5>Semantics:</h5>
4122<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4123 <a href="#t_floating">floating point</a> type to a larger
4124 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4125 used to make a <i>no-op cast</i> because it always changes bits. Use
4126 <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]4127
4128<h5>Example:</h5>
4129<pre>
4130 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4131 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4132</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134</div>
4135
4136<!-- _______________________________________________________________________ -->
4137<div class="doc_subsubsection">
4138 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4139</div>
4140<div class="doc_text">
4141
4142<h5>Syntax:</h5>
4143<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4144 &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]4145</pre>
4146
4147<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4148<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4149 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4150
4151<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4152<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4153 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4154 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4155 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4156 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4157
4158<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4159<p>The '<tt>fptoui</tt>' instruction converts its
4160 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4161 towards zero) unsigned integer value. If the value cannot fit
4162 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4163
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4164<h5>Example:</h5>
4165<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4166 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4167 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4168 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4170
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4171</div>
4172
4173<!-- _______________________________________________________________________ -->
4174<div class="doc_subsubsection">
4175 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4176</div>
4177<div class="doc_text">
4178
4179<h5>Syntax:</h5>
4180<pre>
4181 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4182</pre>
4183
4184<h5>Overview:</h5>
4185<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4186 <a href="#t_floating">floating point</a> <tt>value</tt> to
4187 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4190<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4191 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4192 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4193 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4194 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4195
4196<h5>Semantics:</h5>
4197<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4198 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4199 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4200 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4202<h5>Example:</h5>
4203<pre>
4204 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4205 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4206 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4207</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4209</div>
4210
4211<!-- _______________________________________________________________________ -->
4212<div class="doc_subsubsection">
4213 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4214</div>
4215<div class="doc_text">
4216
4217<h5>Syntax:</h5>
4218<pre>
4219 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4220</pre>
4221
4222<h5>Overview:</h5>
4223<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4224 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4227<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]4228 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4229 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4230 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4231 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4232
4233<h5>Semantics:</h5>
4234<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4235 integer quantity and converts it to the corresponding floating point
4236 value. If the value cannot fit in the floating point value, the results are
4237 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4239<h5>Example:</h5>
4240<pre>
4241 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4242 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245</div>
4246
4247<!-- _______________________________________________________________________ -->
4248<div class="doc_subsubsection">
4249 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4250</div>
4251<div class="doc_text">
4252
4253<h5>Syntax:</h5>
4254<pre>
4255 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4256</pre>
4257
4258<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4259<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4260 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4261
4262<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4263<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]4264 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4265 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4266 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4267 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268
4269<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4270<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4271 quantity and converts it to the corresponding floating point value. If the
4272 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4273
4274<h5>Example:</h5>
4275<pre>
4276 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4277 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4278</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4280</div>
4281
4282<!-- _______________________________________________________________________ -->
4283<div class="doc_subsubsection">
4284 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4285</div>
4286<div class="doc_text">
4287
4288<h5>Syntax:</h5>
4289<pre>
4290 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4291</pre>
4292
4293<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4294<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4295 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4296
4297<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4298<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4299 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4300 <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]4301
4302<h5>Semantics:</h5>
4303<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4304 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4305 truncating or zero extending that value to the size of the integer type. If
4306 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4307 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4308 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4309 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4310
4311<h5>Example:</h5>
4312<pre>
4313 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4314 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4315</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4317</div>
4318
4319<!-- _______________________________________________________________________ -->
4320<div class="doc_subsubsection">
4321 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4322</div>
4323<div class="doc_text">
4324
4325<h5>Syntax:</h5>
4326<pre>
4327 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4328</pre>
4329
4330<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4332 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333
4334<h5>Arguments:</h5>
4335<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4336 value to cast, and a type to cast it to, which must be a
4337 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4338
4339<h5>Semantics:</h5>
4340<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4341 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4342 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4343 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4344 than the size of a pointer then a zero extension is done. If they are the
4345 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4346
4347<h5>Example:</h5>
4348<pre>
4349 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4350 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4351 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4352</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4353
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354</div>
4355
4356<!-- _______________________________________________________________________ -->
4357<div class="doc_subsubsection">
4358 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4359</div>
4360<div class="doc_text">
4361
4362<h5>Syntax:</h5>
4363<pre>
4364 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4365</pre>
4366
4367<h5>Overview:</h5>
4368<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4369 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370
4371<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4372<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4373 non-aggregate first class value, and a type to cast it to, which must also be
4374 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4375 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4376 identical. If the source type is a pointer, the destination type must also be
4377 a pointer. This instruction supports bitwise conversion of vectors to
4378 integers and to vectors of other types (as long as they have the same
4379 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4380
4381<h5>Semantics:</h5>
4382<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4383 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4384 this conversion. The conversion is done as if the <tt>value</tt> had been
4385 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4386 be converted to other pointer types with this instruction. To convert
4387 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4388 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4389
4390<h5>Example:</h5>
4391<pre>
4392 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4393 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4394 %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]4395</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4397</div>
4398
4399<!-- ======================================================================= -->
4400<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4402<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4403
4404<p>The instructions in this category are the "miscellaneous" instructions, which
4405 defy better classification.</p>
4406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407</div>
4408
4409<!-- _______________________________________________________________________ -->
4410<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4411</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4415<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4416<pre>
4417 &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]4418</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4420<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4421<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4422 boolean values based on comparison of its two integer, integer vector, or
4423 pointer operands.</p>
4424
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4425<h5>Arguments:</h5>
4426<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4427 the condition code indicating the kind of comparison to perform. It is not a
4428 value, just a keyword. The possible condition code are:</p>
4429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430<ol>
4431 <li><tt>eq</tt>: equal</li>
4432 <li><tt>ne</tt>: not equal </li>
4433 <li><tt>ugt</tt>: unsigned greater than</li>
4434 <li><tt>uge</tt>: unsigned greater or equal</li>
4435 <li><tt>ult</tt>: unsigned less than</li>
4436 <li><tt>ule</tt>: unsigned less or equal</li>
4437 <li><tt>sgt</tt>: signed greater than</li>
4438 <li><tt>sge</tt>: signed greater or equal</li>
4439 <li><tt>slt</tt>: signed less than</li>
4440 <li><tt>sle</tt>: signed less or equal</li>
4441</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4444 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4445 typed. They must also be identical types.</p>
4446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4448<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4449 condition code given as <tt>cond</tt>. The comparison performed always yields
4450 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4451 result, as follows:</p>
4452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4453<ol>
4454 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4455 <tt>false</tt> otherwise. No sign interpretation is necessary or
4456 performed.</li>
4457
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4458 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4459 <tt>false</tt> otherwise. No sign interpretation is necessary or
4460 performed.</li>
4461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4463 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4464
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4465 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4466 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4467 to <tt>op2</tt>.</li>
4468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4470 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4471
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4472 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4473 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4474
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4475 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4476 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4478 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4479 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4480 to <tt>op2</tt>.</li>
4481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4483 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4485 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4486 <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]4487</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4489<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4490 values are compared as if they were integers.</p>
4491
4492<p>If the operands are integer vectors, then they are compared element by
4493 element. The result is an <tt>i1</tt> vector with the same number of elements
4494 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4495
4496<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4497<pre>
4498 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4499 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4500 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4501 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4502 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4503 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4504</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4505
4506<p>Note that the code generator does not yet support vector types with
4507 the <tt>icmp</tt> instruction.</p>
4508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4509</div>
4510
4511<!-- _______________________________________________________________________ -->
4512<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4513</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4515<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4517<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4518<pre>
4519 &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]4520</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4523<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4524 values based on comparison of its operands.</p>
4525
4526<p>If the operands are floating point scalars, then the result type is a boolean
4527(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4528
4529<p>If the operands are floating point vectors, then the result type is a vector
4530 of boolean with the same number of elements as the operands being
4531 compared.</p>
4532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4533<h5>Arguments:</h5>
4534<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4535 the condition code indicating the kind of comparison to perform. It is not a
4536 value, just a keyword. The possible condition code are:</p>
4537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4538<ol>
4539 <li><tt>false</tt>: no comparison, always returns false</li>
4540 <li><tt>oeq</tt>: ordered and equal</li>
4541 <li><tt>ogt</tt>: ordered and greater than </li>
4542 <li><tt>oge</tt>: ordered and greater than or equal</li>
4543 <li><tt>olt</tt>: ordered and less than </li>
4544 <li><tt>ole</tt>: ordered and less than or equal</li>
4545 <li><tt>one</tt>: ordered and not equal</li>
4546 <li><tt>ord</tt>: ordered (no nans)</li>
4547 <li><tt>ueq</tt>: unordered or equal</li>
4548 <li><tt>ugt</tt>: unordered or greater than </li>
4549 <li><tt>uge</tt>: unordered or greater than or equal</li>
4550 <li><tt>ult</tt>: unordered or less than </li>
4551 <li><tt>ule</tt>: unordered or less than or equal</li>
4552 <li><tt>une</tt>: unordered or not equal</li>
4553 <li><tt>uno</tt>: unordered (either nans)</li>
4554 <li><tt>true</tt>: no comparison, always returns true</li>
4555</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4557<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4558 <i>unordered</i> means that either operand may be a QNAN.</p>
4559
4560<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4561 a <a href="#t_floating">floating point</a> type or
4562 a <a href="#t_vector">vector</a> of floating point type. They must have
4563 identical types.</p>
4564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4565<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4566<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4567 according to the condition code given as <tt>cond</tt>. If the operands are
4568 vectors, then the vectors are compared element by element. Each comparison
4569 performed always yields an <a href="#t_primitive">i1</a> result, as
4570 follows:</p>
4571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4572<ol>
4573 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4575 <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]4576 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4578 <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]4579 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4581 <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]4582 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584 <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]4585 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587 <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]4588 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590 <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]4591 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4592
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4593 <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]4594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4595 <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]4596 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4598 <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]4599 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4601 <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]4602 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4604 <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]4605 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4607 <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]4608 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610 <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]4611 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4613 <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]4614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4615 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4616</ol>
4617
4618<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4619<pre>
4620 &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]4621 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4622 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4623 &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]4624</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4625
4626<p>Note that the code generator does not yet support vector types with
4627 the <tt>fcmp</tt> instruction.</p>
4628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4629</div>
4630
4631<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4632<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4633 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4634</div>
4635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4636<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4638<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4639<pre>
4640 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4641</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4643<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4644<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4645 SSA graph representing the function.</p>
4646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4647<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4648<p>The type of the incoming values is specified with the first type field. After
4649 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4650 one pair for each predecessor basic block of the current block. Only values
4651 of <a href="#t_firstclass">first class</a> type may be used as the value
4652 arguments to the PHI node. Only labels may be used as the label
4653 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4654
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655<p>There must be no non-phi instructions between the start of a basic block and
4656 the PHI instructions: i.e. PHI instructions must be first in a basic
4657 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4658
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4660 occur on the edge from the corresponding predecessor block to the current
4661 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4662 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4664<h5>Semantics:</h5>
4665<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4666 specified by the pair corresponding to the predecessor basic block that
4667 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4670<pre>
4671Loop: ; Infinite loop that counts from 0 on up...
4672 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4673 %nextindvar = add i32 %indvar, 1
4674 br label %Loop
4675</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4677</div>
4678
4679<!-- _______________________________________________________________________ -->
4680<div class="doc_subsubsection">
4681 <a name="i_select">'<tt>select</tt>' Instruction</a>
4682</div>
4683
4684<div class="doc_text">
4685
4686<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4687<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4688 &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>
4689
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4690 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691</pre>
4692
4693<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4694<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4695 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4696
4697
4698<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4699<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4700 values indicating the condition, and two values of the
4701 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4702 vectors and the condition is a scalar, then entire vectors are selected, not
4703 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4704
4705<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4706<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4707 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4708
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4709<p>If the condition is a vector of i1, then the value arguments must be vectors
4710 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4711
4712<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4713<pre>
4714 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4715</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4716
4717<p>Note that the code generator does not yet support conditions
4718 with vector type.</p>
4719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720</div>
4721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4722<!-- _______________________________________________________________________ -->
4723<div class="doc_subsubsection">
4724 <a name="i_call">'<tt>call</tt>' Instruction</a>
4725</div>
4726
4727<div class="doc_text">
4728
4729<h5>Syntax:</h5>
4730<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4731 &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]4732</pre>
4733
4734<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4735<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4736
4737<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738<p>This instruction requires several arguments:</p>
4739
4740<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4741 <li>The optional "tail" marker indicates whether the callee function accesses
4742 any allocas or varargs in the caller. If the "tail" marker is present,
4743 the function call is eligible for tail call optimization. Note that calls
4744 may be marked "tail" even if they do not occur before
4745 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4746
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4747 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4748 convention</a> the call should use. If none is specified, the call
4749 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4750
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4751 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4752 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4753 '<tt>inreg</tt>' attributes are valid here.</li>
4754
4755 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4756 type of the return value. Functions that return no value are marked
4757 <tt><a href="#t_void">void</a></tt>.</li>
4758
4759 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4760 being invoked. The argument types must match the types implied by this
4761 signature. This type can be omitted if the function is not varargs and if
4762 the function type does not return a pointer to a function.</li>
4763
4764 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4765 be invoked. In most cases, this is a direct function invocation, but
4766 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4767 to function value.</li>
4768
4769 <li>'<tt>function args</tt>': argument list whose types match the function
4770 signature argument types. All arguments must be of
4771 <a href="#t_firstclass">first class</a> type. If the function signature
4772 indicates the function accepts a variable number of arguments, the extra
4773 arguments can be specified.</li>
4774
4775 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4776 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4777 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4778</ol>
4779
4780<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4781<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4782 a specified function, with its incoming arguments bound to the specified
4783 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4784 function, control flow continues with the instruction after the function
4785 call, and the return value of the function is bound to the result
4786 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4787
4788<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4789<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4790 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4791 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4792 %X = tail call i32 @foo() <i>; yields i32</i>
4793 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4794 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4795
4796 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4797 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4798 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4799 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4800 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4801 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802</pre>
4803
4804</div>
4805
4806<!-- _______________________________________________________________________ -->
4807<div class="doc_subsubsection">
4808 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4809</div>
4810
4811<div class="doc_text">
4812
4813<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4814<pre>
4815 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4816</pre>
4817
4818<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4819<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4820 the "variable argument" area of a function call. It is used to implement the
4821 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4822
4823<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4824<p>This instruction takes a <tt>va_list*</tt> value and the type of the
4825 argument. It returns a value of the specified argument type and increments
4826 the <tt>va_list</tt> to point to the next argument. The actual type
4827 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4828
4829<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4830<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
4831 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
4832 to the next argument. For more information, see the variable argument
4833 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4834
4835<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]4836 take a variable number of arguments, for example, the <tt>vfprintf</tt>
4837 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4839<p><tt>va_arg</tt> is an LLVM instruction instead of
4840 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
4841 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842
4843<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4845
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4846<p>Note that the code generator does not yet fully support va_arg on many
4847 targets. Also, it does not currently support va_arg with aggregate types on
4848 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850</div>
4851
4852<!-- *********************************************************************** -->
4853<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4854<!-- *********************************************************************** -->
4855
4856<div class="doc_text">
4857
4858<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4859 well known names and semantics and are required to follow certain
4860 restrictions. Overall, these intrinsics represent an extension mechanism for
4861 the LLVM language that does not require changing all of the transformations
4862 in LLVM when adding to the language (or the bitcode reader/writer, the
4863 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4864
4865<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4866 prefix is reserved in LLVM for intrinsic names; thus, function names may not
4867 begin with this prefix. Intrinsic functions must always be external
4868 functions: you cannot define the body of intrinsic functions. Intrinsic
4869 functions may only be used in call or invoke instructions: it is illegal to
4870 take the address of an intrinsic function. Additionally, because intrinsic
4871 functions are part of the LLVM language, it is required if any are added that
4872 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4873
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4874<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
4875 family of functions that perform the same operation but on different data
4876 types. Because LLVM can represent over 8 million different integer types,
4877 overloading is used commonly to allow an intrinsic function to operate on any
4878 integer type. One or more of the argument types or the result type can be
4879 overloaded to accept any integer type. Argument types may also be defined as
4880 exactly matching a previous argument's type or the result type. This allows
4881 an intrinsic function which accepts multiple arguments, but needs all of them
4882 to be of the same type, to only be overloaded with respect to a single
4883 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4885<p>Overloaded intrinsics will have the names of its overloaded argument types
4886 encoded into its function name, each preceded by a period. Only those types
4887 which are overloaded result in a name suffix. Arguments whose type is matched
4888 against another type do not. For example, the <tt>llvm.ctpop</tt> function
4889 can take an integer of any width and returns an integer of exactly the same
4890 integer width. This leads to a family of functions such as
4891 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
4892 %val)</tt>. Only one type, the return type, is overloaded, and only one type
4893 suffix is required. Because the argument's type is matched against the return
4894 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4895
4896<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4897 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4898
4899</div>
4900
4901<!-- ======================================================================= -->
4902<div class="doc_subsection">
4903 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4904</div>
4905
4906<div class="doc_text">
4907
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4908<p>Variable argument support is defined in LLVM with
4909 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4910 intrinsic functions. These functions are related to the similarly named
4911 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4912
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4913<p>All of these functions operate on arguments that use a target-specific value
4914 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
4915 not define what this type is, so all transformations should be prepared to
4916 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4917
4918<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]4919 instruction and the variable argument handling intrinsic functions are
4920 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921
4922<div class="doc_code">
4923<pre>
4924define i32 @test(i32 %X, ...) {
4925 ; Initialize variable argument processing
4926 %ap = alloca i8*
4927 %ap2 = bitcast i8** %ap to i8*
4928 call void @llvm.va_start(i8* %ap2)
4929
4930 ; Read a single integer argument
4931 %tmp = va_arg i8** %ap, i32
4932
4933 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4934 %aq = alloca i8*
4935 %aq2 = bitcast i8** %aq to i8*
4936 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4937 call void @llvm.va_end(i8* %aq2)
4938
4939 ; Stop processing of arguments.
4940 call void @llvm.va_end(i8* %ap2)
4941 ret i32 %tmp
4942}
4943
4944declare void @llvm.va_start(i8*)
4945declare void @llvm.va_copy(i8*, i8*)
4946declare void @llvm.va_end(i8*)
4947</pre>
4948</div>
4949
4950</div>
4951
4952<!-- _______________________________________________________________________ -->
4953<div class="doc_subsubsection">
4954 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4955</div>
4956
4957
4958<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4960<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4961<pre>
4962 declare void %llvm.va_start(i8* &lt;arglist&gt;)
4963</pre>
4964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4965<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4966<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
4967 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]4968
4969<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4970<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]4971
4972<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4973<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]4974 macro available in C. In a target-dependent way, it initializes
4975 the <tt>va_list</tt> element to which the argument points, so that the next
4976 call to <tt>va_arg</tt> will produce the first variable argument passed to
4977 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
4978 need to know the last argument of the function as the compiler can figure
4979 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4980
4981</div>
4982
4983<!-- _______________________________________________________________________ -->
4984<div class="doc_subsubsection">
4985 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4986</div>
4987
4988<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4989
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4990<h5>Syntax:</h5>
4991<pre>
4992 declare void @llvm.va_end(i8* &lt;arglist&gt;)
4993</pre>
4994
4995<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4996<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4997 which has been initialized previously
4998 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4999 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5000
5001<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5002<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5003
5004<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5005<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]5006 macro available in C. In a target-dependent way, it destroys
5007 the <tt>va_list</tt> element to which the argument points. Calls
5008 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5009 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5010 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011
5012</div>
5013
5014<!-- _______________________________________________________________________ -->
5015<div class="doc_subsubsection">
5016 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5017</div>
5018
5019<div class="doc_text">
5020
5021<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5022<pre>
5023 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5024</pre>
5025
5026<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5027<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5028 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5029
5030<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5031<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]5032 The second argument is a pointer to a <tt>va_list</tt> element to copy
5033 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5034
5035<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5036<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]5037 macro available in C. In a target-dependent way, it copies the
5038 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5039 element. This intrinsic is necessary because
5040 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5041 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5042
5043</div>
5044
5045<!-- ======================================================================= -->
5046<div class="doc_subsection">
5047 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5048</div>
5049
5050<div class="doc_text">
5051
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5052<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5053Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5054intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5055roots on the stack</a>, as well as garbage collector implementations that
5056require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5057barriers. Front-ends for type-safe garbage collected languages should generate
5058these intrinsics to make use of the LLVM garbage collectors. For more details,
5059see <a href="GarbageCollection.html">Accurate Garbage Collection with
5060LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5061
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5062<p>The garbage collection intrinsics only operate on objects in the generic
5063 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5064
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5065</div>
5066
5067<!-- _______________________________________________________________________ -->
5068<div class="doc_subsubsection">
5069 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5070</div>
5071
5072<div class="doc_text">
5073
5074<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5075<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5076 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5077</pre>
5078
5079<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5080<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]5081 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082
5083<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5084<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5085 root pointer. The second pointer (which must be either a constant or a
5086 global value address) contains the meta-data to be associated with the
5087 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088
5089<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5090<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]5091 location. At compile-time, the code generator generates information to allow
5092 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5093 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5094 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5095
5096</div>
5097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5098<!-- _______________________________________________________________________ -->
5099<div class="doc_subsubsection">
5100 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5101</div>
5102
5103<div class="doc_text">
5104
5105<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5106<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5107 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5108</pre>
5109
5110<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5111<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5112 locations, allowing garbage collector implementations that require read
5113 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5114
5115<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5116<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]5117 allocated from the garbage collector. The first object is a pointer to the
5118 start of the referenced object, if needed by the language runtime (otherwise
5119 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5120
5121<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5122<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5123 instruction, but may be replaced with substantially more complex code by the
5124 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5125 may only be used in a function which <a href="#gc">specifies a GC
5126 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5127
5128</div>
5129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5130<!-- _______________________________________________________________________ -->
5131<div class="doc_subsubsection">
5132 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5133</div>
5134
5135<div class="doc_text">
5136
5137<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5138<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5139 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5140</pre>
5141
5142<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5143<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5144 locations, allowing garbage collector implementations that require write
5145 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5146
5147<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5148<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]5149 object to store it to, and the third is the address of the field of Obj to
5150 store to. If the runtime does not require a pointer to the object, Obj may
5151 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5152
5153<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5154<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5155 instruction, but may be replaced with substantially more complex code by the
5156 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5157 may only be used in a function which <a href="#gc">specifies a GC
5158 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5159
5160</div>
5161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5162<!-- ======================================================================= -->
5163<div class="doc_subsection">
5164 <a name="int_codegen">Code Generator Intrinsics</a>
5165</div>
5166
5167<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5168
5169<p>These intrinsics are provided by LLVM to expose special features that may
5170 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5171
5172</div>
5173
5174<!-- _______________________________________________________________________ -->
5175<div class="doc_subsubsection">
5176 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5177</div>
5178
5179<div class="doc_text">
5180
5181<h5>Syntax:</h5>
5182<pre>
5183 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5184</pre>
5185
5186<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5187<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5188 target-specific value indicating the return address of the current function
5189 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190
5191<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5192<p>The argument to this intrinsic indicates which function to return the address
5193 for. Zero indicates the calling function, one indicates its caller, etc.
5194 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5195
5196<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5197<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5198 indicating the return address of the specified call frame, or zero if it
5199 cannot be identified. The value returned by this intrinsic is likely to be
5200 incorrect or 0 for arguments other than zero, so it should only be used for
5201 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5203<p>Note that calling this intrinsic does not prevent function inlining or other
5204 aggressive transformations, so the value returned may not be that of the
5205 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5206
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5207</div>
5208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5209<!-- _______________________________________________________________________ -->
5210<div class="doc_subsubsection">
5211 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5212</div>
5213
5214<div class="doc_text">
5215
5216<h5>Syntax:</h5>
5217<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5218 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5219</pre>
5220
5221<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5222<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5223 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224
5225<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5226<p>The argument to this intrinsic indicates which function to return the frame
5227 pointer for. Zero indicates the calling function, one indicates its caller,
5228 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5229
5230<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5231<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5232 indicating the frame address of the specified call frame, or zero if it
5233 cannot be identified. The value returned by this intrinsic is likely to be
5234 incorrect or 0 for arguments other than zero, so it should only be used for
5235 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5236
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5237<p>Note that calling this intrinsic does not prevent function inlining or other
5238 aggressive transformations, so the value returned may not be that of the
5239 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5241</div>
5242
5243<!-- _______________________________________________________________________ -->
5244<div class="doc_subsubsection">
5245 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5246</div>
5247
5248<div class="doc_text">
5249
5250<h5>Syntax:</h5>
5251<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5252 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5253</pre>
5254
5255<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5256<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5257 of the function stack, for use
5258 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5259 useful for implementing language features like scoped automatic variable
5260 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5261
5262<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5263<p>This intrinsic returns a opaque pointer value that can be passed
5264 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5265 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5266 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5267 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5268 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5269 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5270
5271</div>
5272
5273<!-- _______________________________________________________________________ -->
5274<div class="doc_subsubsection">
5275 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5276</div>
5277
5278<div class="doc_text">
5279
5280<h5>Syntax:</h5>
5281<pre>
5282 declare void @llvm.stackrestore(i8 * %ptr)
5283</pre>
5284
5285<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5286<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5287 the function stack to the state it was in when the
5288 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5289 executed. This is useful for implementing language features like scoped
5290 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5291
5292<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5293<p>See the description
5294 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5295
5296</div>
5297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5298<!-- _______________________________________________________________________ -->
5299<div class="doc_subsubsection">
5300 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5301</div>
5302
5303<div class="doc_text">
5304
5305<h5>Syntax:</h5>
5306<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5307 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]5308</pre>
5309
5310<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5311<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5312 insert a prefetch instruction if supported; otherwise, it is a noop.
5313 Prefetches have no effect on the behavior of the program but can change its
5314 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5315
5316<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5317<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5318 specifier determining if the fetch should be for a read (0) or write (1),
5319 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5320 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5321 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5322
5323<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5324<p>This intrinsic does not modify the behavior of the program. In particular,
5325 prefetches cannot trap and do not produce a value. On targets that support
5326 this intrinsic, the prefetch can provide hints to the processor cache for
5327 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328
5329</div>
5330
5331<!-- _______________________________________________________________________ -->
5332<div class="doc_subsubsection">
5333 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5334</div>
5335
5336<div class="doc_text">
5337
5338<h5>Syntax:</h5>
5339<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5340 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5341</pre>
5342
5343<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5344<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5345 Counter (PC) in a region of code to simulators and other tools. The method
5346 is target specific, but it is expected that the marker will use exported
5347 symbols to transmit the PC of the marker. The marker makes no guarantees
5348 that it will remain with any specific instruction after optimizations. It is
5349 possible that the presence of a marker will inhibit optimizations. The
5350 intended use is to be inserted after optimizations to allow correlations of
5351 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352
5353<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5354<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5355
5356<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5357<p>This intrinsic does not modify the behavior of the program. Backends that do
5358 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5359
5360</div>
5361
5362<!-- _______________________________________________________________________ -->
5363<div class="doc_subsubsection">
5364 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5365</div>
5366
5367<div class="doc_text">
5368
5369<h5>Syntax:</h5>
5370<pre>
5371 declare i64 @llvm.readcyclecounter( )
5372</pre>
5373
5374<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5375<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5376 counter register (or similar low latency, high accuracy clocks) on those
5377 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5378 should map to RPCC. As the backing counters overflow quickly (on the order
5379 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5380
5381<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5382<p>When directly supported, reading the cycle counter should not modify any
5383 memory. Implementations are allowed to either return a application specific
5384 value or a system wide value. On backends without support, this is lowered
5385 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5386
5387</div>
5388
5389<!-- ======================================================================= -->
5390<div class="doc_subsection">
5391 <a name="int_libc">Standard C Library Intrinsics</a>
5392</div>
5393
5394<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5395
5396<p>LLVM provides intrinsics for a few important standard C library functions.
5397 These intrinsics allow source-language front-ends to pass information about
5398 the alignment of the pointer arguments to the code generator, providing
5399 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400
5401</div>
5402
5403<!-- _______________________________________________________________________ -->
5404<div class="doc_subsubsection">
5405 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5406</div>
5407
5408<div class="doc_text">
5409
5410<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5411<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5412 integer bit width. Not all targets support all bit widths however.</p>
5413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5414<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5415 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5416 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5417 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5418 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5419 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5420 i32 &lt;len&gt;, i32 &lt;align&gt;)
5421 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5422 i64 &lt;len&gt;, i32 &lt;align&gt;)
5423</pre>
5424
5425<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5426<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5427 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5428
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5429<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5430 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5431
5432<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5433<p>The first argument is a pointer to the destination, the second is a pointer
5434 to the source. The third argument is an integer argument specifying the
5435 number of bytes to copy, and the fourth argument is the alignment of the
5436 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5437
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5438<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5439 then the caller guarantees that both the source and destination pointers are
5440 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441
5442<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5443<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5444 source location to the destination location, which are not allowed to
5445 overlap. It copies "len" bytes of memory over. If the argument is known to
5446 be aligned to some boundary, this can be specified as the fourth argument,
5447 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449</div>
5450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5451<!-- _______________________________________________________________________ -->
5452<div class="doc_subsubsection">
5453 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5454</div>
5455
5456<div class="doc_text">
5457
5458<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5459<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]5460 width. Not all targets support all bit widths however.</p>
5461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5462<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5463 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5464 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5465 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5466 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5468 i32 &lt;len&gt;, i32 &lt;align&gt;)
5469 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5470 i64 &lt;len&gt;, i32 &lt;align&gt;)
5471</pre>
5472
5473<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5474<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5475 source location to the destination location. It is similar to the
5476 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5477 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5478
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5479<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5480 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5481
5482<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5483<p>The first argument is a pointer to the destination, the second is a pointer
5484 to the source. The third argument is an integer argument specifying the
5485 number of bytes to copy, and the fourth argument is the alignment of the
5486 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5488<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5489 then the caller guarantees that the source and destination pointers are
5490 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5491
5492<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5493<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5494 source location to the destination location, which may overlap. It copies
5495 "len" bytes of memory over. If the argument is known to be aligned to some
5496 boundary, this can be specified as the fourth argument, otherwise it should
5497 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5499</div>
5500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5501<!-- _______________________________________________________________________ -->
5502<div class="doc_subsubsection">
5503 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5504</div>
5505
5506<div class="doc_text">
5507
5508<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5509<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]5510 width. Not all targets support all bit widths however.</p>
5511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5512<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5513 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5514 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5515 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5516 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5517 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5518 i32 &lt;len&gt;, i32 &lt;align&gt;)
5519 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5520 i64 &lt;len&gt;, i32 &lt;align&gt;)
5521</pre>
5522
5523<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5524<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5525 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5526
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5527<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5528 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5529
5530<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5531<p>The first argument is a pointer to the destination to fill, the second is the
5532 byte value to fill it with, the third argument is an integer argument
5533 specifying the number of bytes to fill, and the fourth argument is the known
5534 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5535
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5536<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5537 then the caller guarantees that the destination pointer is aligned to that
5538 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5539
5540<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5541<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5542 at the destination location. If the argument is known to be aligned to some
5543 boundary, this can be specified as the fourth argument, otherwise it should
5544 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5545
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5546</div>
5547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5548<!-- _______________________________________________________________________ -->
5549<div class="doc_subsubsection">
5550 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5551</div>
5552
5553<div class="doc_text">
5554
5555<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5556<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5557 floating point or vector of floating point type. Not all targets support all
5558 types however.</p>
5559
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5560<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5561 declare float @llvm.sqrt.f32(float %Val)
5562 declare double @llvm.sqrt.f64(double %Val)
5563 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5564 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5565 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566</pre>
5567
5568<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5569<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5570 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5571 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5572 behavior for negative numbers other than -0.0 (which allows for better
5573 optimization, because there is no need to worry about errno being
5574 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]5575
5576<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5577<p>The argument and return value are floating point numbers of the same
5578 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579
5580<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5581<p>This function returns the sqrt of the specified operand if it is a
5582 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5584</div>
5585
5586<!-- _______________________________________________________________________ -->
5587<div class="doc_subsubsection">
5588 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5589</div>
5590
5591<div class="doc_text">
5592
5593<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5594<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5595 floating point or vector of floating point type. Not all targets support all
5596 types however.</p>
5597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5599 declare float @llvm.powi.f32(float %Val, i32 %power)
5600 declare double @llvm.powi.f64(double %Val, i32 %power)
5601 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5602 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5603 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5604</pre>
5605
5606<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5607<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5608 specified (positive or negative) power. The order of evaluation of
5609 multiplications is not defined. When a vector of floating point type is
5610 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5611
5612<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5613<p>The second argument is an integer power, and the first is a value to raise to
5614 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5615
5616<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5617<p>This function returns the first value raised to the second power with an
5618 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5619
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5620</div>
5621
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5622<!-- _______________________________________________________________________ -->
5623<div class="doc_subsubsection">
5624 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5625</div>
5626
5627<div class="doc_text">
5628
5629<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5630<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5631 floating point or vector of floating point type. Not all targets support all
5632 types however.</p>
5633
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5634<pre>
5635 declare float @llvm.sin.f32(float %Val)
5636 declare double @llvm.sin.f64(double %Val)
5637 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5638 declare fp128 @llvm.sin.f128(fp128 %Val)
5639 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5640</pre>
5641
5642<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5643<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5644
5645<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5646<p>The argument and return value are floating point numbers of the same
5647 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5648
5649<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5650<p>This function returns the sine of the specified operand, returning the same
5651 values as the libm <tt>sin</tt> functions would, and handles error conditions
5652 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5653
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5654</div>
5655
5656<!-- _______________________________________________________________________ -->
5657<div class="doc_subsubsection">
5658 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5659</div>
5660
5661<div class="doc_text">
5662
5663<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5664<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5665 floating point or vector of floating point type. Not all targets support all
5666 types however.</p>
5667
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5668<pre>
5669 declare float @llvm.cos.f32(float %Val)
5670 declare double @llvm.cos.f64(double %Val)
5671 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5672 declare fp128 @llvm.cos.f128(fp128 %Val)
5673 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5674</pre>
5675
5676<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5677<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5678
5679<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5680<p>The argument and return value are floating point numbers of the same
5681 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5682
5683<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5684<p>This function returns the cosine of the specified operand, returning the same
5685 values as the libm <tt>cos</tt> functions would, and handles error conditions
5686 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5687
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5688</div>
5689
5690<!-- _______________________________________________________________________ -->
5691<div class="doc_subsubsection">
5692 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5693</div>
5694
5695<div class="doc_text">
5696
5697<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5698<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5699 floating point or vector of floating point type. Not all targets support all
5700 types however.</p>
5701
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5702<pre>
5703 declare float @llvm.pow.f32(float %Val, float %Power)
5704 declare double @llvm.pow.f64(double %Val, double %Power)
5705 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5706 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5707 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5708</pre>
5709
5710<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5711<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5712 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5713
5714<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5715<p>The second argument is a floating point power, and the first is a value to
5716 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5717
5718<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5719<p>This function returns the first value raised to the second power, returning
5720 the same values as the libm <tt>pow</tt> functions would, and handles error
5721 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5722
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5723</div>
5724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725<!-- ======================================================================= -->
5726<div class="doc_subsection">
5727 <a name="int_manip">Bit Manipulation Intrinsics</a>
5728</div>
5729
5730<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5731
5732<p>LLVM provides intrinsics for a few important bit manipulation operations.
5733 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5734
5735</div>
5736
5737<!-- _______________________________________________________________________ -->
5738<div class="doc_subsubsection">
5739 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5740</div>
5741
5742<div class="doc_text">
5743
5744<h5>Syntax:</h5>
5745<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5746 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5748<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5749 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5750 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5751 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752</pre>
5753
5754<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5755<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5756 values with an even number of bytes (positive multiple of 16 bits). These
5757 are useful for performing operations on data that is not in the target's
5758 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5759
5760<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5761<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5762 and low byte of the input i16 swapped. Similarly,
5763 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5764 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5765 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5766 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5767 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5768 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5769
5770</div>
5771
5772<!-- _______________________________________________________________________ -->
5773<div class="doc_subsubsection">
5774 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5775</div>
5776
5777<div class="doc_text">
5778
5779<h5>Syntax:</h5>
5780<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]5781 width. Not all targets support all bit widths however.</p>
5782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5784 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5785 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5787 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5788 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789</pre>
5790
5791<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5792<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5793 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5794
5795<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5796<p>The only argument is the value to be counted. The argument may be of any
5797 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798
5799<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5800<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]5801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5802</div>
5803
5804<!-- _______________________________________________________________________ -->
5805<div class="doc_subsubsection">
5806 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5807</div>
5808
5809<div class="doc_text">
5810
5811<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5812<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5813 integer bit width. Not all targets support all bit widths however.</p>
5814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5815<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5816 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5817 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5818 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5819 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5820 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5821</pre>
5822
5823<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5824<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5825 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5826
5827<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5828<p>The only argument is the value to be counted. The argument may be of any
5829 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5830
5831<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5832<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
5833 zeros in a variable. If the src == 0 then the result is the size in bits of
5834 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836</div>
5837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5838<!-- _______________________________________________________________________ -->
5839<div class="doc_subsubsection">
5840 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5841</div>
5842
5843<div class="doc_text">
5844
5845<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5846<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5847 integer bit width. Not all targets support all bit widths however.</p>
5848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5849<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5850 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5851 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5852 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5853 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5854 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855</pre>
5856
5857<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5858<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5859 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5860
5861<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5862<p>The only argument is the value to be counted. The argument may be of any
5863 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5864
5865<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5866<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
5867 zeros in a variable. If the src == 0 then the result is the size in bits of
5868 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5870</div>
5871
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5872<!-- ======================================================================= -->
5873<div class="doc_subsection">
5874 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5875</div>
5876
5877<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5878
5879<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5880
5881</div>
5882
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5883<!-- _______________________________________________________________________ -->
5884<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5885 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5886</div>
5887
5888<div class="doc_text">
5889
5890<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5891<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]5892 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5893
5894<pre>
5895 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5896 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5897 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5898</pre>
5899
5900<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5901<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5902 a signed addition of the two arguments, and indicate whether an overflow
5903 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5904
5905<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5906<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]5907 be of integer types of any bit width, but they must have the same bit
5908 width. The second element of the result structure must be of
5909 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5910 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5911
5912<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5913<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5914 a signed addition of the two variables. They return a structure &mdash; the
5915 first element of which is the signed summation, and the second element of
5916 which is a bit specifying if the signed summation resulted in an
5917 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5918
5919<h5>Examples:</h5>
5920<pre>
5921 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5922 %sum = extractvalue {i32, i1} %res, 0
5923 %obit = extractvalue {i32, i1} %res, 1
5924 br i1 %obit, label %overflow, label %normal
5925</pre>
5926
5927</div>
5928
5929<!-- _______________________________________________________________________ -->
5930<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5931 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5932</div>
5933
5934<div class="doc_text">
5935
5936<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5937<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]5938 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5939
5940<pre>
5941 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
5942 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5943 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
5944</pre>
5945
5946<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5947<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5948 an unsigned addition of the two arguments, and indicate whether a carry
5949 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5950
5951<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5952<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]5953 be of integer types of any bit width, but they must have the same bit
5954 width. The second element of the result structure must be of
5955 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5956 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5957
5958<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5959<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5960 an unsigned addition of the two arguments. They return a structure &mdash;
5961 the first element of which is the sum, and the second element of which is a
5962 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5963
5964<h5>Examples:</h5>
5965<pre>
5966 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5967 %sum = extractvalue {i32, i1} %res, 0
5968 %obit = extractvalue {i32, i1} %res, 1
5969 br i1 %obit, label %carry, label %normal
5970</pre>
5971
5972</div>
5973
5974<!-- _______________________________________________________________________ -->
5975<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5976 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5977</div>
5978
5979<div class="doc_text">
5980
5981<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5982<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]5983 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5984
5985<pre>
5986 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
5987 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
5988 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
5989</pre>
5990
5991<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5992<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5993 a signed subtraction of the two arguments, and indicate whether an overflow
5994 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5995
5996<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5997<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]5998 be of integer types of any bit width, but they must have the same bit
5999 width. The second element of the result structure must be of
6000 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6001 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6002
6003<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6004<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6005 a signed subtraction of the two arguments. They return a structure &mdash;
6006 the first element of which is the subtraction, and the second element of
6007 which is a bit specifying if the signed subtraction resulted in an
6008 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6009
6010<h5>Examples:</h5>
6011<pre>
6012 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6013 %sum = extractvalue {i32, i1} %res, 0
6014 %obit = extractvalue {i32, i1} %res, 1
6015 br i1 %obit, label %overflow, label %normal
6016</pre>
6017
6018</div>
6019
6020<!-- _______________________________________________________________________ -->
6021<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6022 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6023</div>
6024
6025<div class="doc_text">
6026
6027<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6028<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]6029 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6030
6031<pre>
6032 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6033 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6034 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6035</pre>
6036
6037<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6038<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6039 an unsigned subtraction of the two arguments, and indicate whether an
6040 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6041
6042<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6043<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]6044 be of integer types of any bit width, but they must have the same bit
6045 width. The second element of the result structure must be of
6046 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6047 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6048
6049<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6050<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6051 an unsigned subtraction of the two arguments. They return a structure &mdash;
6052 the first element of which is the subtraction, and the second element of
6053 which is a bit specifying if the unsigned subtraction resulted in an
6054 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6055
6056<h5>Examples:</h5>
6057<pre>
6058 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6059 %sum = extractvalue {i32, i1} %res, 0
6060 %obit = extractvalue {i32, i1} %res, 1
6061 br i1 %obit, label %overflow, label %normal
6062</pre>
6063
6064</div>
6065
6066<!-- _______________________________________________________________________ -->
6067<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6068 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6069</div>
6070
6071<div class="doc_text">
6072
6073<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6074<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]6075 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6076
6077<pre>
6078 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6079 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6080 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6081</pre>
6082
6083<h5>Overview:</h5>
6084
6085<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6086 a signed multiplication of the two arguments, and indicate whether an
6087 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6088
6089<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6090<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]6091 be of integer types of any bit width, but they must have the same bit
6092 width. The second element of the result structure must be of
6093 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6094 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6095
6096<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6097<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6098 a signed multiplication of the two arguments. They return a structure &mdash;
6099 the first element of which is the multiplication, and the second element of
6100 which is a bit specifying if the signed multiplication resulted in an
6101 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6102
6103<h5>Examples:</h5>
6104<pre>
6105 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6106 %sum = extractvalue {i32, i1} %res, 0
6107 %obit = extractvalue {i32, i1} %res, 1
6108 br i1 %obit, label %overflow, label %normal
6109</pre>
6110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6111</div>
6112
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6113<!-- _______________________________________________________________________ -->
6114<div class="doc_subsubsection">
6115 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6116</div>
6117
6118<div class="doc_text">
6119
6120<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6121<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]6122 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6123
6124<pre>
6125 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6126 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6127 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6128</pre>
6129
6130<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6131<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6132 a unsigned multiplication of the two arguments, and indicate whether an
6133 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6134
6135<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6136<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]6137 be of integer types of any bit width, but they must have the same bit
6138 width. The second element of the result structure must be of
6139 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6140 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6141
6142<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6143<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6144 an unsigned multiplication of the two arguments. They return a structure
6145 &mdash; the first element of which is the multiplication, and the second
6146 element of which is a bit specifying if the unsigned multiplication resulted
6147 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6148
6149<h5>Examples:</h5>
6150<pre>
6151 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6152 %sum = extractvalue {i32, i1} %res, 0
6153 %obit = extractvalue {i32, i1} %res, 1
6154 br i1 %obit, label %overflow, label %normal
6155</pre>
6156
6157</div>
6158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6159<!-- ======================================================================= -->
6160<div class="doc_subsection">
6161 <a name="int_debugger">Debugger Intrinsics</a>
6162</div>
6163
6164<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6165
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6166<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6167 prefix), are described in
6168 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6169 Level Debugging</a> document.</p>
6170
6171</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6172
6173<!-- ======================================================================= -->
6174<div class="doc_subsection">
6175 <a name="int_eh">Exception Handling Intrinsics</a>
6176</div>
6177
6178<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6179
6180<p>The LLVM exception handling intrinsics (which all start with
6181 <tt>llvm.eh.</tt> prefix), are described in
6182 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6183 Handling</a> document.</p>
6184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6185</div>
6186
6187<!-- ======================================================================= -->
6188<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6189 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6190</div>
6191
6192<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6193
6194<p>This intrinsic makes it possible to excise one parameter, marked with
6195 the <tt>nest</tt> attribute, from a function. The result is a callable
6196 function pointer lacking the nest parameter - the caller does not need to
6197 provide a value for it. Instead, the value to use is stored in advance in a
6198 "trampoline", a block of memory usually allocated on the stack, which also
6199 contains code to splice the nest value into the argument list. This is used
6200 to implement the GCC nested function address extension.</p>
6201
6202<p>For example, if the function is
6203 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6204 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6205 follows:</p>
6206
6207<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6208<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6209 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6210 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6211 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6212 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6213</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6214</div>
6215
6216<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6217 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6218
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6219</div>
6220
6221<!-- _______________________________________________________________________ -->
6222<div class="doc_subsubsection">
6223 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6224</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6225
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6226<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6227
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6228<h5>Syntax:</h5>
6229<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6230 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]6231</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6232
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6233<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6234<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6235 function pointer suitable for executing it.</p>
6236
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6237<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6238<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6239 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6240 sufficiently aligned block of memory; this memory is written to by the
6241 intrinsic. Note that the size and the alignment are target-specific - LLVM
6242 currently provides no portable way of determining them, so a front-end that
6243 generates this intrinsic needs to have some target-specific knowledge.
6244 The <tt>func</tt> argument must hold a function bitcast to
6245 an <tt>i8*</tt>.</p>
6246
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6247<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6248<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6249 dependent code, turning it into a function. A pointer to this function is
6250 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6251 function pointer type</a> before being called. The new function's signature
6252 is the same as that of <tt>func</tt> with any arguments marked with
6253 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6254 is allowed, and it must be of pointer type. Calling the new function is
6255 equivalent to calling <tt>func</tt> with the same argument list, but
6256 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6257 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6258 by <tt>tramp</tt> is modified, then the effect of any later call to the
6259 returned function pointer is undefined.</p>
6260
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6261</div>
6262
6263<!-- ======================================================================= -->
6264<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6265 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6266</div>
6267
6268<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6269
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6270<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6271 hardware constructs for atomic operations and memory synchronization. This
6272 provides an interface to the hardware, not an interface to the programmer. It
6273 is aimed at a low enough level to allow any programming models or APIs
6274 (Application Programming Interfaces) which need atomic behaviors to map
6275 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6276 hardware provides a "universal IR" for source languages, it also provides a
6277 starting point for developing a "universal" atomic operation and
6278 synchronization IR.</p>
6279
6280<p>These do <em>not</em> form an API such as high-level threading libraries,
6281 software transaction memory systems, atomic primitives, and intrinsic
6282 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6283 application libraries. The hardware interface provided by LLVM should allow
6284 a clean implementation of all of these APIs and parallel programming models.
6285 No one model or paradigm should be selected above others unless the hardware
6286 itself ubiquitously does so.</p>
6287
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6288</div>
6289
6290<!-- _______________________________________________________________________ -->
6291<div class="doc_subsubsection">
6292 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6293</div>
6294<div class="doc_text">
6295<h5>Syntax:</h5>
6296<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6297 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]6298</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6299
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6300<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6301<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6302 specific pairs of memory access types.</p>
6303
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6304<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6305<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6306 The first four arguments enables a specific barrier as listed below. The
6307 fith argument specifies that the barrier applies to io or device or uncached
6308 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6309
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6310<ul>
6311 <li><tt>ll</tt>: load-load barrier</li>
6312 <li><tt>ls</tt>: load-store barrier</li>
6313 <li><tt>sl</tt>: store-load barrier</li>
6314 <li><tt>ss</tt>: store-store barrier</li>
6315 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6316</ul>
6317
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6318<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6319<p>This intrinsic causes the system to enforce some ordering constraints upon
6320 the loads and stores of the program. This barrier does not
6321 indicate <em>when</em> any events will occur, it only enforces
6322 an <em>order</em> in which they occur. For any of the specified pairs of load
6323 and store operations (f.ex. load-load, or store-load), all of the first
6324 operations preceding the barrier will complete before any of the second
6325 operations succeeding the barrier begin. Specifically the semantics for each
6326 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6327
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6328<ul>
6329 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6330 after the barrier begins.</li>
6331 <li><tt>ls</tt>: All loads before the barrier must complete before any
6332 store after the barrier begins.</li>
6333 <li><tt>ss</tt>: All stores before the barrier must complete before any
6334 store after the barrier begins.</li>
6335 <li><tt>sl</tt>: All stores before the barrier must complete before any
6336 load after the barrier begins.</li>
6337</ul>
6338
6339<p>These semantics are applied with a logical "and" behavior when more than one
6340 is enabled in a single memory barrier intrinsic.</p>
6341
6342<p>Backends may implement stronger barriers than those requested when they do
6343 not support as fine grained a barrier as requested. Some architectures do
6344 not need all types of barriers and on such architectures, these become
6345 noops.</p>
6346
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6347<h5>Example:</h5>
6348<pre>
6349%ptr = malloc i32
6350 store i32 4, %ptr
6351
6352%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6353 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6354 <i>; guarantee the above finishes</i>
6355 store i32 8, %ptr <i>; before this begins</i>
6356</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6357
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6358</div>
6359
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6360<!-- _______________________________________________________________________ -->
6361<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6362 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6363</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6364
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6365<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6366
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6367<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6368<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6369 any integer bit width and for different address spaces. Not all targets
6370 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6371
6372<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6373 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6374 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6375 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6376 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]6377</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6378
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6379<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6380<p>This loads a value in memory and compares it to a given value. If they are
6381 equal, it stores a new value into the memory.</p>
6382
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6383<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6384<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6385 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6386 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6387 this integer type. While any bit width integer may be used, targets may only
6388 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6389
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6390<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6391<p>This entire intrinsic must be executed atomically. It first loads the value
6392 in memory pointed to by <tt>ptr</tt> and compares it with the
6393 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6394 memory. The loaded value is yielded in all cases. This provides the
6395 equivalent of an atomic compare-and-swap operation within the SSA
6396 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6397
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6398<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6399<pre>
6400%ptr = malloc i32
6401 store i32 4, %ptr
6402
6403%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6404%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6405 <i>; yields {i32}:result1 = 4</i>
6406%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6407%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6408
6409%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6410%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6411 <i>; yields {i32}:result2 = 8</i>
6412%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6413
6414%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6415</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6416
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6417</div>
6418
6419<!-- _______________________________________________________________________ -->
6420<div class="doc_subsubsection">
6421 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6422</div>
6423<div class="doc_text">
6424<h5>Syntax:</h5>
6425
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6426<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6427 integer bit width. Not all targets support all bit widths however.</p>
6428
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6429<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6430 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6431 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6432 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6433 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]6434</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6435
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6436<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6437<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6438 the value from memory. It then stores the value in <tt>val</tt> in the memory
6439 at <tt>ptr</tt>.</p>
6440
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6441<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6442<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6443 the <tt>val</tt> argument and the result must be integers of the same bit
6444 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6445 integer type. The targets may only lower integer representations they
6446 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6447
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6448<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6449<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6450 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6451 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6452
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6453<h5>Examples:</h5>
6454<pre>
6455%ptr = malloc i32
6456 store i32 4, %ptr
6457
6458%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6459%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6460 <i>; yields {i32}:result1 = 4</i>
6461%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6462%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6463
6464%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6465%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6466 <i>; yields {i32}:result2 = 8</i>
6467
6468%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6469%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6470</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6472</div>
6473
6474<!-- _______________________________________________________________________ -->
6475<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6476 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6477
6478</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6479
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6480<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6481
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6482<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6483<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6484 any integer bit width. Not all targets support all bit widths however.</p>
6485
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6486<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6487 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6488 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6489 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6490 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]6491</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6492
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6493<h5>Overview:</h5>
6494<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6495 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6496
6497<h5>Arguments:</h5>
6498<p>The intrinsic takes two arguments, the first a pointer to an integer value
6499 and the second an integer value. The result is also an integer value. These
6500 integer types can have any bit width, but they must all have the same bit
6501 width. The targets may only lower integer representations they support.</p>
6502
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6503<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6504<p>This intrinsic does a series of operations atomically. It first loads the
6505 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6506 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]6507
6508<h5>Examples:</h5>
6509<pre>
6510%ptr = malloc i32
6511 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6512%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6513 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6514%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6515 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6516%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6517 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6518%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6519</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6520
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6521</div>
6522
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6523<!-- _______________________________________________________________________ -->
6524<div class="doc_subsubsection">
6525 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6526
6527</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6528
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6529<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6530
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6531<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6532<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6533 any integer bit width and for different address spaces. Not all targets
6534 support all bit widths however.</p>
6535
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6536<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6537 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6538 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6539 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6540 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]6541</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6542
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6543<h5>Overview:</h5>
6544<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6545 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6546
6547<h5>Arguments:</h5>
6548<p>The intrinsic takes two arguments, the first a pointer to an integer value
6549 and the second an integer value. The result is also an integer value. These
6550 integer types can have any bit width, but they must all have the same bit
6551 width. The targets may only lower integer representations they support.</p>
6552
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6553<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6554<p>This intrinsic does a series of operations atomically. It first loads the
6555 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6556 result to <tt>ptr</tt>. It yields the original value stored
6557 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6558
6559<h5>Examples:</h5>
6560<pre>
6561%ptr = malloc i32
6562 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6563%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6564 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6565%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6566 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6567%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6568 <i>; yields {i32}:result3 = 2</i>
6569%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6570</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6571
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6572</div>
6573
6574<!-- _______________________________________________________________________ -->
6575<div class="doc_subsubsection">
6576 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6577 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6578 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6579 <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]6580</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6581
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6582<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6583
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6584<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6585<p>These are overloaded intrinsics. You can
6586 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6587 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6588 bit width and for different address spaces. Not all targets support all bit
6589 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6590
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6591<pre>
6592 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6593 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6594 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6595 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]6596</pre>
6597
6598<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6599 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6600 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6601 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6602 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]6603</pre>
6604
6605<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6606 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6607 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6608 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6609 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]6610</pre>
6611
6612<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6613 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6614 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6615 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6616 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]6617</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6618
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6619<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6620<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6621 the value stored in memory at <tt>ptr</tt>. It yields the original value
6622 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6623
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6624<h5>Arguments:</h5>
6625<p>These intrinsics take two arguments, the first a pointer to an integer value
6626 and the second an integer value. The result is also an integer value. These
6627 integer types can have any bit width, but they must all have the same bit
6628 width. The targets may only lower integer representations they support.</p>
6629
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6630<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6631<p>These intrinsics does a series of operations atomically. They first load the
6632 value stored at <tt>ptr</tt>. They then do the bitwise
6633 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6634 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6635
6636<h5>Examples:</h5>
6637<pre>
6638%ptr = malloc i32
6639 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6640%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6641 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6642%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6643 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6644%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6645 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6646%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6647 <i>; yields {i32}:result3 = FF</i>
6648%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6649</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6650
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6651</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6652
6653<!-- _______________________________________________________________________ -->
6654<div class="doc_subsubsection">
6655 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6656 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6657 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6658 <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]6659</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6660
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6661<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6662
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6663<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6664<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6665 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6666 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6667 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6668
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6669<pre>
6670 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6671 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6672 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6673 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]6674</pre>
6675
6676<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6677 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6678 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6679 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6680 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]6681</pre>
6682
6683<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6684 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6685 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6686 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6687 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]6688</pre>
6689
6690<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6691 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6692 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6693 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6694 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]6695</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6696
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6697<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6698<p>These intrinsics takes the signed or unsigned minimum or maximum of
6699 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6700 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6701
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6702<h5>Arguments:</h5>
6703<p>These intrinsics take two arguments, the first a pointer to an integer value
6704 and the second an integer value. The result is also an integer value. These
6705 integer types can have any bit width, but they must all have the same bit
6706 width. The targets may only lower integer representations they support.</p>
6707
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6708<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6709<p>These intrinsics does a series of operations atomically. They first load the
6710 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6711 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6712 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6713
6714<h5>Examples:</h5>
6715<pre>
6716%ptr = malloc i32
6717 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6718%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6719 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6720%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6721 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6722%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6723 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6724%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6725 <i>; yields {i32}:result3 = 8</i>
6726%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6727</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6728
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6729</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6730
6731<!-- ======================================================================= -->
6732<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6733 <a name="int_general">General Intrinsics</a>
6734</div>
6735
6736<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6737
6738<p>This class of intrinsics is designed to be generic and has no specific
6739 purpose.</p>
6740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6741</div>
6742
6743<!-- _______________________________________________________________________ -->
6744<div class="doc_subsubsection">
6745 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6746</div>
6747
6748<div class="doc_text">
6749
6750<h5>Syntax:</h5>
6751<pre>
6752 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6753</pre>
6754
6755<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6756<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6757
6758<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6759<p>The first argument is a pointer to a value, the second is a pointer to a
6760 global string, the third is a pointer to a global string which is the source
6761 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6762
6763<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6764<p>This intrinsic allows annotation of local variables with arbitrary strings.
6765 This can be useful for special purpose optimizations that want to look for
6766 these annotations. These have no other defined use, they are ignored by code
6767 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6769</div>
6770
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6771<!-- _______________________________________________________________________ -->
6772<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6773 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6774</div>
6775
6776<div class="doc_text">
6777
6778<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6779<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6780 any integer bit width.</p>
6781
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6782<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6783 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6784 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6785 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6786 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6787 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]6788</pre>
6789
6790<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6791<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6792
6793<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6794<p>The first argument is an integer value (result of some expression), the
6795 second is a pointer to a global string, the third is a pointer to a global
6796 string which is the source file name, and the last argument is the line
6797 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6798
6799<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6800<p>This intrinsic allows annotations to be put on arbitrary expressions with
6801 arbitrary strings. This can be useful for special purpose optimizations that
6802 want to look for these annotations. These have no other defined use, they
6803 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6804
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6805</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6806
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6807<!-- _______________________________________________________________________ -->
6808<div class="doc_subsubsection">
6809 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6810</div>
6811
6812<div class="doc_text">
6813
6814<h5>Syntax:</h5>
6815<pre>
6816 declare void @llvm.trap()
6817</pre>
6818
6819<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6820<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6821
6822<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6823<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6824
6825<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6826<p>This intrinsics is lowered to the target dependent trap instruction. If the
6827 target does not have a trap instruction, this intrinsic will be lowered to
6828 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6829
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6830</div>
6831
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6832<!-- _______________________________________________________________________ -->
6833<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6834 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6835</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6836
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6837<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6838
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6839<h5>Syntax:</h5>
6840<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6842</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6843
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6844<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6845<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
6846 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
6847 ensure that it is placed on the stack before local variables.</p>
6848
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6849<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6850<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
6851 arguments. The first argument is the value loaded from the stack
6852 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
6853 that has enough space to hold the value of the guard.</p>
6854
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6855<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6856<p>This intrinsic causes the prologue/epilogue inserter to force the position of
6857 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6858 stack. This is to ensure that if a local variable on the stack is
6859 overwritten, it will destroy the value of the guard. When the function exits,
6860 the guard on the stack is checked against the original guard. If they're
6861 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
6862 function.</p>
6863
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6864</div>
6865
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6866<!-- *********************************************************************** -->
6867<hr>
6868<address>
6869 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6870 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6871 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6872 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]6873
6874 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6875 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6876 Last modified: $Date$
6877</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6879</body>
6880</html>