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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ed5fcb2e925f74af628b9effe85f63edbff27f03 / . / 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.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
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>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2603 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2604 &lt;result&gt; = signed add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2605 &lt;result&gt; = unsigned 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]2606</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608<h5>Overview:</h5>
2609<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2611<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2612<p>The two arguments to the '<tt>add</tt>' instruction must
2613 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2614 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2617<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2618
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2619<p>If the sum has unsigned overflow, the result returned is the mathematical
2620 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]2621
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2622<p>Because LLVM integers use a two's complement representation, this instruction
2623 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2624
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2625<p>If the <tt>signed</tt> and/or <tt>unsigned</tt> keywords are present,
2626 the behavior of the <tt>add</tt> is undefined if signed and/or unsigned
2627 overflow, respectively, occurs.</p>
2628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2630<pre>
2631 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2632</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2636<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2637<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2638 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2639</div>
2640
2641<div class="doc_text">
2642
2643<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2644<pre>
2645 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2646</pre>
2647
2648<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2649<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2650
2651<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2652<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2653 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2654 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2655
2656<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2657<p>The value produced is the floating point sum of the two operands.</p>
2658
2659<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2660<pre>
2661 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2662</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2663
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2664</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2665
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2666<!-- _______________________________________________________________________ -->
2667<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2668 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2669</div>
2670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2673<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2674<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2675 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2676 &lt;result&gt; = signed sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2677 &lt;result&gt; = unsigned 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]2678</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680<h5>Overview:</h5>
2681<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2682 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2683
2684<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2685 '<tt>neg</tt>' instruction present in most other intermediate
2686 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2688<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2689<p>The two arguments to the '<tt>sub</tt>' instruction must
2690 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2691 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2694<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2695
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2696<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2697 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2698 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2699
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2700<p>Because LLVM integers use a two's complement representation, this instruction
2701 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2702
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2703<p>If the <tt>signed</tt> and/or <tt>unsigned</tt> keywords are present,
2704 the behavior of the <tt>sub</tt> is undefined if signed and/or unsigned
2705 overflow, respectively, occurs.</p>
2706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2707<h5>Example:</h5>
2708<pre>
2709 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2710 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2711</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2713</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2715<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2716<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2717 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2718</div>
2719
2720<div class="doc_text">
2721
2722<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2723<pre>
2724 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2725</pre>
2726
2727<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2728<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2729 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2730
2731<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2732 '<tt>fneg</tt>' instruction present in most other intermediate
2733 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2734
2735<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]2736<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2737 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2738 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2739
2740<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2741<p>The value produced is the floating point difference of the two operands.</p>
2742
2743<h5>Example:</h5>
2744<pre>
2745 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2746 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2747</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2748
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2749</div>
2750
2751<!-- _______________________________________________________________________ -->
2752<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2753 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2754</div>
2755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2758<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2759<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2760 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2761 &lt;result&gt; = signed mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2762 &lt;result&gt; = unsigned 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]2763</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2765<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2766<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2769<p>The two arguments to the '<tt>mul</tt>' instruction must
2770 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2771 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2772
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2774<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2775
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2776<p>If the result of the multiplication has unsigned overflow, the result
2777 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
2778 width of the result.</p>
2779
2780<p>Because LLVM integers use a two's complement representation, and the result
2781 is the same width as the operands, this instruction returns the correct
2782 result for both signed and unsigned integers. If a full product
2783 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
2784 be sign-extended or zero-extended as appropriate to the width of the full
2785 product.</p>
2786
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2787<p>If the <tt>signed</tt> and/or <tt>unsigned</tt> keywords are present,
2788 the behavior of the <tt>mul</tt> is undefined if signed and/or unsigned
2789 overflow, respectively, occurs.</p>
2790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2791<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2792<pre>
2793 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2795
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2796</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2799<div class="doc_subsubsection">
2800 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2801</div>
2802
2803<div class="doc_text">
2804
2805<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2806<pre>
2807 &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]2808</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2809
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2810<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2811<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2812
2813<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2814<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2815 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2816 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2817
2818<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2819<p>The value produced is the floating point product of the two operands.</p>
2820
2821<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2822<pre>
2823 &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]2824</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2825
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2826</div>
2827
2828<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2829<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2830</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2831
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2832<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2834<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2835<pre>
2836 &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]2837</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2839<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2840<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2842<h5>Arguments:</h5>
2843<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2844 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2845 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2847<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2848<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2849
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2850<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2851 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2852
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2853<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2856<pre>
2857 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2860</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862<!-- _______________________________________________________________________ -->
2863<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2864</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2865
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2869<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2870 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2871 &lt;result&gt; = exact 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]2872</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2874<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2875<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2877<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2878<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2879 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2880 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2882<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2883<p>The value produced is the signed integer quotient of the two operands rounded
2884 towards zero.</p>
2885
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2886<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2887 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2888
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2889<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2890 undefined behavior; this is a rare case, but can occur, for example, by doing
2891 a 32-bit division of -2147483648 by -1.</p>
2892
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame^]2893<p>If the <tt>exact</tt> keyword is present, the result of the <tt>sdiv</tt>
2894 is undefined if the result would be rounded or if overflow occurs.</p>
2895
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2896<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2897<pre>
2898 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2899</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2901</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903<!-- _______________________________________________________________________ -->
2904<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2905Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2907<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2909<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2910<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2911 &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]2912</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2913
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2914<h5>Overview:</h5>
2915<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917<h5>Arguments:</h5>
2918<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2919 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2920 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2922<h5>Semantics:</h5>
2923<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2926<pre>
2927 &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]2928</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2932<!-- _______________________________________________________________________ -->
2933<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2934</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2936<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2937
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2938<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2939<pre>
2940 &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]2941</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2943<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2944<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
2945 division of its two arguments.</p>
2946
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2948<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2949 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2950 values. Both arguments must have identical types.</p>
2951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2952<h5>Semantics:</h5>
2953<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2954 This instruction always performs an unsigned division to get the
2955 remainder.</p>
2956
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2957<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2958 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2959
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2960<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2962<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2963<pre>
2964 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2965</pre>
2966
2967</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2969<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2970<div class="doc_subsubsection">
2971 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2972</div>
2973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2974<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2975
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2976<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2977<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2978 &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]2979</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2980
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2981<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2982<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
2983 division of its two operands. This instruction can also take
2984 <a href="#t_vector">vector</a> versions of the values in which case the
2985 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2987<h5>Arguments:</h5>
2988<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2989 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2990 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2992<h5>Semantics:</h5>
2993<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2994 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2995 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
2996 a value. For more information about the difference,
2997 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2998 Math Forum</a>. For a table of how this is implemented in various languages,
2999 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3000 Wikipedia: modulo operation</a>.</p>
3001
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3002<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3003 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3004
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3005<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3006 Overflow also leads to undefined behavior; this is a rare case, but can
3007 occur, for example, by taking the remainder of a 32-bit division of
3008 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3009 lets srem be implemented using instructions that return both the result of
3010 the division and the remainder.)</p>
3011
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3012<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3013<pre>
3014 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3015</pre>
3016
3017</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3018
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3019<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3020<div class="doc_subsubsection">
3021 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3022
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3023<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3024
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3025<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3026<pre>
3027 &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]3028</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3031<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3032 its two operands.</p>
3033
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3034<h5>Arguments:</h5>
3035<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3036 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3037 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3039<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3040<p>This instruction returns the <i>remainder</i> of a division. The remainder
3041 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3044<pre>
3045 &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]3046</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3048</div>
3049
3050<!-- ======================================================================= -->
3051<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3052Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3053
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3054<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3055
3056<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3057 program. They are generally very efficient instructions and can commonly be
3058 strength reduced from other instructions. They require two operands of the
3059 same type, execute an operation on them, and produce a single value. The
3060 resulting value is the same type as its operands.</p>
3061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3062</div>
3063
3064<!-- _______________________________________________________________________ -->
3065<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3066Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3067
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3068<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3069
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3070<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3071<pre>
3072 &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]3073</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3074
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3075<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3077 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3078
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3079<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3080<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3081 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3082 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3084<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3085<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3086 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3087 is (statically or dynamically) negative or equal to or larger than the number
3088 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3089 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3090 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3091
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3092<h5>Example:</h5>
3093<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3094 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3095 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3096 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3097 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3098 &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]3099</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3100
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3101</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3103<!-- _______________________________________________________________________ -->
3104<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3105Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3106
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3107<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3109<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3110<pre>
3111 &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]3112</pre>
3113
3114<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3115<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3116 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117
3118<h5>Arguments:</h5>
3119<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3120 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3121 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3122
3123<h5>Semantics:</h5>
3124<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3125 significant bits of the result will be filled with zero bits after the shift.
3126 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3127 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3128 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3129 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3130
3131<h5>Example:</h5>
3132<pre>
3133 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3134 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3135 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3136 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3137 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3138 &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]3139</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3140
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3141</div>
3142
3143<!-- _______________________________________________________________________ -->
3144<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3145Instruction</a> </div>
3146<div class="doc_text">
3147
3148<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3149<pre>
3150 &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]3151</pre>
3152
3153<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3154<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3155 operand shifted to the right a specified number of bits with sign
3156 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157
3158<h5>Arguments:</h5>
3159<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3160 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3161 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162
3163<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164<p>This instruction always performs an arithmetic shift right operation, The
3165 most significant bits of the result will be filled with the sign bit
3166 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3167 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3168 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3169 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3170
3171<h5>Example:</h5>
3172<pre>
3173 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3174 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3175 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3176 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3177 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3178 &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]3179</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3181</div>
3182
3183<!-- _______________________________________________________________________ -->
3184<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3185Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3187<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3190<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3191 &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]3192</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3194<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3195<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3196 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3198<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3199<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3200 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3201 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3203<h5>Semantics:</h5>
3204<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3206<table border="1" cellspacing="0" cellpadding="4">
3207 <tbody>
3208 <tr>
3209 <td>In0</td>
3210 <td>In1</td>
3211 <td>Out</td>
3212 </tr>
3213 <tr>
3214 <td>0</td>
3215 <td>0</td>
3216 <td>0</td>
3217 </tr>
3218 <tr>
3219 <td>0</td>
3220 <td>1</td>
3221 <td>0</td>
3222 </tr>
3223 <tr>
3224 <td>1</td>
3225 <td>0</td>
3226 <td>0</td>
3227 </tr>
3228 <tr>
3229 <td>1</td>
3230 <td>1</td>
3231 <td>1</td>
3232 </tr>
3233 </tbody>
3234</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3236<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3237<pre>
3238 &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]3239 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3240 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3241</pre>
3242</div>
3243<!-- _______________________________________________________________________ -->
3244<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3245
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3246<div class="doc_text">
3247
3248<h5>Syntax:</h5>
3249<pre>
3250 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3251</pre>
3252
3253<h5>Overview:</h5>
3254<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3255 two operands.</p>
3256
3257<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3258<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3259 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3260 values. Both arguments must have identical types.</p>
3261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3262<h5>Semantics:</h5>
3263<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3265<table border="1" cellspacing="0" cellpadding="4">
3266 <tbody>
3267 <tr>
3268 <td>In0</td>
3269 <td>In1</td>
3270 <td>Out</td>
3271 </tr>
3272 <tr>
3273 <td>0</td>
3274 <td>0</td>
3275 <td>0</td>
3276 </tr>
3277 <tr>
3278 <td>0</td>
3279 <td>1</td>
3280 <td>1</td>
3281 </tr>
3282 <tr>
3283 <td>1</td>
3284 <td>0</td>
3285 <td>1</td>
3286 </tr>
3287 <tr>
3288 <td>1</td>
3289 <td>1</td>
3290 <td>1</td>
3291 </tr>
3292 </tbody>
3293</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3295<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3296<pre>
3297 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3298 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3299 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3300</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3302</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3304<!-- _______________________________________________________________________ -->
3305<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3306Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3308<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3309
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3310<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3311<pre>
3312 &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]3313</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3315<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3316<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3317 its two operands. The <tt>xor</tt> is used to implement the "one's
3318 complement" operation, which is the "~" operator in C.</p>
3319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3320<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3321<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3323 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3325<h5>Semantics:</h5>
3326<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3328<table border="1" cellspacing="0" cellpadding="4">
3329 <tbody>
3330 <tr>
3331 <td>In0</td>
3332 <td>In1</td>
3333 <td>Out</td>
3334 </tr>
3335 <tr>
3336 <td>0</td>
3337 <td>0</td>
3338 <td>0</td>
3339 </tr>
3340 <tr>
3341 <td>0</td>
3342 <td>1</td>
3343 <td>1</td>
3344 </tr>
3345 <tr>
3346 <td>1</td>
3347 <td>0</td>
3348 <td>1</td>
3349 </tr>
3350 <tr>
3351 <td>1</td>
3352 <td>1</td>
3353 <td>0</td>
3354 </tr>
3355 </tbody>
3356</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3358<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3359<pre>
3360 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3362 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3363 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3364</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366</div>
3367
3368<!-- ======================================================================= -->
3369<div class="doc_subsection">
3370 <a name="vectorops">Vector Operations</a>
3371</div>
3372
3373<div class="doc_text">
3374
3375<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3376 target-independent manner. These instructions cover the element-access and
3377 vector-specific operations needed to process vectors effectively. While LLVM
3378 does directly support these vector operations, many sophisticated algorithms
3379 will want to use target-specific intrinsics to take full advantage of a
3380 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3381
3382</div>
3383
3384<!-- _______________________________________________________________________ -->
3385<div class="doc_subsubsection">
3386 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3387</div>
3388
3389<div class="doc_text">
3390
3391<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3392<pre>
3393 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3394</pre>
3395
3396<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3397<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3398 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399
3400
3401<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3402<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3403 of <a href="#t_vector">vector</a> type. The second operand is an index
3404 indicating the position from which to extract the element. The index may be
3405 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3406
3407<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3408<p>The result is a scalar of the same type as the element type of
3409 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3410 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3411 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3412
3413<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3414<pre>
3415 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3416</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3417
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3418</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3419
3420<!-- _______________________________________________________________________ -->
3421<div class="doc_subsubsection">
3422 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3423</div>
3424
3425<div class="doc_text">
3426
3427<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3428<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3429 &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]3430</pre>
3431
3432<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3433<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3434 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3435
3436<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3437<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3438 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3439 whose type must equal the element type of the first operand. The third
3440 operand is an index indicating the position at which to insert the value.
3441 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442
3443<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3444<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3445 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3446 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3447 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3448
3449<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450<pre>
3451 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3452</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3453
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3454</div>
3455
3456<!-- _______________________________________________________________________ -->
3457<div class="doc_subsubsection">
3458 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3459</div>
3460
3461<div class="doc_text">
3462
3463<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3464<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3465 &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]3466</pre>
3467
3468<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3470 from two input vectors, returning a vector with the same element type as the
3471 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3472
3473<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3474<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3475 with types that match each other. The third argument is a shuffle mask whose
3476 element type is always 'i32'. The result of the instruction is a vector
3477 whose length is the same as the shuffle mask and whose element type is the
3478 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3479
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3480<p>The shuffle mask operand is required to be a constant vector with either
3481 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482
3483<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3484<p>The elements of the two input vectors are numbered from left to right across
3485 both of the vectors. The shuffle mask operand specifies, for each element of
3486 the result vector, which element of the two input vectors the result element
3487 gets. The element selector may be undef (meaning "don't care") and the
3488 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3489
3490<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3491<pre>
3492 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3493 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3494 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3495 &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]3496 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3497 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3498 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3499 &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]3500</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3501
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3502</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3503
3504<!-- ======================================================================= -->
3505<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3506 <a name="aggregateops">Aggregate Operations</a>
3507</div>
3508
3509<div class="doc_text">
3510
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3511<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3512
3513</div>
3514
3515<!-- _______________________________________________________________________ -->
3516<div class="doc_subsubsection">
3517 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3518</div>
3519
3520<div class="doc_text">
3521
3522<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3523<pre>
3524 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3525</pre>
3526
3527<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3528<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3529 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3530
3531<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3532<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3533 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3534 operands are constant indices to specify which value to extract in a similar
3535 manner as indices in a
3536 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3537
3538<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3539<p>The result is the value at the position in the aggregate specified by the
3540 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3541
3542<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3543<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3544 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3545</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3546
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3547</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3548
3549<!-- _______________________________________________________________________ -->
3550<div class="doc_subsubsection">
3551 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3552</div>
3553
3554<div class="doc_text">
3555
3556<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3557<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3558 &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]3559</pre>
3560
3561<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3562<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3563 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3564
3565
3566<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3568 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3569 second operand is a first-class value to insert. The following operands are
3570 constant indices indicating the position at which to insert the value in a
3571 similar manner as indices in a
3572 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3573 value to insert must have the same type as the value identified by the
3574 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3575
3576<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3577<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3578 that of <tt>val</tt> except that the value at the position specified by the
3579 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3580
3581<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3582<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3583 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3584</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3585
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3586</div>
3587
3588
3589<!-- ======================================================================= -->
3590<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3591 <a name="memoryops">Memory Access and Addressing Operations</a>
3592</div>
3593
3594<div class="doc_text">
3595
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3596<p>A key design point of an SSA-based representation is how it represents
3597 memory. In LLVM, no memory locations are in SSA form, which makes things
3598 very simple. This section describes how to read, write, allocate, and free
3599 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3600
3601</div>
3602
3603<!-- _______________________________________________________________________ -->
3604<div class="doc_subsubsection">
3605 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3606</div>
3607
3608<div class="doc_text">
3609
3610<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3611<pre>
3612 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3613</pre>
3614
3615<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3616<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
3617 returns a pointer to it. The object is always allocated in the generic
3618 address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3619
3620<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3621<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3622 <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory from the operating
3623 system and returns a pointer of the appropriate type to the program. If
3624 "NumElements" is specified, it is the number of elements allocated, otherwise
3625 "NumElements" is defaulted to be one. If a constant alignment is specified,
3626 the value result of the allocation is guaranteed to be aligned to at least
3627 that boundary. If not specified, or if zero, the target can choose to align
3628 the allocation on any convenient boundary compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3629
3630<p>'<tt>type</tt>' must be a sized type.</p>
3631
3632<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3633<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
3634 pointer is returned. The result of a zero byte allocation is undefined. The
3635 result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3636
3637<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3638<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3639 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640
3641 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3642 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3643 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3644 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3645 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3646</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3647
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3648<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3650</div>
3651
3652<!-- _______________________________________________________________________ -->
3653<div class="doc_subsubsection">
3654 <a name="i_free">'<tt>free</tt>' Instruction</a>
3655</div>
3656
3657<div class="doc_text">
3658
3659<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3660<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3661 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3662</pre>
3663
3664<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3665<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
3666 to be reallocated in the future.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3667
3668<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3669<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
3670 allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3671
3672<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3673<p>Access to the memory pointed to by the pointer is no longer defined after
3674 this instruction executes. If the pointer is null, the operation is a
3675 noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3676
3677<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3678<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3679 %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]3680 free [4 x i8]* %array
3681</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3683</div>
3684
3685<!-- _______________________________________________________________________ -->
3686<div class="doc_subsubsection">
3687 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3688</div>
3689
3690<div class="doc_text">
3691
3692<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3693<pre>
3694 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3695</pre>
3696
3697<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3698<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3699 currently executing function, to be automatically released when this function
3700 returns to its caller. The object is always allocated in the generic address
3701 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702
3703<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3704<p>The '<tt>alloca</tt>' instruction
3705 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3706 runtime stack, returning a pointer of the appropriate type to the program.
3707 If "NumElements" is specified, it is the number of elements allocated,
3708 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3709 specified, the value result of the allocation is guaranteed to be aligned to
3710 at least that boundary. If not specified, or if zero, the target can choose
3711 to align the allocation on any convenient boundary compatible with the
3712 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3713
3714<p>'<tt>type</tt>' may be any sized type.</p>
3715
3716<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3717<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3718 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3719 memory is automatically released when the function returns. The
3720 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3721 variables that must have an address available. When the function returns
3722 (either with the <tt><a href="#i_ret">ret</a></tt>
3723 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3724 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3725
3726<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3727<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3728 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3729 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3730 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3731 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3732</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3734</div>
3735
3736<!-- _______________________________________________________________________ -->
3737<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3738Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3740<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3742<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3743<pre>
3744 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3745 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3746</pre>
3747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3748<h5>Overview:</h5>
3749<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3751<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3752<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3753 from which to load. The pointer must point to
3754 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3755 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3756 number or order of execution of this <tt>load</tt> with other
3757 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3758 instructions. </p>
3759
3760<p>The optional constant "align" argument specifies the alignment of the
3761 operation (that is, the alignment of the memory address). A value of 0 or an
3762 omitted "align" argument means that the operation has the preferential
3763 alignment for the target. It is the responsibility of the code emitter to
3764 ensure that the alignment information is correct. Overestimating the
3765 alignment results in an undefined behavior. Underestimating the alignment may
3766 produce less efficient code. An alignment of 1 is always safe.</p>
3767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3769<p>The location of memory pointed to is loaded. If the value being loaded is of
3770 scalar type then the number of bytes read does not exceed the minimum number
3771 of bytes needed to hold all bits of the type. For example, loading an
3772 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3773 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3774 is undefined if the value was not originally written using a store of the
3775 same type.</p>
3776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3777<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3778<pre>
3779 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3780 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3781 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3782</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3784</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3786<!-- _______________________________________________________________________ -->
3787<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3788Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3790<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3792<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3793<pre>
3794 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]3795 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3796</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3798<h5>Overview:</h5>
3799<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3801<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3802<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
3803 and an address at which to store it. The type of the
3804 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
3805 the <a href="#t_firstclass">first class</a> type of the
3806 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
3807 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
3808 or order of execution of this <tt>store</tt> with other
3809 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3810 instructions.</p>
3811
3812<p>The optional constant "align" argument specifies the alignment of the
3813 operation (that is, the alignment of the memory address). A value of 0 or an
3814 omitted "align" argument means that the operation has the preferential
3815 alignment for the target. It is the responsibility of the code emitter to
3816 ensure that the alignment information is correct. Overestimating the
3817 alignment results in an undefined behavior. Underestimating the alignment may
3818 produce less efficient code. An alignment of 1 is always safe.</p>
3819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3820<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3821<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
3822 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
3823 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
3824 does not exceed the minimum number of bytes needed to hold all bits of the
3825 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
3826 writing a value of a type like <tt>i20</tt> with a size that is not an
3827 integral number of bytes, it is unspecified what happens to the extra bits
3828 that do not belong to the type, but they will typically be overwritten.</p>
3829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3830<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3831<pre>
3832 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3833 store i32 3, i32* %ptr <i>; yields {void}</i>
3834 %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]3835</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3837</div>
3838
3839<!-- _______________________________________________________________________ -->
3840<div class="doc_subsubsection">
3841 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3842</div>
3843
3844<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3846<h5>Syntax:</h5>
3847<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3848 &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]3849</pre>
3850
3851<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3852<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
3853 subelement of an aggregate data structure. It performs address calculation
3854 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3855
3856<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3857<p>The first argument is always a pointer, and forms the basis of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3858 calculation. The remaining arguments are indices, that indicate which of the
3859 elements of the aggregate object are indexed. The interpretation of each
3860 index is dependent on the type being indexed into. The first index always
3861 indexes the pointer value given as the first argument, the second index
3862 indexes a value of the type pointed to (not necessarily the value directly
3863 pointed to, since the first index can be non-zero), etc. The first type
3864 indexed into must be a pointer value, subsequent types can be arrays, vectors
3865 and structs. Note that subsequent types being indexed into can never be
3866 pointers, since that would require loading the pointer before continuing
3867 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3868
3869<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]3870 When indexing into a (packed) structure, only <tt>i32</tt> integer
3871 <b>constants</b> are allowed. When indexing into an array, pointer or
3872 vector, integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3873
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3874<p>For example, let's consider a C code fragment and how it gets compiled to
3875 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3876
3877<div class="doc_code">
3878<pre>
3879struct RT {
3880 char A;
3881 int B[10][20];
3882 char C;
3883};
3884struct ST {
3885 int X;
3886 double Y;
3887 struct RT Z;
3888};
3889
3890int *foo(struct ST *s) {
3891 return &amp;s[1].Z.B[5][13];
3892}
3893</pre>
3894</div>
3895
3896<p>The LLVM code generated by the GCC frontend is:</p>
3897
3898<div class="doc_code">
3899<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3900%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3901%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3902
3903define i32* %foo(%ST* %s) {
3904entry:
3905 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3906 ret i32* %reg
3907}
3908</pre>
3909</div>
3910
3911<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912<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]3913 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3914 }</tt>' type, a structure. The second index indexes into the third element
3915 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3916 i8 }</tt>' type, another structure. The third index indexes into the second
3917 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3918 array. The two dimensions of the array are subscripted into, yielding an
3919 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
3920 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3921
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3922<p>Note that it is perfectly legal to index partially through a structure,
3923 returning a pointer to an inner element. Because of this, the LLVM code for
3924 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3925
3926<pre>
3927 define i32* %foo(%ST* %s) {
3928 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3929 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3930 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3931 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3932 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3933 ret i32* %t5
3934 }
3935</pre>
3936
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3937<p>The getelementptr instruction is often confusing. For some more insight into
3938 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3939
3940<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3941<pre>
3942 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3943 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3944 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3945 %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]3946 <i>; yields i8*:eptr</i>
3947 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3948 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3949 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3950</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3951
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952</div>
3953
3954<!-- ======================================================================= -->
3955<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3956</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3957
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3958<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3959
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3960<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3961 which all take a single operand and a type. They perform various bit
3962 conversions on the operand.</p>
3963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3964</div>
3965
3966<!-- _______________________________________________________________________ -->
3967<div class="doc_subsubsection">
3968 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3969</div>
3970<div class="doc_text">
3971
3972<h5>Syntax:</h5>
3973<pre>
3974 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3975</pre>
3976
3977<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3978<p>The '<tt>trunc</tt>' instruction truncates its operand to the
3979 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3980
3981<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3982<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3983 be an <a href="#t_integer">integer</a> type, and a type that specifies the
3984 size and type of the result, which must be
3985 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
3986 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
3987 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3988
3989<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3990<p>The '<tt>trunc</tt>' instruction truncates the high order bits
3991 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
3992 source size must be larger than the destination size, <tt>trunc</tt> cannot
3993 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3994
3995<h5>Example:</h5>
3996<pre>
3997 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3998 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3999 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
4000</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4002</div>
4003
4004<!-- _______________________________________________________________________ -->
4005<div class="doc_subsubsection">
4006 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4007</div>
4008<div class="doc_text">
4009
4010<h5>Syntax:</h5>
4011<pre>
4012 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4013</pre>
4014
4015<h5>Overview:</h5>
4016<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4017 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4018
4019
4020<h5>Arguments:</h5>
4021<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]4022 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4023 also be of <a href="#t_integer">integer</a> type. The bit size of the
4024 <tt>value</tt> must be smaller than the bit size of the destination type,
4025 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4026
4027<h5>Semantics:</h5>
4028<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]4029 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030
4031<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4032
4033<h5>Example:</h5>
4034<pre>
4035 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4036 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4037</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039</div>
4040
4041<!-- _______________________________________________________________________ -->
4042<div class="doc_subsubsection">
4043 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4044</div>
4045<div class="doc_text">
4046
4047<h5>Syntax:</h5>
4048<pre>
4049 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4050</pre>
4051
4052<h5>Overview:</h5>
4053<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4054
4055<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4056<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4057 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4058 also be of <a href="#t_integer">integer</a> type. The bit size of the
4059 <tt>value</tt> must be smaller than the bit size of the destination type,
4060 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061
4062<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4063<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4064 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4065 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066
4067<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4068
4069<h5>Example:</h5>
4070<pre>
4071 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4072 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4073</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4074
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4075</div>
4076
4077<!-- _______________________________________________________________________ -->
4078<div class="doc_subsubsection">
4079 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4080</div>
4081
4082<div class="doc_text">
4083
4084<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085<pre>
4086 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4087</pre>
4088
4089<h5>Overview:</h5>
4090<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4091 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4092
4093<h5>Arguments:</h5>
4094<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4095 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4096 to cast it to. The size of <tt>value</tt> must be larger than the size of
4097 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4098 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4099
4100<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4101<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4102 <a href="#t_floating">floating point</a> type to a smaller
4103 <a href="#t_floating">floating point</a> type. If the value cannot fit
4104 within the destination type, <tt>ty2</tt>, then the results are
4105 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4106
4107<h5>Example:</h5>
4108<pre>
4109 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4110 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4111</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4113</div>
4114
4115<!-- _______________________________________________________________________ -->
4116<div class="doc_subsubsection">
4117 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4118</div>
4119<div class="doc_text">
4120
4121<h5>Syntax:</h5>
4122<pre>
4123 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4124</pre>
4125
4126<h5>Overview:</h5>
4127<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]4128 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4129
4130<h5>Arguments:</h5>
4131<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4132 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4133 a <a href="#t_floating">floating point</a> type to cast it to. The source
4134 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4135
4136<h5>Semantics:</h5>
4137<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4138 <a href="#t_floating">floating point</a> type to a larger
4139 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4140 used to make a <i>no-op cast</i> because it always changes bits. Use
4141 <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]4142
4143<h5>Example:</h5>
4144<pre>
4145 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4146 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4147</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4148
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4149</div>
4150
4151<!-- _______________________________________________________________________ -->
4152<div class="doc_subsubsection">
4153 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4154</div>
4155<div class="doc_text">
4156
4157<h5>Syntax:</h5>
4158<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4159 &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]4160</pre>
4161
4162<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4163<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4164 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4165
4166<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4167<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4168 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4169 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4170 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4171 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4172
4173<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4174<p>The '<tt>fptoui</tt>' instruction converts its
4175 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4176 towards zero) unsigned integer value. If the value cannot fit
4177 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4179<h5>Example:</h5>
4180<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4181 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4182 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4183 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4184</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4186</div>
4187
4188<!-- _______________________________________________________________________ -->
4189<div class="doc_subsubsection">
4190 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4191</div>
4192<div class="doc_text">
4193
4194<h5>Syntax:</h5>
4195<pre>
4196 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4197</pre>
4198
4199<h5>Overview:</h5>
4200<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4201 <a href="#t_floating">floating point</a> <tt>value</tt> to
4202 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4204<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4205<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4206 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4207 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4208 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4209 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210
4211<h5>Semantics:</h5>
4212<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4213 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4214 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4215 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217<h5>Example:</h5>
4218<pre>
4219 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4220 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4222</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4224</div>
4225
4226<!-- _______________________________________________________________________ -->
4227<div class="doc_subsubsection">
4228 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4229</div>
4230<div class="doc_text">
4231
4232<h5>Syntax:</h5>
4233<pre>
4234 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4235</pre>
4236
4237<h5>Overview:</h5>
4238<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4239 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4241<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4242<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]4243 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4244 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4245 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4246 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247
4248<h5>Semantics:</h5>
4249<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4250 integer quantity and converts it to the corresponding floating point
4251 value. If the value cannot fit in the floating point value, the results are
4252 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4254<h5>Example:</h5>
4255<pre>
4256 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4257 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4259
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260</div>
4261
4262<!-- _______________________________________________________________________ -->
4263<div class="doc_subsubsection">
4264 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4265</div>
4266<div class="doc_text">
4267
4268<h5>Syntax:</h5>
4269<pre>
4270 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4271</pre>
4272
4273<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4274<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4275 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4276
4277<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4278<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]4279 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4280 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4281 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4282 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4283
4284<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4285<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4286 quantity and converts it to the corresponding floating point value. If the
4287 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288
4289<h5>Example:</h5>
4290<pre>
4291 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4292 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4293</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4295</div>
4296
4297<!-- _______________________________________________________________________ -->
4298<div class="doc_subsubsection">
4299 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4300</div>
4301<div class="doc_text">
4302
4303<h5>Syntax:</h5>
4304<pre>
4305 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4306</pre>
4307
4308<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4309<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4310 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4311
4312<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4313<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4314 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4315 <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]4316
4317<h5>Semantics:</h5>
4318<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4319 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4320 truncating or zero extending that value to the size of the integer type. If
4321 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4322 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4323 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4324 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4325
4326<h5>Example:</h5>
4327<pre>
4328 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4329 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4330</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4332</div>
4333
4334<!-- _______________________________________________________________________ -->
4335<div class="doc_subsubsection">
4336 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4337</div>
4338<div class="doc_text">
4339
4340<h5>Syntax:</h5>
4341<pre>
4342 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4343</pre>
4344
4345<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4346<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4347 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4348
4349<h5>Arguments:</h5>
4350<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4351 value to cast, and a type to cast it to, which must be a
4352 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4353
4354<h5>Semantics:</h5>
4355<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4356 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4357 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4358 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4359 than the size of a pointer then a zero extension is done. If they are the
4360 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4361
4362<h5>Example:</h5>
4363<pre>
4364 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4365 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4366 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4367</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369</div>
4370
4371<!-- _______________________________________________________________________ -->
4372<div class="doc_subsubsection">
4373 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4374</div>
4375<div class="doc_text">
4376
4377<h5>Syntax:</h5>
4378<pre>
4379 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4380</pre>
4381
4382<h5>Overview:</h5>
4383<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4384 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4385
4386<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4387<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4388 non-aggregate first class value, and a type to cast it to, which must also be
4389 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4390 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4391 identical. If the source type is a pointer, the destination type must also be
4392 a pointer. This instruction supports bitwise conversion of vectors to
4393 integers and to vectors of other types (as long as they have the same
4394 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4395
4396<h5>Semantics:</h5>
4397<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4398 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4399 this conversion. The conversion is done as if the <tt>value</tt> had been
4400 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4401 be converted to other pointer types with this instruction. To convert
4402 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4403 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4404
4405<h5>Example:</h5>
4406<pre>
4407 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4408 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4409 %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]4410</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4412</div>
4413
4414<!-- ======================================================================= -->
4415<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4417<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4418
4419<p>The instructions in this category are the "miscellaneous" instructions, which
4420 defy better classification.</p>
4421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4422</div>
4423
4424<!-- _______________________________________________________________________ -->
4425<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4426</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4428<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4431<pre>
4432 &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]4433</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4435<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4436<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4437 boolean values based on comparison of its two integer, integer vector, or
4438 pointer operands.</p>
4439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4440<h5>Arguments:</h5>
4441<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4442 the condition code indicating the kind of comparison to perform. It is not a
4443 value, just a keyword. The possible condition code are:</p>
4444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445<ol>
4446 <li><tt>eq</tt>: equal</li>
4447 <li><tt>ne</tt>: not equal </li>
4448 <li><tt>ugt</tt>: unsigned greater than</li>
4449 <li><tt>uge</tt>: unsigned greater or equal</li>
4450 <li><tt>ult</tt>: unsigned less than</li>
4451 <li><tt>ule</tt>: unsigned less or equal</li>
4452 <li><tt>sgt</tt>: signed greater than</li>
4453 <li><tt>sge</tt>: signed greater or equal</li>
4454 <li><tt>slt</tt>: signed less than</li>
4455 <li><tt>sle</tt>: signed less or equal</li>
4456</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4457
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4458<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4459 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4460 typed. They must also be identical types.</p>
4461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4462<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4463<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4464 condition code given as <tt>cond</tt>. The comparison performed always yields
4465 either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
4466 result, as follows:</p>
4467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468<ol>
4469 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4470 <tt>false</tt> otherwise. No sign interpretation is necessary or
4471 performed.</li>
4472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4474 <tt>false</tt> otherwise. No sign interpretation is necessary or
4475 performed.</li>
4476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4478 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4481 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4482 to <tt>op2</tt>.</li>
4483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4485 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4487 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4488 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4491 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4493 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4494 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4495 to <tt>op2</tt>.</li>
4496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4498 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4499
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4500 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4501 <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]4502</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4504<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4505 values are compared as if they were integers.</p>
4506
4507<p>If the operands are integer vectors, then they are compared element by
4508 element. The result is an <tt>i1</tt> vector with the same number of elements
4509 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510
4511<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4512<pre>
4513 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4514 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4515 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4516 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4517 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4518 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4519</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4520
4521<p>Note that the code generator does not yet support vector types with
4522 the <tt>icmp</tt> instruction.</p>
4523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4524</div>
4525
4526<!-- _______________________________________________________________________ -->
4527<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4528</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4530<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4532<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4533<pre>
4534 &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]4535</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4537<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4538<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4539 values based on comparison of its operands.</p>
4540
4541<p>If the operands are floating point scalars, then the result type is a boolean
4542(<a href="#t_primitive"><tt>i1</tt></a>).</p>
4543
4544<p>If the operands are floating point vectors, then the result type is a vector
4545 of boolean with the same number of elements as the operands being
4546 compared.</p>
4547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4548<h5>Arguments:</h5>
4549<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4550 the condition code indicating the kind of comparison to perform. It is not a
4551 value, just a keyword. The possible condition code are:</p>
4552
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4553<ol>
4554 <li><tt>false</tt>: no comparison, always returns false</li>
4555 <li><tt>oeq</tt>: ordered and equal</li>
4556 <li><tt>ogt</tt>: ordered and greater than </li>
4557 <li><tt>oge</tt>: ordered and greater than or equal</li>
4558 <li><tt>olt</tt>: ordered and less than </li>
4559 <li><tt>ole</tt>: ordered and less than or equal</li>
4560 <li><tt>one</tt>: ordered and not equal</li>
4561 <li><tt>ord</tt>: ordered (no nans)</li>
4562 <li><tt>ueq</tt>: unordered or equal</li>
4563 <li><tt>ugt</tt>: unordered or greater than </li>
4564 <li><tt>uge</tt>: unordered or greater than or equal</li>
4565 <li><tt>ult</tt>: unordered or less than </li>
4566 <li><tt>ule</tt>: unordered or less than or equal</li>
4567 <li><tt>une</tt>: unordered or not equal</li>
4568 <li><tt>uno</tt>: unordered (either nans)</li>
4569 <li><tt>true</tt>: no comparison, always returns true</li>
4570</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4572<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4573 <i>unordered</i> means that either operand may be a QNAN.</p>
4574
4575<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4576 a <a href="#t_floating">floating point</a> type or
4577 a <a href="#t_vector">vector</a> of floating point type. They must have
4578 identical types.</p>
4579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4580<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4581<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4582 according to the condition code given as <tt>cond</tt>. If the operands are
4583 vectors, then the vectors are compared element by element. Each comparison
4584 performed always yields an <a href="#t_primitive">i1</a> result, as
4585 follows:</p>
4586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587<ol>
4588 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4590 <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]4591 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4592
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4593 <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]4594 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4596 <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]4597 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4599 <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]4600 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602 <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]4603 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4605 <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]4606 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4608 <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]4609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610 <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]4611 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4613 <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]4614 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4616 <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]4617 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4619 <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]4620 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4621
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4622 <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]4623 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4624
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4625 <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]4626 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4628 <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]4629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4630 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4631</ol>
4632
4633<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4634<pre>
4635 &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]4636 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4637 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4638 &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]4639</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4640
4641<p>Note that the code generator does not yet support vector types with
4642 the <tt>fcmp</tt> instruction.</p>
4643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4644</div>
4645
4646<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4647<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4648 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4649</div>
4650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4654<pre>
4655 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4656</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4658<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4660 SSA graph representing the function.</p>
4661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4662<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4663<p>The type of the incoming values is specified with the first type field. After
4664 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4665 one pair for each predecessor basic block of the current block. Only values
4666 of <a href="#t_firstclass">first class</a> type may be used as the value
4667 arguments to the PHI node. Only labels may be used as the label
4668 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4669
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4670<p>There must be no non-phi instructions between the start of a basic block and
4671 the PHI instructions: i.e. PHI instructions must be first in a basic
4672 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4673
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4674<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4675 occur on the edge from the corresponding predecessor block to the current
4676 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4677 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4679<h5>Semantics:</h5>
4680<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4681 specified by the pair corresponding to the predecessor basic block that
4682 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4684<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4685<pre>
4686Loop: ; Infinite loop that counts from 0 on up...
4687 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4688 %nextindvar = add i32 %indvar, 1
4689 br label %Loop
4690</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4692</div>
4693
4694<!-- _______________________________________________________________________ -->
4695<div class="doc_subsubsection">
4696 <a name="i_select">'<tt>select</tt>' Instruction</a>
4697</div>
4698
4699<div class="doc_text">
4700
4701<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4702<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4703 &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>
4704
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4705 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4706</pre>
4707
4708<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4709<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4710 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4711
4712
4713<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4714<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4715 values indicating the condition, and two values of the
4716 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4717 vectors and the condition is a scalar, then entire vectors are selected, not
4718 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4719
4720<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4722 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724<p>If the condition is a vector of i1, then the value arguments must be vectors
4725 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726
4727<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4728<pre>
4729 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4730</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4731
4732<p>Note that the code generator does not yet support conditions
4733 with vector type.</p>
4734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4735</div>
4736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4737<!-- _______________________________________________________________________ -->
4738<div class="doc_subsubsection">
4739 <a name="i_call">'<tt>call</tt>' Instruction</a>
4740</div>
4741
4742<div class="doc_text">
4743
4744<h5>Syntax:</h5>
4745<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4746 &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]4747</pre>
4748
4749<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4750<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4751
4752<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753<p>This instruction requires several arguments:</p>
4754
4755<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4756 <li>The optional "tail" marker indicates whether the callee function accesses
4757 any allocas or varargs in the caller. If the "tail" marker is present,
4758 the function call is eligible for tail call optimization. Note that calls
4759 may be marked "tail" even if they do not occur before
4760 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4761
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4763 convention</a> the call should use. If none is specified, the call
4764 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4765
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4766 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4767 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4768 '<tt>inreg</tt>' attributes are valid here.</li>
4769
4770 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
4771 type of the return value. Functions that return no value are marked
4772 <tt><a href="#t_void">void</a></tt>.</li>
4773
4774 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
4775 being invoked. The argument types must match the types implied by this
4776 signature. This type can be omitted if the function is not varargs and if
4777 the function type does not return a pointer to a function.</li>
4778
4779 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4780 be invoked. In most cases, this is a direct function invocation, but
4781 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4782 to function value.</li>
4783
4784 <li>'<tt>function args</tt>': argument list whose types match the function
4785 signature argument types. All arguments must be of
4786 <a href="#t_firstclass">first class</a> type. If the function signature
4787 indicates the function accepts a variable number of arguments, the extra
4788 arguments can be specified.</li>
4789
4790 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
4791 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4792 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4793</ol>
4794
4795<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4796<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
4797 a specified function, with its incoming arguments bound to the specified
4798 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
4799 function, control flow continues with the instruction after the function
4800 call, and the return value of the function is bound to the result
4801 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802
4803<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4804<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4805 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4806 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4807 %X = tail call i32 @foo() <i>; yields i32</i>
4808 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4809 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4810
4811 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4812 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4813 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4814 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4815 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4816 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4817</pre>
4818
4819</div>
4820
4821<!-- _______________________________________________________________________ -->
4822<div class="doc_subsubsection">
4823 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4824</div>
4825
4826<div class="doc_text">
4827
4828<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4829<pre>
4830 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4831</pre>
4832
4833<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4834<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4835 the "variable argument" area of a function call. It is used to implement the
4836 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4837
4838<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4839<p>This instruction takes a <tt>va_list*</tt> value and the type of the
4840 argument. It returns a value of the specified argument type and increments
4841 the <tt>va_list</tt> to point to the next argument. The actual type
4842 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4843
4844<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4845<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
4846 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
4847 to the next argument. For more information, see the variable argument
4848 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4849
4850<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]4851 take a variable number of arguments, for example, the <tt>vfprintf</tt>
4852 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4853
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4854<p><tt>va_arg</tt> is an LLVM instruction instead of
4855 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
4856 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857
4858<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4859<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4860
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4861<p>Note that the code generator does not yet fully support va_arg on many
4862 targets. Also, it does not currently support va_arg with aggregate types on
4863 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4865</div>
4866
4867<!-- *********************************************************************** -->
4868<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4869<!-- *********************************************************************** -->
4870
4871<div class="doc_text">
4872
4873<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4874 well known names and semantics and are required to follow certain
4875 restrictions. Overall, these intrinsics represent an extension mechanism for
4876 the LLVM language that does not require changing all of the transformations
4877 in LLVM when adding to the language (or the bitcode reader/writer, the
4878 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4879
4880<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4881 prefix is reserved in LLVM for intrinsic names; thus, function names may not
4882 begin with this prefix. Intrinsic functions must always be external
4883 functions: you cannot define the body of intrinsic functions. Intrinsic
4884 functions may only be used in call or invoke instructions: it is illegal to
4885 take the address of an intrinsic function. Additionally, because intrinsic
4886 functions are part of the LLVM language, it is required if any are added that
4887 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4888
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4889<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
4890 family of functions that perform the same operation but on different data
4891 types. Because LLVM can represent over 8 million different integer types,
4892 overloading is used commonly to allow an intrinsic function to operate on any
4893 integer type. One or more of the argument types or the result type can be
4894 overloaded to accept any integer type. Argument types may also be defined as
4895 exactly matching a previous argument's type or the result type. This allows
4896 an intrinsic function which accepts multiple arguments, but needs all of them
4897 to be of the same type, to only be overloaded with respect to a single
4898 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4899
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4900<p>Overloaded intrinsics will have the names of its overloaded argument types
4901 encoded into its function name, each preceded by a period. Only those types
4902 which are overloaded result in a name suffix. Arguments whose type is matched
4903 against another type do not. For example, the <tt>llvm.ctpop</tt> function
4904 can take an integer of any width and returns an integer of exactly the same
4905 integer width. This leads to a family of functions such as
4906 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
4907 %val)</tt>. Only one type, the return type, is overloaded, and only one type
4908 suffix is required. Because the argument's type is matched against the return
4909 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4910
4911<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4912 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4913
4914</div>
4915
4916<!-- ======================================================================= -->
4917<div class="doc_subsection">
4918 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4919</div>
4920
4921<div class="doc_text">
4922
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4923<p>Variable argument support is defined in LLVM with
4924 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4925 intrinsic functions. These functions are related to the similarly named
4926 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4927
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4928<p>All of these functions operate on arguments that use a target-specific value
4929 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
4930 not define what this type is, so all transformations should be prepared to
4931 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4932
4933<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]4934 instruction and the variable argument handling intrinsic functions are
4935 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4936
4937<div class="doc_code">
4938<pre>
4939define i32 @test(i32 %X, ...) {
4940 ; Initialize variable argument processing
4941 %ap = alloca i8*
4942 %ap2 = bitcast i8** %ap to i8*
4943 call void @llvm.va_start(i8* %ap2)
4944
4945 ; Read a single integer argument
4946 %tmp = va_arg i8** %ap, i32
4947
4948 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4949 %aq = alloca i8*
4950 %aq2 = bitcast i8** %aq to i8*
4951 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4952 call void @llvm.va_end(i8* %aq2)
4953
4954 ; Stop processing of arguments.
4955 call void @llvm.va_end(i8* %ap2)
4956 ret i32 %tmp
4957}
4958
4959declare void @llvm.va_start(i8*)
4960declare void @llvm.va_copy(i8*, i8*)
4961declare void @llvm.va_end(i8*)
4962</pre>
4963</div>
4964
4965</div>
4966
4967<!-- _______________________________________________________________________ -->
4968<div class="doc_subsubsection">
4969 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4970</div>
4971
4972
4973<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4974
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4975<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4976<pre>
4977 declare void %llvm.va_start(i8* &lt;arglist&gt;)
4978</pre>
4979
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4980<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4981<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
4982 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]4983
4984<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4985<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]4986
4987<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4988<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]4989 macro available in C. In a target-dependent way, it initializes
4990 the <tt>va_list</tt> element to which the argument points, so that the next
4991 call to <tt>va_arg</tt> will produce the first variable argument passed to
4992 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
4993 need to know the last argument of the function as the compiler can figure
4994 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4995
4996</div>
4997
4998<!-- _______________________________________________________________________ -->
4999<div class="doc_subsubsection">
5000 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5001</div>
5002
5003<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5004
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5005<h5>Syntax:</h5>
5006<pre>
5007 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5008</pre>
5009
5010<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5012 which has been initialized previously
5013 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5014 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5015
5016<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5017<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5018
5019<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5020<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]5021 macro available in C. In a target-dependent way, it destroys
5022 the <tt>va_list</tt> element to which the argument points. Calls
5023 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5024 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5025 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5026
5027</div>
5028
5029<!-- _______________________________________________________________________ -->
5030<div class="doc_subsubsection">
5031 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5032</div>
5033
5034<div class="doc_text">
5035
5036<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5037<pre>
5038 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5039</pre>
5040
5041<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5042<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5043 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5044
5045<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5046<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]5047 The second argument is a pointer to a <tt>va_list</tt> element to copy
5048 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5049
5050<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5051<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]5052 macro available in C. In a target-dependent way, it copies the
5053 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5054 element. This intrinsic is necessary because
5055 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5056 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5057
5058</div>
5059
5060<!-- ======================================================================= -->
5061<div class="doc_subsection">
5062 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5063</div>
5064
5065<div class="doc_text">
5066
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5067<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5068Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5069intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5070roots on the stack</a>, as well as garbage collector implementations that
5071require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5072barriers. Front-ends for type-safe garbage collected languages should generate
5073these intrinsics to make use of the LLVM garbage collectors. For more details,
5074see <a href="GarbageCollection.html">Accurate Garbage Collection with
5075LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5076
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5077<p>The garbage collection intrinsics only operate on objects in the generic
5078 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5080</div>
5081
5082<!-- _______________________________________________________________________ -->
5083<div class="doc_subsubsection">
5084 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5085</div>
5086
5087<div class="doc_text">
5088
5089<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5090<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5091 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092</pre>
5093
5094<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5095<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]5096 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5097
5098<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5099<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5100 root pointer. The second pointer (which must be either a constant or a
5101 global value address) contains the meta-data to be associated with the
5102 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5103
5104<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5105<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]5106 location. At compile-time, the code generator generates information to allow
5107 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5108 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5109 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5110
5111</div>
5112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5113<!-- _______________________________________________________________________ -->
5114<div class="doc_subsubsection">
5115 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5116</div>
5117
5118<div class="doc_text">
5119
5120<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5122 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5123</pre>
5124
5125<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5126<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5127 locations, allowing garbage collector implementations that require read
5128 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5129
5130<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5131<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]5132 allocated from the garbage collector. The first object is a pointer to the
5133 start of the referenced object, if needed by the language runtime (otherwise
5134 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5135
5136<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5137<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5138 instruction, but may be replaced with substantially more complex code by the
5139 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5140 may only be used in a function which <a href="#gc">specifies a GC
5141 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142
5143</div>
5144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5145<!-- _______________________________________________________________________ -->
5146<div class="doc_subsubsection">
5147 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5148</div>
5149
5150<div class="doc_text">
5151
5152<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5153<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5154 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5155</pre>
5156
5157<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5158<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5159 locations, allowing garbage collector implementations that require write
5160 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5161
5162<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5163<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]5164 object to store it to, and the third is the address of the field of Obj to
5165 store to. If the runtime does not require a pointer to the object, Obj may
5166 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5167
5168<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5169<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5170 instruction, but may be replaced with substantially more complex code by the
5171 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5172 may only be used in a function which <a href="#gc">specifies a GC
5173 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5174
5175</div>
5176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5177<!-- ======================================================================= -->
5178<div class="doc_subsection">
5179 <a name="int_codegen">Code Generator Intrinsics</a>
5180</div>
5181
5182<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5183
5184<p>These intrinsics are provided by LLVM to expose special features that may
5185 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5186
5187</div>
5188
5189<!-- _______________________________________________________________________ -->
5190<div class="doc_subsubsection">
5191 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5192</div>
5193
5194<div class="doc_text">
5195
5196<h5>Syntax:</h5>
5197<pre>
5198 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5199</pre>
5200
5201<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5202<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5203 target-specific value indicating the return address of the current function
5204 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5205
5206<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5207<p>The argument to this intrinsic indicates which function to return the address
5208 for. Zero indicates the calling function, one indicates its caller, etc.
5209 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5210
5211<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5212<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5213 indicating the return address of the specified call frame, or zero if it
5214 cannot be identified. The value returned by this intrinsic is likely to be
5215 incorrect or 0 for arguments other than zero, so it should only be used for
5216 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5217
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5218<p>Note that calling this intrinsic does not prevent function inlining or other
5219 aggressive transformations, so the value returned may not be that of the
5220 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5222</div>
5223
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224<!-- _______________________________________________________________________ -->
5225<div class="doc_subsubsection">
5226 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5227</div>
5228
5229<div class="doc_text">
5230
5231<h5>Syntax:</h5>
5232<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5233 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5234</pre>
5235
5236<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5237<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5238 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5239
5240<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5241<p>The argument to this intrinsic indicates which function to return the frame
5242 pointer for. Zero indicates the calling function, one indicates its caller,
5243 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5244
5245<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5246<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5247 indicating the frame address of the specified call frame, or zero if it
5248 cannot be identified. The value returned by this intrinsic is likely to be
5249 incorrect or 0 for arguments other than zero, so it should only be used for
5250 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5251
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5252<p>Note that calling this intrinsic does not prevent function inlining or other
5253 aggressive transformations, so the value returned may not be that of the
5254 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5256</div>
5257
5258<!-- _______________________________________________________________________ -->
5259<div class="doc_subsubsection">
5260 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5261</div>
5262
5263<div class="doc_text">
5264
5265<h5>Syntax:</h5>
5266<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5267 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5268</pre>
5269
5270<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5271<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5272 of the function stack, for use
5273 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5274 useful for implementing language features like scoped automatic variable
5275 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5276
5277<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5278<p>This intrinsic returns a opaque pointer value that can be passed
5279 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5280 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5281 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5282 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5283 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5284 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285
5286</div>
5287
5288<!-- _______________________________________________________________________ -->
5289<div class="doc_subsubsection">
5290 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5291</div>
5292
5293<div class="doc_text">
5294
5295<h5>Syntax:</h5>
5296<pre>
5297 declare void @llvm.stackrestore(i8 * %ptr)
5298</pre>
5299
5300<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5301<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5302 the function stack to the state it was in when the
5303 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5304 executed. This is useful for implementing language features like scoped
5305 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5306
5307<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5308<p>See the description
5309 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5310
5311</div>
5312
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5313<!-- _______________________________________________________________________ -->
5314<div class="doc_subsubsection">
5315 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5316</div>
5317
5318<div class="doc_text">
5319
5320<h5>Syntax:</h5>
5321<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5322 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]5323</pre>
5324
5325<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5326<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5327 insert a prefetch instruction if supported; otherwise, it is a noop.
5328 Prefetches have no effect on the behavior of the program but can change its
5329 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5330
5331<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5332<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5333 specifier determining if the fetch should be for a read (0) or write (1),
5334 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5335 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5336 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5337
5338<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5339<p>This intrinsic does not modify the behavior of the program. In particular,
5340 prefetches cannot trap and do not produce a value. On targets that support
5341 this intrinsic, the prefetch can provide hints to the processor cache for
5342 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5343
5344</div>
5345
5346<!-- _______________________________________________________________________ -->
5347<div class="doc_subsubsection">
5348 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5349</div>
5350
5351<div class="doc_text">
5352
5353<h5>Syntax:</h5>
5354<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5355 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5356</pre>
5357
5358<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5359<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5360 Counter (PC) in a region of code to simulators and other tools. The method
5361 is target specific, but it is expected that the marker will use exported
5362 symbols to transmit the PC of the marker. The marker makes no guarantees
5363 that it will remain with any specific instruction after optimizations. It is
5364 possible that the presence of a marker will inhibit optimizations. The
5365 intended use is to be inserted after optimizations to allow correlations of
5366 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5367
5368<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5369<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5370
5371<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5372<p>This intrinsic does not modify the behavior of the program. Backends that do
5373 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374
5375</div>
5376
5377<!-- _______________________________________________________________________ -->
5378<div class="doc_subsubsection">
5379 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5380</div>
5381
5382<div class="doc_text">
5383
5384<h5>Syntax:</h5>
5385<pre>
5386 declare i64 @llvm.readcyclecounter( )
5387</pre>
5388
5389<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5390<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5391 counter register (or similar low latency, high accuracy clocks) on those
5392 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5393 should map to RPCC. As the backing counters overflow quickly (on the order
5394 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395
5396<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5397<p>When directly supported, reading the cycle counter should not modify any
5398 memory. Implementations are allowed to either return a application specific
5399 value or a system wide value. On backends without support, this is lowered
5400 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5401
5402</div>
5403
5404<!-- ======================================================================= -->
5405<div class="doc_subsection">
5406 <a name="int_libc">Standard C Library Intrinsics</a>
5407</div>
5408
5409<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5410
5411<p>LLVM provides intrinsics for a few important standard C library functions.
5412 These intrinsics allow source-language front-ends to pass information about
5413 the alignment of the pointer arguments to the code generator, providing
5414 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5415
5416</div>
5417
5418<!-- _______________________________________________________________________ -->
5419<div class="doc_subsubsection">
5420 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5421</div>
5422
5423<div class="doc_text">
5424
5425<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5426<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5427 integer bit width. Not all targets support all bit widths however.</p>
5428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5429<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5430 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5431 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5432 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5433 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5435 i32 &lt;len&gt;, i32 &lt;align&gt;)
5436 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5437 i64 &lt;len&gt;, i32 &lt;align&gt;)
5438</pre>
5439
5440<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5442 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5443
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5444<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5445 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446
5447<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5448<p>The first argument is a pointer to the destination, the second is a pointer
5449 to the source. The third argument is an integer argument specifying the
5450 number of bytes to copy, and the fourth argument is the alignment of the
5451 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5452
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5453<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5454 then the caller guarantees that both the source and destination pointers are
5455 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5456
5457<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5458<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5459 source location to the destination location, which are not allowed to
5460 overlap. It copies "len" bytes of memory over. If the argument is known to
5461 be aligned to some boundary, this can be specified as the fourth argument,
5462 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5464</div>
5465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5466<!-- _______________________________________________________________________ -->
5467<div class="doc_subsubsection">
5468 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5469</div>
5470
5471<div class="doc_text">
5472
5473<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5474<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]5475 width. Not all targets support all bit widths however.</p>
5476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5477<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5478 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5479 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5480 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5481 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5482 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5483 i32 &lt;len&gt;, i32 &lt;align&gt;)
5484 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5485 i64 &lt;len&gt;, i32 &lt;align&gt;)
5486</pre>
5487
5488<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5489<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5490 source location to the destination location. It is similar to the
5491 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5492 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5493
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5494<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5495 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5496
5497<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5498<p>The first argument is a pointer to the destination, the second is a pointer
5499 to the source. The third argument is an integer argument specifying the
5500 number of bytes to copy, and the fourth argument is the alignment of the
5501 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5503<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5504 then the caller guarantees that the source and destination pointers are
5505 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5506
5507<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5508<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5509 source location to the destination location, which may overlap. It copies
5510 "len" bytes of memory over. If the argument is known to be aligned to some
5511 boundary, this can be specified as the fourth argument, otherwise it should
5512 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514</div>
5515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516<!-- _______________________________________________________________________ -->
5517<div class="doc_subsubsection">
5518 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5519</div>
5520
5521<div class="doc_text">
5522
5523<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5524<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]5525 width. Not all targets support all bit widths however.</p>
5526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5527<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5528 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5529 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5530 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5531 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5532 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5533 i32 &lt;len&gt;, i32 &lt;align&gt;)
5534 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5535 i64 &lt;len&gt;, i32 &lt;align&gt;)
5536</pre>
5537
5538<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5539<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5540 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5541
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5542<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5543 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5544
5545<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5546<p>The first argument is a pointer to the destination to fill, the second is the
5547 byte value to fill it with, the third argument is an integer argument
5548 specifying the number of bytes to fill, and the fourth argument is the known
5549 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5550
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5551<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5552 then the caller guarantees that the destination pointer is aligned to that
5553 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554
5555<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5556<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5557 at the destination location. If the argument is known to be aligned to some
5558 boundary, this can be specified as the fourth argument, otherwise it should
5559 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5561</div>
5562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5563<!-- _______________________________________________________________________ -->
5564<div class="doc_subsubsection">
5565 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5566</div>
5567
5568<div class="doc_text">
5569
5570<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5571<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5572 floating point or vector of floating point type. Not all targets support all
5573 types however.</p>
5574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5575<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5576 declare float @llvm.sqrt.f32(float %Val)
5577 declare double @llvm.sqrt.f64(double %Val)
5578 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5579 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5580 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5581</pre>
5582
5583<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5584<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5585 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5586 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5587 behavior for negative numbers other than -0.0 (which allows for better
5588 optimization, because there is no need to worry about errno being
5589 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]5590
5591<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5592<p>The argument and return value are floating point numbers of the same
5593 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5594
5595<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5596<p>This function returns the sqrt of the specified operand if it is a
5597 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5599</div>
5600
5601<!-- _______________________________________________________________________ -->
5602<div class="doc_subsubsection">
5603 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5604</div>
5605
5606<div class="doc_text">
5607
5608<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5609<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5610 floating point or vector of floating point type. Not all targets support all
5611 types however.</p>
5612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5613<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5614 declare float @llvm.powi.f32(float %Val, i32 %power)
5615 declare double @llvm.powi.f64(double %Val, i32 %power)
5616 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5617 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5618 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5619</pre>
5620
5621<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5622<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5623 specified (positive or negative) power. The order of evaluation of
5624 multiplications is not defined. When a vector of floating point type is
5625 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5626
5627<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5628<p>The second argument is an integer power, and the first is a value to raise to
5629 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5630
5631<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5632<p>This function returns the first value raised to the second power with an
5633 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635</div>
5636
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5637<!-- _______________________________________________________________________ -->
5638<div class="doc_subsubsection">
5639 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5640</div>
5641
5642<div class="doc_text">
5643
5644<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5645<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5646 floating point or vector of floating point type. Not all targets support all
5647 types however.</p>
5648
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5649<pre>
5650 declare float @llvm.sin.f32(float %Val)
5651 declare double @llvm.sin.f64(double %Val)
5652 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5653 declare fp128 @llvm.sin.f128(fp128 %Val)
5654 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5655</pre>
5656
5657<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5658<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5659
5660<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5661<p>The argument and return value are floating point numbers of the same
5662 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5663
5664<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5665<p>This function returns the sine of the specified operand, returning the same
5666 values as the libm <tt>sin</tt> functions would, and handles error conditions
5667 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5668
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5669</div>
5670
5671<!-- _______________________________________________________________________ -->
5672<div class="doc_subsubsection">
5673 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5674</div>
5675
5676<div class="doc_text">
5677
5678<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5679<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5680 floating point or vector of floating point type. Not all targets support all
5681 types however.</p>
5682
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5683<pre>
5684 declare float @llvm.cos.f32(float %Val)
5685 declare double @llvm.cos.f64(double %Val)
5686 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5687 declare fp128 @llvm.cos.f128(fp128 %Val)
5688 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5689</pre>
5690
5691<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5692<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5693
5694<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5695<p>The argument and return value are floating point numbers of the same
5696 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5697
5698<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5699<p>This function returns the cosine of the specified operand, returning the same
5700 values as the libm <tt>cos</tt> functions would, and handles error conditions
5701 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5702
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5703</div>
5704
5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
5707 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5713<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5714 floating point or vector of floating point type. Not all targets support all
5715 types however.</p>
5716
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5717<pre>
5718 declare float @llvm.pow.f32(float %Val, float %Power)
5719 declare double @llvm.pow.f64(double %Val, double %Power)
5720 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5721 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5722 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5723</pre>
5724
5725<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5726<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5727 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5728
5729<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5730<p>The second argument is a floating point power, and the first is a value to
5731 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5732
5733<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5734<p>This function returns the first value raised to the second power, returning
5735 the same values as the libm <tt>pow</tt> functions would, and handles error
5736 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5737
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5738</div>
5739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5740<!-- ======================================================================= -->
5741<div class="doc_subsection">
5742 <a name="int_manip">Bit Manipulation Intrinsics</a>
5743</div>
5744
5745<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5746
5747<p>LLVM provides intrinsics for a few important bit manipulation operations.
5748 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5749
5750</div>
5751
5752<!-- _______________________________________________________________________ -->
5753<div class="doc_subsubsection">
5754 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5755</div>
5756
5757<div class="doc_text">
5758
5759<h5>Syntax:</h5>
5760<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5761 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5763<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5764 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5765 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5766 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5767</pre>
5768
5769<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5770<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5771 values with an even number of bytes (positive multiple of 16 bits). These
5772 are useful for performing operations on data that is not in the target's
5773 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5774
5775<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5776<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
5777 and low byte of the input i16 swapped. Similarly,
5778 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
5779 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
5780 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
5781 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
5782 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
5783 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5784
5785</div>
5786
5787<!-- _______________________________________________________________________ -->
5788<div class="doc_subsubsection">
5789 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5790</div>
5791
5792<div class="doc_text">
5793
5794<h5>Syntax:</h5>
5795<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]5796 width. Not all targets support all bit widths however.</p>
5797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5799 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5800 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5801 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5802 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5803 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804</pre>
5805
5806<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5807<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
5808 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809
5810<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5811<p>The only argument is the value to be counted. The argument may be of any
5812 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5813
5814<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5815<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]5816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5817</div>
5818
5819<!-- _______________________________________________________________________ -->
5820<div class="doc_subsubsection">
5821 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5822</div>
5823
5824<div class="doc_text">
5825
5826<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5827<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
5828 integer bit width. Not all targets support all bit widths however.</p>
5829
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5830<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5831 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5832 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5833 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5834 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5835 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836</pre>
5837
5838<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5839<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5840 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5841
5842<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5843<p>The only argument is the value to be counted. The argument may be of any
5844 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5845
5846<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
5848 zeros in a variable. If the src == 0 then the result is the size in bits of
5849 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5851</div>
5852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5853<!-- _______________________________________________________________________ -->
5854<div class="doc_subsubsection">
5855 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5856</div>
5857
5858<div class="doc_text">
5859
5860<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5861<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
5862 integer bit width. Not all targets support all bit widths however.</p>
5863
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5864<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5865 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5866 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5867 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5868 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5869 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5870</pre>
5871
5872<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5873<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5874 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5875
5876<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5877<p>The only argument is the value to be counted. The argument may be of any
5878 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5879
5880<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5881<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
5882 zeros in a variable. If the src == 0 then the result is the size in bits of
5883 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5885</div>
5886
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5887<!-- ======================================================================= -->
5888<div class="doc_subsection">
5889 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5890</div>
5891
5892<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5893
5894<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5895
5896</div>
5897
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5898<!-- _______________________________________________________________________ -->
5899<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5900 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5901</div>
5902
5903<div class="doc_text">
5904
5905<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5906<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]5907 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5908
5909<pre>
5910 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5911 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5912 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5913</pre>
5914
5915<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5916<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5917 a signed addition of the two arguments, and indicate whether an overflow
5918 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5919
5920<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5921<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]5922 be of integer types of any bit width, but they must have the same bit
5923 width. The second element of the result structure must be of
5924 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5925 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5926
5927<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5928<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5929 a signed addition of the two variables. They return a structure &mdash; the
5930 first element of which is the signed summation, and the second element of
5931 which is a bit specifying if the signed summation resulted in an
5932 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5933
5934<h5>Examples:</h5>
5935<pre>
5936 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5937 %sum = extractvalue {i32, i1} %res, 0
5938 %obit = extractvalue {i32, i1} %res, 1
5939 br i1 %obit, label %overflow, label %normal
5940</pre>
5941
5942</div>
5943
5944<!-- _______________________________________________________________________ -->
5945<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5946 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5947</div>
5948
5949<div class="doc_text">
5950
5951<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5952<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]5953 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5954
5955<pre>
5956 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
5957 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5958 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
5959</pre>
5960
5961<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5962<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5963 an unsigned addition of the two arguments, and indicate whether a carry
5964 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5965
5966<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5967<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]5968 be of integer types of any bit width, but they must have the same bit
5969 width. The second element of the result structure must be of
5970 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
5971 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5972
5973<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5974<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5975 an unsigned addition of the two arguments. They return a structure &mdash;
5976 the first element of which is the sum, and the second element of which is a
5977 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5978
5979<h5>Examples:</h5>
5980<pre>
5981 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
5982 %sum = extractvalue {i32, i1} %res, 0
5983 %obit = extractvalue {i32, i1} %res, 1
5984 br i1 %obit, label %carry, label %normal
5985</pre>
5986
5987</div>
5988
5989<!-- _______________________________________________________________________ -->
5990<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5991 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5992</div>
5993
5994<div class="doc_text">
5995
5996<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5997<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]5998 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5999
6000<pre>
6001 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6002 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6003 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6004</pre>
6005
6006<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6007<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6008 a signed subtraction of the two arguments, and indicate whether an overflow
6009 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6010
6011<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6012<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]6013 be of integer types of any bit width, but they must have the same bit
6014 width. The second element of the result structure must be of
6015 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6016 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6017
6018<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6019<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6020 a signed subtraction of the two arguments. They return a structure &mdash;
6021 the first element of which is the subtraction, and the second element of
6022 which is a bit specifying if the signed subtraction resulted in an
6023 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6024
6025<h5>Examples:</h5>
6026<pre>
6027 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6028 %sum = extractvalue {i32, i1} %res, 0
6029 %obit = extractvalue {i32, i1} %res, 1
6030 br i1 %obit, label %overflow, label %normal
6031</pre>
6032
6033</div>
6034
6035<!-- _______________________________________________________________________ -->
6036<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6037 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6038</div>
6039
6040<div class="doc_text">
6041
6042<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6043<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]6044 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6045
6046<pre>
6047 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6048 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6049 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6050</pre>
6051
6052<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6053<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6054 an unsigned subtraction of the two arguments, and indicate whether an
6055 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6056
6057<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6058<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]6059 be of integer types of any bit width, but they must have the same bit
6060 width. The second element of the result structure must be of
6061 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6062 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6063
6064<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6065<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6066 an unsigned subtraction of the two arguments. They return a structure &mdash;
6067 the first element of which is the subtraction, and the second element of
6068 which is a bit specifying if the unsigned subtraction resulted in an
6069 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6070
6071<h5>Examples:</h5>
6072<pre>
6073 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6074 %sum = extractvalue {i32, i1} %res, 0
6075 %obit = extractvalue {i32, i1} %res, 1
6076 br i1 %obit, label %overflow, label %normal
6077</pre>
6078
6079</div>
6080
6081<!-- _______________________________________________________________________ -->
6082<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6083 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6084</div>
6085
6086<div class="doc_text">
6087
6088<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6089<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]6090 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6091
6092<pre>
6093 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6094 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6095 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6096</pre>
6097
6098<h5>Overview:</h5>
6099
6100<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6101 a signed multiplication of the two arguments, and indicate whether an
6102 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6103
6104<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6105<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]6106 be of integer types of any bit width, but they must have the same bit
6107 width. The second element of the result structure must be of
6108 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6109 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6110
6111<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6112<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6113 a signed multiplication of the two arguments. They return a structure &mdash;
6114 the first element of which is the multiplication, and the second element of
6115 which is a bit specifying if the signed multiplication resulted in an
6116 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6117
6118<h5>Examples:</h5>
6119<pre>
6120 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6121 %sum = extractvalue {i32, i1} %res, 0
6122 %obit = extractvalue {i32, i1} %res, 1
6123 br i1 %obit, label %overflow, label %normal
6124</pre>
6125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6126</div>
6127
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6128<!-- _______________________________________________________________________ -->
6129<div class="doc_subsubsection">
6130 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6131</div>
6132
6133<div class="doc_text">
6134
6135<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6136<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]6137 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6138
6139<pre>
6140 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6141 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6142 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6143</pre>
6144
6145<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6146<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6147 a unsigned multiplication of the two arguments, and indicate whether an
6148 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6149
6150<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6151<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]6152 be of integer types of any bit width, but they must have the same bit
6153 width. The second element of the result structure must be of
6154 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6155 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6156
6157<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6158<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6159 an unsigned multiplication of the two arguments. They return a structure
6160 &mdash; the first element of which is the multiplication, and the second
6161 element of which is a bit specifying if the unsigned multiplication resulted
6162 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6163
6164<h5>Examples:</h5>
6165<pre>
6166 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6167 %sum = extractvalue {i32, i1} %res, 0
6168 %obit = extractvalue {i32, i1} %res, 1
6169 br i1 %obit, label %overflow, label %normal
6170</pre>
6171
6172</div>
6173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6174<!-- ======================================================================= -->
6175<div class="doc_subsection">
6176 <a name="int_debugger">Debugger Intrinsics</a>
6177</div>
6178
6179<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6180
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6181<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6182 prefix), are described in
6183 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6184 Level Debugging</a> document.</p>
6185
6186</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6187
6188<!-- ======================================================================= -->
6189<div class="doc_subsection">
6190 <a name="int_eh">Exception Handling Intrinsics</a>
6191</div>
6192
6193<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6194
6195<p>The LLVM exception handling intrinsics (which all start with
6196 <tt>llvm.eh.</tt> prefix), are described in
6197 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6198 Handling</a> document.</p>
6199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6200</div>
6201
6202<!-- ======================================================================= -->
6203<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6204 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6205</div>
6206
6207<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6208
6209<p>This intrinsic makes it possible to excise one parameter, marked with
6210 the <tt>nest</tt> attribute, from a function. The result is a callable
6211 function pointer lacking the nest parameter - the caller does not need to
6212 provide a value for it. Instead, the value to use is stored in advance in a
6213 "trampoline", a block of memory usually allocated on the stack, which also
6214 contains code to splice the nest value into the argument list. This is used
6215 to implement the GCC nested function address extension.</p>
6216
6217<p>For example, if the function is
6218 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6219 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6220 follows:</p>
6221
6222<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6223<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6224 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6225 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6226 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6227 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6228</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6229</div>
6230
6231<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6232 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6233
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6234</div>
6235
6236<!-- _______________________________________________________________________ -->
6237<div class="doc_subsubsection">
6238 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6239</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6240
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6241<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6242
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6243<h5>Syntax:</h5>
6244<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6245 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]6246</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6247
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6248<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6249<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6250 function pointer suitable for executing it.</p>
6251
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6252<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6253<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6254 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6255 sufficiently aligned block of memory; this memory is written to by the
6256 intrinsic. Note that the size and the alignment are target-specific - LLVM
6257 currently provides no portable way of determining them, so a front-end that
6258 generates this intrinsic needs to have some target-specific knowledge.
6259 The <tt>func</tt> argument must hold a function bitcast to
6260 an <tt>i8*</tt>.</p>
6261
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6262<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6263<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6264 dependent code, turning it into a function. A pointer to this function is
6265 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6266 function pointer type</a> before being called. The new function's signature
6267 is the same as that of <tt>func</tt> with any arguments marked with
6268 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6269 is allowed, and it must be of pointer type. Calling the new function is
6270 equivalent to calling <tt>func</tt> with the same argument list, but
6271 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6272 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6273 by <tt>tramp</tt> is modified, then the effect of any later call to the
6274 returned function pointer is undefined.</p>
6275
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6276</div>
6277
6278<!-- ======================================================================= -->
6279<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6280 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6281</div>
6282
6283<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6284
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6285<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6286 hardware constructs for atomic operations and memory synchronization. This
6287 provides an interface to the hardware, not an interface to the programmer. It
6288 is aimed at a low enough level to allow any programming models or APIs
6289 (Application Programming Interfaces) which need atomic behaviors to map
6290 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6291 hardware provides a "universal IR" for source languages, it also provides a
6292 starting point for developing a "universal" atomic operation and
6293 synchronization IR.</p>
6294
6295<p>These do <em>not</em> form an API such as high-level threading libraries,
6296 software transaction memory systems, atomic primitives, and intrinsic
6297 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6298 application libraries. The hardware interface provided by LLVM should allow
6299 a clean implementation of all of these APIs and parallel programming models.
6300 No one model or paradigm should be selected above others unless the hardware
6301 itself ubiquitously does so.</p>
6302
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6303</div>
6304
6305<!-- _______________________________________________________________________ -->
6306<div class="doc_subsubsection">
6307 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6308</div>
6309<div class="doc_text">
6310<h5>Syntax:</h5>
6311<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6312 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]6313</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6314
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6315<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6316<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6317 specific pairs of memory access types.</p>
6318
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6319<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6320<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6321 The first four arguments enables a specific barrier as listed below. The
6322 fith argument specifies that the barrier applies to io or device or uncached
6323 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6324
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6325<ul>
6326 <li><tt>ll</tt>: load-load barrier</li>
6327 <li><tt>ls</tt>: load-store barrier</li>
6328 <li><tt>sl</tt>: store-load barrier</li>
6329 <li><tt>ss</tt>: store-store barrier</li>
6330 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6331</ul>
6332
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6333<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6334<p>This intrinsic causes the system to enforce some ordering constraints upon
6335 the loads and stores of the program. This barrier does not
6336 indicate <em>when</em> any events will occur, it only enforces
6337 an <em>order</em> in which they occur. For any of the specified pairs of load
6338 and store operations (f.ex. load-load, or store-load), all of the first
6339 operations preceding the barrier will complete before any of the second
6340 operations succeeding the barrier begin. Specifically the semantics for each
6341 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6342
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6343<ul>
6344 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6345 after the barrier begins.</li>
6346 <li><tt>ls</tt>: All loads before the barrier must complete before any
6347 store after the barrier begins.</li>
6348 <li><tt>ss</tt>: All stores before the barrier must complete before any
6349 store after the barrier begins.</li>
6350 <li><tt>sl</tt>: All stores before the barrier must complete before any
6351 load after the barrier begins.</li>
6352</ul>
6353
6354<p>These semantics are applied with a logical "and" behavior when more than one
6355 is enabled in a single memory barrier intrinsic.</p>
6356
6357<p>Backends may implement stronger barriers than those requested when they do
6358 not support as fine grained a barrier as requested. Some architectures do
6359 not need all types of barriers and on such architectures, these become
6360 noops.</p>
6361
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6362<h5>Example:</h5>
6363<pre>
6364%ptr = malloc i32
6365 store i32 4, %ptr
6366
6367%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6368 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6369 <i>; guarantee the above finishes</i>
6370 store i32 8, %ptr <i>; before this begins</i>
6371</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6372
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6373</div>
6374
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6375<!-- _______________________________________________________________________ -->
6376<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6377 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6378</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6379
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6380<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6381
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6382<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6383<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6384 any integer bit width and for different address spaces. Not all targets
6385 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6386
6387<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6388 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6389 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6390 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6391 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]6392</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6393
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6394<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6395<p>This loads a value in memory and compares it to a given value. If they are
6396 equal, it stores a new value into the memory.</p>
6397
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6398<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6399<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6400 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6401 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6402 this integer type. While any bit width integer may be used, targets may only
6403 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6404
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6405<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6406<p>This entire intrinsic must be executed atomically. It first loads the value
6407 in memory pointed to by <tt>ptr</tt> and compares it with the
6408 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6409 memory. The loaded value is yielded in all cases. This provides the
6410 equivalent of an atomic compare-and-swap operation within the SSA
6411 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6412
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6413<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6414<pre>
6415%ptr = malloc i32
6416 store i32 4, %ptr
6417
6418%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6419%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6420 <i>; yields {i32}:result1 = 4</i>
6421%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6422%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6423
6424%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6425%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6426 <i>; yields {i32}:result2 = 8</i>
6427%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6428
6429%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6430</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6431
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6432</div>
6433
6434<!-- _______________________________________________________________________ -->
6435<div class="doc_subsubsection">
6436 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6437</div>
6438<div class="doc_text">
6439<h5>Syntax:</h5>
6440
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6441<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6442 integer bit width. Not all targets support all bit widths however.</p>
6443
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6444<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6445 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6446 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6447 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6448 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]6449</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6450
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6451<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6452<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6453 the value from memory. It then stores the value in <tt>val</tt> in the memory
6454 at <tt>ptr</tt>.</p>
6455
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6456<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6457<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6458 the <tt>val</tt> argument and the result must be integers of the same bit
6459 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6460 integer type. The targets may only lower integer representations they
6461 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6462
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6463<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6464<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6465 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6466 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6467
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6468<h5>Examples:</h5>
6469<pre>
6470%ptr = malloc i32
6471 store i32 4, %ptr
6472
6473%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6474%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6475 <i>; yields {i32}:result1 = 4</i>
6476%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6477%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6478
6479%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6480%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6481 <i>; yields {i32}:result2 = 8</i>
6482
6483%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6484%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6485</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6486
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6487</div>
6488
6489<!-- _______________________________________________________________________ -->
6490<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6491 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6492
6493</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6494
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6495<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6496
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6497<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6498<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6499 any integer bit width. Not all targets support all bit widths however.</p>
6500
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6501<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6502 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6503 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6504 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6505 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]6506</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6508<h5>Overview:</h5>
6509<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6510 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6511
6512<h5>Arguments:</h5>
6513<p>The intrinsic takes two arguments, the first a pointer to an integer value
6514 and the second an integer value. The result is also an integer value. These
6515 integer types can have any bit width, but they must all have the same bit
6516 width. The targets may only lower integer representations they support.</p>
6517
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6518<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6519<p>This intrinsic does a series of operations atomically. It first loads the
6520 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6521 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]6522
6523<h5>Examples:</h5>
6524<pre>
6525%ptr = malloc i32
6526 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6527%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6528 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6529%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6530 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6531%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6532 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6533%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6534</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6535
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6536</div>
6537
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6538<!-- _______________________________________________________________________ -->
6539<div class="doc_subsubsection">
6540 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6541
6542</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6543
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6544<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6545
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6546<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6547<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6548 any integer bit width and for different address spaces. Not all targets
6549 support all bit widths however.</p>
6550
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6551<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6552 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6553 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6554 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6555 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]6556</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6557
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6558<h5>Overview:</h5>
6559<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6560 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6561
6562<h5>Arguments:</h5>
6563<p>The intrinsic takes two arguments, the first a pointer to an integer value
6564 and the second an integer value. The result is also an integer value. These
6565 integer types can have any bit width, but they must all have the same bit
6566 width. The targets may only lower integer representations they support.</p>
6567
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6568<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6569<p>This intrinsic does a series of operations atomically. It first loads the
6570 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6571 result to <tt>ptr</tt>. It yields the original value stored
6572 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6573
6574<h5>Examples:</h5>
6575<pre>
6576%ptr = malloc i32
6577 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6578%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6579 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6580%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6581 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6582%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6583 <i>; yields {i32}:result3 = 2</i>
6584%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6585</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6586
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6587</div>
6588
6589<!-- _______________________________________________________________________ -->
6590<div class="doc_subsubsection">
6591 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6592 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6593 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6594 <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]6595</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6596
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6597<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6598
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6599<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6600<p>These are overloaded intrinsics. You can
6601 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6602 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6603 bit width and for different address spaces. Not all targets support all bit
6604 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6605
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6606<pre>
6607 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6608 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6609 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6610 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]6611</pre>
6612
6613<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6614 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6615 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6616 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6617 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]6618</pre>
6619
6620<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6621 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6622 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6623 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6624 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]6625</pre>
6626
6627<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6628 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6629 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6630 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6631 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]6632</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6633
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6634<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6635<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6636 the value stored in memory at <tt>ptr</tt>. It yields the original value
6637 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6638
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6639<h5>Arguments:</h5>
6640<p>These intrinsics take two arguments, the first a pointer to an integer value
6641 and the second an integer value. The result is also an integer value. These
6642 integer types can have any bit width, but they must all have the same bit
6643 width. The targets may only lower integer representations they support.</p>
6644
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6645<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6646<p>These intrinsics does a series of operations atomically. They first load the
6647 value stored at <tt>ptr</tt>. They then do the bitwise
6648 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6649 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6650
6651<h5>Examples:</h5>
6652<pre>
6653%ptr = malloc i32
6654 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6655%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6656 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6657%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6658 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6659%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6660 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6661%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6662 <i>; yields {i32}:result3 = FF</i>
6663%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6664</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6665
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6666</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6667
6668<!-- _______________________________________________________________________ -->
6669<div class="doc_subsubsection">
6670 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6671 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6672 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6673 <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]6674</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6675
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6676<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6677
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6678<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6679<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6680 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6681 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6682 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6683
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6684<pre>
6685 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6686 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6687 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6688 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]6689</pre>
6690
6691<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6692 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6693 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6694 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6695 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]6696</pre>
6697
6698<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6699 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6700 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6701 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6702 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]6703</pre>
6704
6705<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6706 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6707 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6708 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6709 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]6710</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6711
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6712<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6713<p>These intrinsics takes the signed or unsigned minimum or maximum of
6714 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6715 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6716
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6717<h5>Arguments:</h5>
6718<p>These intrinsics take two arguments, the first a pointer to an integer value
6719 and the second an integer value. The result is also an integer value. These
6720 integer types can have any bit width, but they must all have the same bit
6721 width. The targets may only lower integer representations they support.</p>
6722
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6723<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6724<p>These intrinsics does a series of operations atomically. They first load the
6725 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6726 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6727 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6728
6729<h5>Examples:</h5>
6730<pre>
6731%ptr = malloc i32
6732 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6733%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6734 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6735%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6736 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6737%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6738 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6739%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6740 <i>; yields {i32}:result3 = 8</i>
6741%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6742</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6743
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6744</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6745
6746<!-- ======================================================================= -->
6747<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6748 <a name="int_general">General Intrinsics</a>
6749</div>
6750
6751<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6752
6753<p>This class of intrinsics is designed to be generic and has no specific
6754 purpose.</p>
6755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6756</div>
6757
6758<!-- _______________________________________________________________________ -->
6759<div class="doc_subsubsection">
6760 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6761</div>
6762
6763<div class="doc_text">
6764
6765<h5>Syntax:</h5>
6766<pre>
6767 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6768</pre>
6769
6770<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6771<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6772
6773<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6774<p>The first argument is a pointer to a value, the second is a pointer to a
6775 global string, the third is a pointer to a global string which is the source
6776 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6777
6778<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6779<p>This intrinsic allows annotation of local variables with arbitrary strings.
6780 This can be useful for special purpose optimizations that want to look for
6781 these annotations. These have no other defined use, they are ignored by code
6782 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6784</div>
6785
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6786<!-- _______________________________________________________________________ -->
6787<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6788 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6789</div>
6790
6791<div class="doc_text">
6792
6793<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6794<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6795 any integer bit width.</p>
6796
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6797<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6798 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6799 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6800 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6801 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6802 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]6803</pre>
6804
6805<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6806<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6807
6808<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6809<p>The first argument is an integer value (result of some expression), the
6810 second is a pointer to a global string, the third is a pointer to a global
6811 string which is the source file name, and the last argument is the line
6812 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6813
6814<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6815<p>This intrinsic allows annotations to be put on arbitrary expressions with
6816 arbitrary strings. This can be useful for special purpose optimizations that
6817 want to look for these annotations. These have no other defined use, they
6818 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6819
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6820</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6821
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6822<!-- _______________________________________________________________________ -->
6823<div class="doc_subsubsection">
6824 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6825</div>
6826
6827<div class="doc_text">
6828
6829<h5>Syntax:</h5>
6830<pre>
6831 declare void @llvm.trap()
6832</pre>
6833
6834<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6835<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6836
6837<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6838<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6839
6840<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841<p>This intrinsics is lowered to the target dependent trap instruction. If the
6842 target does not have a trap instruction, this intrinsic will be lowered to
6843 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6844
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6845</div>
6846
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6847<!-- _______________________________________________________________________ -->
6848<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6849 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6850</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6851
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6852<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6853
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6854<h5>Syntax:</h5>
6855<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6856 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6857</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6858
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6859<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6860<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
6861 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
6862 ensure that it is placed on the stack before local variables.</p>
6863
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6864<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6865<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
6866 arguments. The first argument is the value loaded from the stack
6867 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
6868 that has enough space to hold the value of the guard.</p>
6869
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6870<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6871<p>This intrinsic causes the prologue/epilogue inserter to force the position of
6872 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6873 stack. This is to ensure that if a local variable on the stack is
6874 overwritten, it will destroy the value of the guard. When the function exits,
6875 the guard on the stack is checked against the original guard. If they're
6876 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
6877 function.</p>
6878
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6879</div>
6880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6881<!-- *********************************************************************** -->
6882<hr>
6883<address>
6884 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6885 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6886 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6887 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]6888
6889 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6890 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6891 Last modified: $Date$
6892</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6894</body>
6895</html>