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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / ece4180609c6ec2e21dfef5f27eb9bf7b65351e4 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
27 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
28 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
29 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
30 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
31 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
32 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
33 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner0fee5c22009-10-10 18:26:06 +0000[diff] [blame]34 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendlinge2753242009-07-20 02:41:50 +0000[diff] [blame]35 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
36 <li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
37 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
38 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]39 </ol>
40 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]41 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]42 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 <li><a href="#globalvars">Global Variables</a></li>
44 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]45 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]46 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]47 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]48 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
50 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]51 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]52 </ol>
53 </li>
54 <li><a href="#typesystem">Type System</a>
55 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]56 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
58 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]59 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]60 <li><a href="#t_floating">Floating Point Types</a></li>
61 <li><a href="#t_void">Void Type</a></li>
62 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]63 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]64 </ol>
65 </li>
66 <li><a href="#t_derived">Derived Types</a>
67 <ol>
68 <li><a href="#t_array">Array Type</a></li>
69 <li><a href="#t_function">Function Type</a></li>
70 <li><a href="#t_pointer">Pointer Type</a></li>
71 <li><a href="#t_struct">Structure Type</a></li>
72 <li><a href="#t_pstruct">Packed Structure Type</a></li>
73 <li><a href="#t_vector">Vector Type</a></li>
74 <li><a href="#t_opaque">Opaque Type</a></li>
75 </ol>
76 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]77 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]78 </ol>
79 </li>
80 <li><a href="#constants">Constants</a>
81 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]82 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]83 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]84 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
85 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]86 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]87 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]88 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]89 </ol>
90 </li>
91 <li><a href="#othervalues">Other Values</a>
92 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]94 </ol>
95 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]96 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
97 <ol>
98 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]99 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
100 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]101 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
102 Global Variable</a></li>
103 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
104 Global Variable</a></li>
105 </ol>
106 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]107 <li><a href="#instref">Instruction Reference</a>
108 <ol>
109 <li><a href="#terminators">Terminator Instructions</a>
110 <ol>
111 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
112 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
113 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]114 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]115 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
116 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
117 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
118 </ol>
119 </li>
120 <li><a href="#binaryops">Binary Operations</a>
121 <ol>
122 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]123 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]124 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]125 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]126 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]127 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
129 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
130 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
131 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
132 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
133 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
134 </ol>
135 </li>
136 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
137 <ol>
138 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
139 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
140 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
141 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
142 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
143 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
144 </ol>
145 </li>
146 <li><a href="#vectorops">Vector Operations</a>
147 <ol>
148 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
149 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
150 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
151 </ol>
152 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]153 <li><a href="#aggregateops">Aggregate Operations</a>
154 <ol>
155 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
156 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
157 </ol>
158 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]159 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
160 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]161 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
162 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
163 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
164 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
165 </ol>
166 </li>
167 <li><a href="#convertops">Conversion Operations</a>
168 <ol>
169 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
170 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
171 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
176 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
177 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
178 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
179 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
180 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
181 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]182 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]183 <li><a href="#otherops">Other Operations</a>
184 <ol>
185 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
186 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
187 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
188 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
189 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
190 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
191 </ol>
192 </li>
193 </ol>
194 </li>
195 <li><a href="#intrinsics">Intrinsic Functions</a>
196 <ol>
197 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
198 <ol>
199 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
200 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
202 </ol>
203 </li>
204 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
205 <ol>
206 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
207 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
209 </ol>
210 </li>
211 <li><a href="#int_codegen">Code Generator Intrinsics</a>
212 <ol>
213 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
214 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
216 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
217 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
218 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
219 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
220 </ol>
221 </li>
222 <li><a href="#int_libc">Standard C Library Intrinsics</a>
223 <ol>
224 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
225 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]229 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
230 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]232 </ol>
233 </li>
234 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
235 <ol>
236 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
237 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
238 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]240 </ol>
241 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]242 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
243 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]244 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
245 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
248 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]249 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]250 </ol>
251 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]252 <li><a href="#int_debugger">Debugger intrinsics</a></li>
253 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]254 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]255 <ol>
256 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]257 </ol>
258 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]259 <li><a href="#int_atomics">Atomic intrinsics</a>
260 <ol>
261 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
262 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
263 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
264 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
265 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
266 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
267 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
268 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
269 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
270 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
271 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
272 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
273 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
274 </ol>
275 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]276 <li><a href="#int_memorymarkers">Memory Use Markers</a>
277 <ol>
278 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
279 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
280 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
281 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
282 </ol>
283 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]284 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]285 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]286 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]287 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]288 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]289 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]290 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]291 '<tt>llvm.trap</tt>' Intrinsic</a></li>
292 <li><a href="#int_stackprotector">
293 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]294 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]295 </li>
296 </ol>
297 </li>
298</ol>
299
300<div class="doc_author">
301 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
302 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
303</div>
304
305<!-- *********************************************************************** -->
306<div class="doc_section"> <a name="abstract">Abstract </a></div>
307<!-- *********************************************************************** -->
308
309<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]310
311<p>This document is a reference manual for the LLVM assembly language. LLVM is
312 a Static Single Assignment (SSA) based representation that provides type
313 safety, low-level operations, flexibility, and the capability of representing
314 'all' high-level languages cleanly. It is the common code representation
315 used throughout all phases of the LLVM compilation strategy.</p>
316
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]317</div>
318
319<!-- *********************************************************************** -->
320<div class="doc_section"> <a name="introduction">Introduction</a> </div>
321<!-- *********************************************************************** -->
322
323<div class="doc_text">
324
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]325<p>The LLVM code representation is designed to be used in three different forms:
326 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
327 for fast loading by a Just-In-Time compiler), and as a human readable
328 assembly language representation. This allows LLVM to provide a powerful
329 intermediate representation for efficient compiler transformations and
330 analysis, while providing a natural means to debug and visualize the
331 transformations. The three different forms of LLVM are all equivalent. This
332 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]333
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]334<p>The LLVM representation aims to be light-weight and low-level while being
335 expressive, typed, and extensible at the same time. It aims to be a
336 "universal IR" of sorts, by being at a low enough level that high-level ideas
337 may be cleanly mapped to it (similar to how microprocessors are "universal
338 IR's", allowing many source languages to be mapped to them). By providing
339 type information, LLVM can be used as the target of optimizations: for
340 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]341 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]342 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
344</div>
345
346<!-- _______________________________________________________________________ -->
347<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
348
349<div class="doc_text">
350
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]351<p>It is important to note that this document describes 'well formed' LLVM
352 assembly language. There is a difference between what the parser accepts and
353 what is considered 'well formed'. For example, the following instruction is
354 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355
356<div class="doc_code">
357<pre>
358%x = <a href="#i_add">add</a> i32 1, %x
359</pre>
360</div>
361
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]362<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
363 LLVM infrastructure provides a verification pass that may be used to verify
364 that an LLVM module is well formed. This pass is automatically run by the
365 parser after parsing input assembly and by the optimizer before it outputs
366 bitcode. The violations pointed out by the verifier pass indicate bugs in
367 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]369</div>
370
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]371<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372
373<!-- *********************************************************************** -->
374<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
375<!-- *********************************************************************** -->
376
377<div class="doc_text">
378
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]379<p>LLVM identifiers come in two basic types: global and local. Global
380 identifiers (functions, global variables) begin with the <tt>'@'</tt>
381 character. Local identifiers (register names, types) begin with
382 the <tt>'%'</tt> character. Additionally, there are three different formats
383 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]384
385<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]386 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]387 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
388 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
389 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
390 other characters in their names can be surrounded with quotes. Special
391 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
392 ASCII code for the character in hexadecimal. In this way, any character
393 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]394
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]395 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]396 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]397
398 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]399 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]400</ol>
401
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]402<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]403 don't need to worry about name clashes with reserved words, and the set of
404 reserved words may be expanded in the future without penalty. Additionally,
405 unnamed identifiers allow a compiler to quickly come up with a temporary
406 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]407
408<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]409 languages. There are keywords for different opcodes
410 ('<tt><a href="#i_add">add</a></tt>',
411 '<tt><a href="#i_bitcast">bitcast</a></tt>',
412 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
413 ('<tt><a href="#t_void">void</a></tt>',
414 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
415 reserved words cannot conflict with variable names, because none of them
416 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]417
418<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]419 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]420
421<p>The easy way:</p>
422
423<div class="doc_code">
424<pre>
425%result = <a href="#i_mul">mul</a> i32 %X, 8
426</pre>
427</div>
428
429<p>After strength reduction:</p>
430
431<div class="doc_code">
432<pre>
433%result = <a href="#i_shl">shl</a> i32 %X, i8 3
434</pre>
435</div>
436
437<p>And the hard way:</p>
438
439<div class="doc_code">
440<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]441%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
442%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]443%result = <a href="#i_add">add</a> i32 %1, %1
444</pre>
445</div>
446
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]447<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
448 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]449
450<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]451 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]452 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453
454 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]455 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456
457 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458</ol>
459
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]460<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]461 demonstrating instructions, we will follow an instruction with a comment that
462 defines the type and name of value produced. Comments are shown in italic
463 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]464
465</div>
466
467<!-- *********************************************************************** -->
468<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
469<!-- *********************************************************************** -->
470
471<!-- ======================================================================= -->
472<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
473</div>
474
475<div class="doc_text">
476
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]477<p>LLVM programs are composed of "Module"s, each of which is a translation unit
478 of the input programs. Each module consists of functions, global variables,
479 and symbol table entries. Modules may be combined together with the LLVM
480 linker, which merges function (and global variable) definitions, resolves
481 forward declarations, and merges symbol table entries. Here is an example of
482 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]483
484<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]485<pre>
486<i>; Declare the string constant as a global constant.</i>
487<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]488
489<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]490<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]491
492<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]493define i32 @main() { <i>; i32()* </i>
494 <i>; Convert [13 x i8]* to i8 *...</i>
495 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]496
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]497 <i>; Call puts function to write out the string to stdout.</i>
498 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
499 <a href="#i_ret">ret</a> i32 0<br>}<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]500</pre>
501</div>
502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]503<p>This example is made up of a <a href="#globalvars">global variable</a> named
504 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
505 a <a href="#functionstructure">function definition</a> for
506 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]508<p>In general, a module is made up of a list of global values, where both
509 functions and global variables are global values. Global values are
510 represented by a pointer to a memory location (in this case, a pointer to an
511 array of char, and a pointer to a function), and have one of the
512 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]513
514</div>
515
516<!-- ======================================================================= -->
517<div class="doc_subsection">
518 <a name="linkage">Linkage Types</a>
519</div>
520
521<div class="doc_text">
522
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]523<p>All Global Variables and Functions have one of the following types of
524 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]525
526<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]527 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]528 <dd>Global values with private linkage are only directly accessible by objects
529 in the current module. In particular, linking code into a module with an
530 private global value may cause the private to be renamed as necessary to
531 avoid collisions. Because the symbol is private to the module, all
532 references can be updated. This doesn't show up in any symbol table in the
533 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]534
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]535 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]536 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]537 removed by the linker after evaluation. Note that (unlike private
538 symbols) linker_private symbols are subject to coalescing by the linker:
539 weak symbols get merged and redefinitions are rejected. However, unlike
540 normal strong symbols, they are removed by the linker from the final
541 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]542
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]544 <dd>Similar to private, but the value shows as a local symbol
545 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
546 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]547
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]548 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]549 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]550 into the object file corresponding to the LLVM module. They exist to
551 allow inlining and other optimizations to take place given knowledge of
552 the definition of the global, which is known to be somewhere outside the
553 module. Globals with <tt>available_externally</tt> linkage are allowed to
554 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
555 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]556
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]557 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]558 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]559 the same name when linkage occurs. This is typically used to implement
560 inline functions, templates, or other code which must be generated in each
561 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
562 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]563
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]564 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]565 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
566 <tt>linkonce</tt> linkage, except that unreferenced globals with
567 <tt>weak</tt> linkage may not be discarded. This is used for globals that
568 are declared "weak" in C source code.</dd>
569
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]571 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
572 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
573 global scope.
574 Symbols with "<tt>common</tt>" linkage are merged in the same way as
575 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]576 <tt>common</tt> symbols may not have an explicit section,
577 must have a zero initializer, and may not be marked '<a
578 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
579 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]581
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]582 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]584 pointer to array type. When two global variables with appending linkage
585 are linked together, the two global arrays are appended together. This is
586 the LLVM, typesafe, equivalent of having the system linker append together
587 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]590 <dd>The semantics of this linkage follow the ELF object file model: the symbol
591 is weak until linked, if not linked, the symbol becomes null instead of
592 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]593
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]594 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
595 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]596 <dd>Some languages allow differing globals to be merged, such as two functions
597 with different semantics. Other languages, such as <tt>C++</tt>, ensure
598 that only equivalent globals are ever merged (the "one definition rule" -
599 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
600 and <tt>weak_odr</tt> linkage types to indicate that the global will only
601 be merged with equivalent globals. These linkage types are otherwise the
602 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]605 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]606 visible, meaning that it participates in linkage and can be used to
607 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608</dl>
609
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]610<p>The next two types of linkage are targeted for Microsoft Windows platform
611 only. They are designed to support importing (exporting) symbols from (to)
612 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]614<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]615 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]617 or variable via a global pointer to a pointer that is set up by the DLL
618 exporting the symbol. On Microsoft Windows targets, the pointer name is
619 formed by combining <code>__imp_</code> and the function or variable
620 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]621
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]622 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]624 pointer to a pointer in a DLL, so that it can be referenced with the
625 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
626 name is formed by combining <code>__imp_</code> and the function or
627 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628</dl>
629
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]630<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
631 another module defined a "<tt>.LC0</tt>" variable and was linked with this
632 one, one of the two would be renamed, preventing a collision. Since
633 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
634 declarations), they are accessible outside of the current module.</p>
635
636<p>It is illegal for a function <i>declaration</i> to have any linkage type
637 other than "externally visible", <tt>dllimport</tt>
638 or <tt>extern_weak</tt>.</p>
639
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]640<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]641 or <tt>weak_odr</tt> linkages.</p>
642
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]643</div>
644
645<!-- ======================================================================= -->
646<div class="doc_subsection">
647 <a name="callingconv">Calling Conventions</a>
648</div>
649
650<div class="doc_text">
651
652<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]653 and <a href="#i_invoke">invokes</a> can all have an optional calling
654 convention specified for the call. The calling convention of any pair of
655 dynamic caller/callee must match, or the behavior of the program is
656 undefined. The following calling conventions are supported by LLVM, and more
657 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658
659<dl>
660 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]661 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]662 specified) matches the target C calling conventions. This calling
663 convention supports varargs function calls and tolerates some mismatch in
664 the declared prototype and implemented declaration of the function (as
665 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]666
667 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]668 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]669 (e.g. by passing things in registers). This calling convention allows the
670 target to use whatever tricks it wants to produce fast code for the
671 target, without having to conform to an externally specified ABI
672 (Application Binary Interface). Implementations of this convention should
673 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
674 optimization</a> to be supported. This calling convention does not
675 support varargs and requires the prototype of all callees to exactly match
676 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]677
678 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]679 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]680 as possible under the assumption that the call is not commonly executed.
681 As such, these calls often preserve all registers so that the call does
682 not break any live ranges in the caller side. This calling convention
683 does not support varargs and requires the prototype of all callees to
684 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]685
686 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]687 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]688 target-specific calling conventions to be used. Target specific calling
689 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]690</dl>
691
692<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]693 support Pascal conventions or any other well-known target-independent
694 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]695
696</div>
697
698<!-- ======================================================================= -->
699<div class="doc_subsection">
700 <a name="visibility">Visibility Styles</a>
701</div>
702
703<div class="doc_text">
704
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]705<p>All Global Variables and Functions have one of the following visibility
706 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]707
708<dl>
709 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]710 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]711 that the declaration is visible to other modules and, in shared libraries,
712 means that the declared entity may be overridden. On Darwin, default
713 visibility means that the declaration is visible to other modules. Default
714 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]715
716 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]718 object if they are in the same shared object. Usually, hidden visibility
719 indicates that the symbol will not be placed into the dynamic symbol
720 table, so no other module (executable or shared library) can reference it
721 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]722
723 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]725 the dynamic symbol table, but that references within the defining module
726 will bind to the local symbol. That is, the symbol cannot be overridden by
727 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]728</dl>
729
730</div>
731
732<!-- ======================================================================= -->
733<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]734 <a name="namedtypes">Named Types</a>
735</div>
736
737<div class="doc_text">
738
739<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]740 it easier to read the IR and make the IR more condensed (particularly when
741 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]742
743<div class="doc_code">
744<pre>
745%mytype = type { %mytype*, i32 }
746</pre>
747</div>
748
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]749<p>You may give a name to any <a href="#typesystem">type</a> except
750 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
751 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]752
753<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]754 and that you can therefore specify multiple names for the same type. This
755 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
756 uses structural typing, the name is not part of the type. When printing out
757 LLVM IR, the printer will pick <em>one name</em> to render all types of a
758 particular shape. This means that if you have code where two different
759 source types end up having the same LLVM type, that the dumper will sometimes
760 print the "wrong" or unexpected type. This is an important design point and
761 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]762
763</div>
764
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]765<!-- ======================================================================= -->
766<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]767 <a name="globalvars">Global Variables</a>
768</div>
769
770<div class="doc_text">
771
772<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]773 instead of run-time. Global variables may optionally be initialized, may
774 have an explicit section to be placed in, and may have an optional explicit
775 alignment specified. A variable may be defined as "thread_local", which
776 means that it will not be shared by threads (each thread will have a
777 separated copy of the variable). A variable may be defined as a global
778 "constant," which indicates that the contents of the variable
779 will <b>never</b> be modified (enabling better optimization, allowing the
780 global data to be placed in the read-only section of an executable, etc).
781 Note that variables that need runtime initialization cannot be marked
782 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]783
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]784<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
785 constant, even if the final definition of the global is not. This capability
786 can be used to enable slightly better optimization of the program, but
787 requires the language definition to guarantee that optimizations based on the
788 'constantness' are valid for the translation units that do not include the
789 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]790
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]791<p>As SSA values, global variables define pointer values that are in scope
792 (i.e. they dominate) all basic blocks in the program. Global variables
793 always define a pointer to their "content" type because they describe a
794 region of memory, and all memory objects in LLVM are accessed through
795 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]796
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]797<p>A global variable may be declared to reside in a target-specific numbered
798 address space. For targets that support them, address spaces may affect how
799 optimizations are performed and/or what target instructions are used to
800 access the variable. The default address space is zero. The address space
801 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]804 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]805
806<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]807 the alignment is set to zero, the alignment of the global is set by the
808 target to whatever it feels convenient. If an explicit alignment is
809 specified, the global is forced to have at least that much alignment. All
810 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]812<p>For example, the following defines a global in a numbered address space with
813 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814
815<div class="doc_code">
816<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]817@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]818</pre>
819</div>
820
821</div>
822
823
824<!-- ======================================================================= -->
825<div class="doc_subsection">
826 <a name="functionstructure">Functions</a>
827</div>
828
829<div class="doc_text">
830
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]831<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
832 optional <a href="#linkage">linkage type</a>, an optional
833 <a href="#visibility">visibility style</a>, an optional
834 <a href="#callingconv">calling convention</a>, a return type, an optional
835 <a href="#paramattrs">parameter attribute</a> for the return type, a function
836 name, a (possibly empty) argument list (each with optional
837 <a href="#paramattrs">parameter attributes</a>), optional
838 <a href="#fnattrs">function attributes</a>, an optional section, an optional
839 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
840 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]841
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]842<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
843 optional <a href="#linkage">linkage type</a>, an optional
844 <a href="#visibility">visibility style</a>, an optional
845 <a href="#callingconv">calling convention</a>, a return type, an optional
846 <a href="#paramattrs">parameter attribute</a> for the return type, a function
847 name, a possibly empty list of arguments, an optional alignment, and an
848 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]849
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]850<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]851 (Control Flow Graph) for the function. Each basic block may optionally start
852 with a label (giving the basic block a symbol table entry), contains a list
853 of instructions, and ends with a <a href="#terminators">terminator</a>
854 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]855
856<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]857 executed on entrance to the function, and it is not allowed to have
858 predecessor basic blocks (i.e. there can not be any branches to the entry
859 block of a function). Because the block can have no predecessors, it also
860 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]861
862<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]863 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864
865<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]866 the alignment is set to zero, the alignment of the function is set by the
867 target to whatever it feels convenient. If an explicit alignment is
868 specified, the function is forced to have at least that much alignment. All
869 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]870
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]871<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]872<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]873<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]874define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]875 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
876 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
877 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
878 [<a href="#gc">gc</a>] { ... }
879</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]880</div>
881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]882</div>
883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884<!-- ======================================================================= -->
885<div class="doc_subsection">
886 <a name="aliasstructure">Aliases</a>
887</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]889<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]890
891<p>Aliases act as "second name" for the aliasee value (which can be either
892 function, global variable, another alias or bitcast of global value). Aliases
893 may have an optional <a href="#linkage">linkage type</a>, and an
894 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]896<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]897<div class="doc_code">
898<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]899@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900</pre>
901</div>
902
903</div>
904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]905<!-- ======================================================================= -->
906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]908<div class="doc_text">
909
910<p>The return type and each parameter of a function type may have a set of
911 <i>parameter attributes</i> associated with them. Parameter attributes are
912 used to communicate additional information about the result or parameters of
913 a function. Parameter attributes are considered to be part of the function,
914 not of the function type, so functions with different parameter attributes
915 can have the same function type.</p>
916
917<p>Parameter attributes are simple keywords that follow the type specified. If
918 multiple parameter attributes are needed, they are space separated. For
919 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]920
921<div class="doc_code">
922<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]923declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]924declare i32 @atoi(i8 zeroext)
925declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]926</pre>
927</div>
928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]929<p>Note that any attributes for the function result (<tt>nounwind</tt>,
930 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]931
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]932<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]934<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]935 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936 <dd>This indicates to the code generator that the parameter or return value
937 should be zero-extended to a 32-bit value by the caller (for a parameter)
938 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]939
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]940 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]941 <dd>This indicates to the code generator that the parameter or return value
942 should be sign-extended to a 32-bit value by the caller (for a parameter)
943 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]944
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]945 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]946 <dd>This indicates that this parameter or return value should be treated in a
947 special target-dependent fashion during while emitting code for a function
948 call or return (usually, by putting it in a register as opposed to memory,
949 though some targets use it to distinguish between two different kinds of
950 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]951
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]952 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]953 <dd>This indicates that the pointer parameter should really be passed by value
954 to the function. The attribute implies that a hidden copy of the pointee
955 is made between the caller and the callee, so the callee is unable to
956 modify the value in the callee. This attribute is only valid on LLVM
957 pointer arguments. It is generally used to pass structs and arrays by
958 value, but is also valid on pointers to scalars. The copy is considered
959 to belong to the caller not the callee (for example,
960 <tt><a href="#readonly">readonly</a></tt> functions should not write to
961 <tt>byval</tt> parameters). This is not a valid attribute for return
962 values. The byval attribute also supports specifying an alignment with
963 the align attribute. This has a target-specific effect on the code
964 generator that usually indicates a desired alignment for the synthesized
965 stack slot.</dd>
966
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]967 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]968 <dd>This indicates that the pointer parameter specifies the address of a
969 structure that is the return value of the function in the source program.
970 This pointer must be guaranteed by the caller to be valid: loads and
971 stores to the structure may be assumed by the callee to not to trap. This
972 may only be applied to the first parameter. This is not a valid attribute
973 for return values. </dd>
974
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]975 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]976 <dd>This indicates that the pointer does not alias any global or any other
977 parameter. The caller is responsible for ensuring that this is the
978 case. On a function return value, <tt>noalias</tt> additionally indicates
979 that the pointer does not alias any other pointers visible to the
980 caller. For further details, please see the discussion of the NoAlias
981 response in
982 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
983 analysis</a>.</dd>
984
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]985 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]986 <dd>This indicates that the callee does not make any copies of the pointer
987 that outlive the callee itself. This is not a valid attribute for return
988 values.</dd>
989
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]990 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]991 <dd>This indicates that the pointer parameter can be excised using the
992 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
993 attribute for return values.</dd>
994</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]995
996</div>
997
998<!-- ======================================================================= -->
999<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1000 <a name="gc">Garbage Collector Names</a>
1001</div>
1002
1003<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1004
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1005<p>Each function may specify a garbage collector name, which is simply a
1006 string:</p>
1007
1008<div class="doc_code">
1009<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1010define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1011</pre>
1012</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1013
1014<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1015 collector which will cause the compiler to alter its output in order to
1016 support the named garbage collection algorithm.</p>
1017
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1018</div>
1019
1020<!-- ======================================================================= -->
1021<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1022 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1023</div>
1024
1025<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1026
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1027<p>Function attributes are set to communicate additional information about a
1028 function. Function attributes are considered to be part of the function, not
1029 of the function type, so functions with different parameter attributes can
1030 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1031
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1032<p>Function attributes are simple keywords that follow the type specified. If
1033 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1034
1035<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1036<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1037define void @f() noinline { ... }
1038define void @f() alwaysinline { ... }
1039define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1040define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1041</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1042</div>
1043
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1044<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1045 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1046 <dd>This attribute indicates that the inliner should attempt to inline this
1047 function into callers whenever possible, ignoring any active inlining size
1048 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1049
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1050 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1051 <dd>This attribute indicates that the source code contained a hint that inlining
1052 this function is desirable (such as the "inline" keyword in C/C++). It
1053 is just a hint; it imposes no requirements on the inliner.</dd>
1054
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1055 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1056 <dd>This attribute indicates that the inliner should never inline this
1057 function in any situation. This attribute may not be used together with
1058 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1059
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1060 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1061 <dd>This attribute suggests that optimization passes and code generator passes
1062 make choices that keep the code size of this function low, and otherwise
1063 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1064
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1065 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1066 <dd>This function attribute indicates that the function never returns
1067 normally. This produces undefined behavior at runtime if the function
1068 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1069
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1070 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1071 <dd>This function attribute indicates that the function never returns with an
1072 unwind or exceptional control flow. If the function does unwind, its
1073 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1074
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1075 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1076 <dd>This attribute indicates that the function computes its result (or decides
1077 to unwind an exception) based strictly on its arguments, without
1078 dereferencing any pointer arguments or otherwise accessing any mutable
1079 state (e.g. memory, control registers, etc) visible to caller functions.
1080 It does not write through any pointer arguments
1081 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1082 changes any state visible to callers. This means that it cannot unwind
1083 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1084 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1085
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1086 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1087 <dd>This attribute indicates that the function does not write through any
1088 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1089 arguments) or otherwise modify any state (e.g. memory, control registers,
1090 etc) visible to caller functions. It may dereference pointer arguments
1091 and read state that may be set in the caller. A readonly function always
1092 returns the same value (or unwinds an exception identically) when called
1093 with the same set of arguments and global state. It cannot unwind an
1094 exception by calling the <tt>C++</tt> exception throwing methods, but may
1095 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1096
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1097 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1098 <dd>This attribute indicates that the function should emit a stack smashing
1099 protector. It is in the form of a "canary"&mdash;a random value placed on
1100 the stack before the local variables that's checked upon return from the
1101 function to see if it has been overwritten. A heuristic is used to
1102 determine if a function needs stack protectors or not.<br>
1103<br>
1104 If a function that has an <tt>ssp</tt> attribute is inlined into a
1105 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1106 function will have an <tt>ssp</tt> attribute.</dd>
1107
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1108 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1109 <dd>This attribute indicates that the function should <em>always</em> emit a
1110 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1111 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1112<br>
1113 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1114 function that doesn't have an <tt>sspreq</tt> attribute or which has
1115 an <tt>ssp</tt> attribute, then the resulting function will have
1116 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1117
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1118 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119 <dd>This attribute indicates that the code generator should not use a red
1120 zone, even if the target-specific ABI normally permits it.</dd>
1121
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1122 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1123 <dd>This attributes disables implicit floating point instructions.</dd>
1124
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1125 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1126 <dd>This attribute disables prologue / epilogue emission for the function.
1127 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1128</dl>
1129
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1130</div>
1131
1132<!-- ======================================================================= -->
1133<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1134 <a name="moduleasm">Module-Level Inline Assembly</a>
1135</div>
1136
1137<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1138
1139<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1140 the GCC "file scope inline asm" blocks. These blocks are internally
1141 concatenated by LLVM and treated as a single unit, but may be separated in
1142 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1143
1144<div class="doc_code">
1145<pre>
1146module asm "inline asm code goes here"
1147module asm "more can go here"
1148</pre>
1149</div>
1150
1151<p>The strings can contain any character by escaping non-printable characters.
1152 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]1153 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1154
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1155<p>The inline asm code is simply printed to the machine code .s file when
1156 assembly code is generated.</p>
1157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158</div>
1159
1160<!-- ======================================================================= -->
1161<div class="doc_subsection">
1162 <a name="datalayout">Data Layout</a>
1163</div>
1164
1165<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1166
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1167<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1168 data is to be laid out in memory. The syntax for the data layout is
1169 simply:</p>
1170
1171<div class="doc_code">
1172<pre>
1173target datalayout = "<i>layout specification</i>"
1174</pre>
1175</div>
1176
1177<p>The <i>layout specification</i> consists of a list of specifications
1178 separated by the minus sign character ('-'). Each specification starts with
1179 a letter and may include other information after the letter to define some
1180 aspect of the data layout. The specifications accepted are as follows:</p>
1181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1182<dl>
1183 <dt><tt>E</tt></dt>
1184 <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]1185 bits with the most significance have the lowest address location.</dd>
1186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1187 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1188 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1189 the bits with the least significance have the lowest address
1190 location.</dd>
1191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1192 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1193 <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]1194 <i>preferred</i> alignments. All sizes are in bits. Specifying
1195 the <i>pref</i> alignment is optional. If omitted, the
1196 preceding <tt>:</tt> should be omitted too.</dd>
1197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1198 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1199 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1200 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1202 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1203 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1204 <i>size</i>.</dd>
1205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1207 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1208 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1209 (double).</dd>
1210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1211 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1212 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1213 <i>size</i>.</dd>
1214
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1215 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1216 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1217 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame^]1218
1219 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1220 <dd>This specifies a set of native integer widths for the target CPU
1221 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1222 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
1223 this set are considered to support most general arithmetic
1224 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1225</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1228 default set of specifications which are then (possibly) overriden by the
1229 specifications in the <tt>datalayout</tt> keyword. The default specifications
1230 are given in this list:</p>
1231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1232<ul>
1233 <li><tt>E</tt> - big endian</li>
1234 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1235 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1236 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1237 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1238 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1239 <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]1240 alignment of 64-bits</li>
1241 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1242 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1243 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1244 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1245 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1246 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1247</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1248
1249<p>When LLVM is determining the alignment for a given type, it uses the
1250 following rules:</p>
1251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252<ol>
1253 <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]1254 specification is used.</li>
1255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1256 <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]1257 smallest integer type that is larger than the bitwidth of the sought type
1258 is used. If none of the specifications are larger than the bitwidth then
1259 the the largest integer type is used. For example, given the default
1260 specifications above, the i7 type will use the alignment of i8 (next
1261 largest) while both i65 and i256 will use the alignment of i64 (largest
1262 specified).</li>
1263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264 <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]1265 largest vector type that is smaller than the sought vector type will be
1266 used as a fall back. This happens because &lt;128 x double&gt; can be
1267 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1268</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1270</div>
1271
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1272<!-- ======================================================================= -->
1273<div class="doc_subsection">
1274 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1275</div>
1276
1277<div class="doc_text">
1278
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1279<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1280with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1281is undefined. Pointer values are associated with address ranges
1282according to the following rules:</p>
1283
1284<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1285 <li>A pointer value formed from a
1286 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1287 is associated with the addresses associated with the first operand
1288 of the <tt>getelementptr</tt>.</li>
1289 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1290 range of the variable's storage.</li>
1291 <li>The result value of an allocation instruction is associated with
1292 the address range of the allocated storage.</li>
1293 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1294 no address.</li>
1295 <li>A pointer value formed by an
1296 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1297 address ranges of all pointer values that contribute (directly or
1298 indirectly) to the computation of the pointer's value.</li>
1299 <li>The result value of a
1300 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1301 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1302 <li>An integer constant other than zero or a pointer value returned
1303 from a function not defined within LLVM may be associated with address
1304 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1305 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1306 allocated by mechanisms provided by LLVM.</li>
1307 </ul>
1308
1309<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1310<tt><a href="#i_load">load</a></tt> merely indicates the size and
1311alignment of the memory from which to load, as well as the
1312interpretation of the value. The first operand of a
1313<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1314and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1315
1316<p>Consequently, type-based alias analysis, aka TBAA, aka
1317<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1318LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1319additional information which specialized optimization passes may use
1320to implement type-based alias analysis.</p>
1321
1322</div>
1323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1324<!-- *********************************************************************** -->
1325<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1326<!-- *********************************************************************** -->
1327
1328<div class="doc_text">
1329
1330<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1331 intermediate representation. Being typed enables a number of optimizations
1332 to be performed on the intermediate representation directly, without having
1333 to do extra analyses on the side before the transformation. A strong type
1334 system makes it easier to read the generated code and enables novel analyses
1335 and transformations that are not feasible to perform on normal three address
1336 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337
1338</div>
1339
1340<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1341<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1342Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1345
1346<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1347
1348<table border="1" cellspacing="0" cellpadding="4">
1349 <tbody>
1350 <tr><th>Classification</th><th>Types</th></tr>
1351 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1352 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1353 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1354 </tr>
1355 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1356 <td><a href="#t_floating">floating point</a></td>
1357 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1358 </tr>
1359 <tr>
1360 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1361 <td><a href="#t_integer">integer</a>,
1362 <a href="#t_floating">floating point</a>,
1363 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1364 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1365 <a href="#t_struct">structure</a>,
1366 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1367 <a href="#t_label">label</a>,
1368 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1369 </td>
1370 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1371 <tr>
1372 <td><a href="#t_primitive">primitive</a></td>
1373 <td><a href="#t_label">label</a>,
1374 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1375 <a href="#t_floating">floating point</a>,
1376 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1377 </tr>
1378 <tr>
1379 <td><a href="#t_derived">derived</a></td>
1380 <td><a href="#t_integer">integer</a>,
1381 <a href="#t_array">array</a>,
1382 <a href="#t_function">function</a>,
1383 <a href="#t_pointer">pointer</a>,
1384 <a href="#t_struct">structure</a>,
1385 <a href="#t_pstruct">packed structure</a>,
1386 <a href="#t_vector">vector</a>,
1387 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1388 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1389 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1390 </tbody>
1391</table>
1392
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1393<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1394 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1395 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1397</div>
1398
1399<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1400<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1401
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1402<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1403
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1404<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1405 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1406
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1407</div>
1408
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1409<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]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 type that simply specifies an arbitrary
1416 bit width for the integer type desired. Any bit width from 1 bit to
1417 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1418
1419<h5>Syntax:</h5>
1420<pre>
1421 iN
1422</pre>
1423
1424<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1425 value.</p>
1426
1427<h5>Examples:</h5>
1428<table class="layout">
1429 <tr class="layout">
1430 <td class="left"><tt>i1</tt></td>
1431 <td class="left">a single-bit integer.</td>
1432 </tr>
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>
1441</table>
1442
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>
1447
1448</div>
1449
1450<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1451<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1452
1453<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1454
1455<table>
1456 <tbody>
1457 <tr><th>Type</th><th>Description</th></tr>
1458 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1459 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1460 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1461 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1462 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1463 </tbody>
1464</table>
1465
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1466</div>
1467
1468<!-- _______________________________________________________________________ -->
1469<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1470
1471<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1472
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1473<h5>Overview:</h5>
1474<p>The void type does not represent any value and has no size.</p>
1475
1476<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1477<pre>
1478 void
1479</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1480
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1481</div>
1482
1483<!-- _______________________________________________________________________ -->
1484<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1485
1486<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1487
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1488<h5>Overview:</h5>
1489<p>The label type represents code labels.</p>
1490
1491<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1492<pre>
1493 label
1494</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1495
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1496</div>
1497
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1498<!-- _______________________________________________________________________ -->
1499<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1500
1501<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1502
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1503<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1504<p>The metadata type represents embedded metadata. No derived types may be
1505 created from metadata except for <a href="#t_function">function</a>
1506 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1507
1508<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1509<pre>
1510 metadata
1511</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1512
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1513</div>
1514
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1515
1516<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1517<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1518
1519<div class="doc_text">
1520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1521<p>The real power in LLVM comes from the derived types in the system. This is
1522 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1523 useful types. Each of these types contain one or more element types which
1524 may be a primitive type, or another derived type. For example, it is
1525 possible to have a two dimensional array, using an array as the element type
1526 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1528</div>
1529
1530<!-- _______________________________________________________________________ -->
1531<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1532
1533<div class="doc_text">
1534
1535<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1536<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1537 sequentially in memory. The array type requires a size (number of elements)
1538 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1539
1540<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1541<pre>
1542 [&lt;# elements&gt; x &lt;elementtype&gt;]
1543</pre>
1544
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1545<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1546 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547
1548<h5>Examples:</h5>
1549<table class="layout">
1550 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1551 <td class="left"><tt>[40 x i32]</tt></td>
1552 <td class="left">Array of 40 32-bit integer values.</td>
1553 </tr>
1554 <tr class="layout">
1555 <td class="left"><tt>[41 x i32]</tt></td>
1556 <td class="left">Array of 41 32-bit integer values.</td>
1557 </tr>
1558 <tr class="layout">
1559 <td class="left"><tt>[4 x i8]</tt></td>
1560 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1561 </tr>
1562</table>
1563<p>Here are some examples of multidimensional arrays:</p>
1564<table class="layout">
1565 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1566 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1567 <td class="left">3x4 array of 32-bit integer values.</td>
1568 </tr>
1569 <tr class="layout">
1570 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1571 <td class="left">12x10 array of single precision floating point values.</td>
1572 </tr>
1573 <tr class="layout">
1574 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1575 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1576 </tr>
1577</table>
1578
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1579<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1580 length array. Normally, accesses past the end of an array are undefined in
1581 LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
1582 a special case, however, zero length arrays are recognized to be variable
1583 length. This allows implementation of 'pascal style arrays' with the LLVM
1584 type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1585
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1586<p>Note that the code generator does not yet support large aggregate types to be
1587 used as function return types. The specific limit on how large an aggregate
1588 return type the code generator can currently handle is target-dependent, and
1589 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1591</div>
1592
1593<!-- _______________________________________________________________________ -->
1594<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1596<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1598<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1599<p>The function type can be thought of as a function signature. It consists of
1600 a return type and a list of formal parameter types. The return type of a
1601 function type is a scalar type, a void type, or a struct type. If the return
1602 type is a struct type then all struct elements must be of first class types,
1603 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1605<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1606<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1607 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1608</pre>
1609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1610<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]1611 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1612 which indicates that the function takes a variable number of arguments.
1613 Variable argument functions can access their arguments with
1614 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1615 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1616 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1618<h5>Examples:</h5>
1619<table class="layout">
1620 <tr class="layout">
1621 <td class="left"><tt>i32 (i32)</tt></td>
1622 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1623 </td>
1624 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1625 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1626 </tt></td>
1627 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1628 an <tt>i16</tt> that should be sign extended and a
1629 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1630 <tt>float</tt>.
1631 </td>
1632 </tr><tr class="layout">
1633 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1634 <td class="left">A vararg function that takes at least one
1635 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1636 which returns an integer. This is the signature for <tt>printf</tt> in
1637 LLVM.
1638 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1639 </tr><tr class="layout">
1640 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1641 <td class="left">A function taking an <tt>i32</tt>, returning a
1642 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1643 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644 </tr>
1645</table>
1646
1647</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1648
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649<!-- _______________________________________________________________________ -->
1650<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1652<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1654<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1655<p>The structure type is used to represent a collection of data members together
1656 in memory. The packing of the field types is defined to match the ABI of the
1657 underlying processor. The elements of a structure may be any type that has a
1658 size.</p>
1659
1660<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1661 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1662 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1664<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1665<pre>
1666 { &lt;type list&gt; }
1667</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1669<h5>Examples:</h5>
1670<table class="layout">
1671 <tr class="layout">
1672 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1673 <td class="left">A triple of three <tt>i32</tt> values</td>
1674 </tr><tr class="layout">
1675 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1676 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1677 second element is a <a href="#t_pointer">pointer</a> to a
1678 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1679 an <tt>i32</tt>.</td>
1680 </tr>
1681</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1682
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1683<p>Note that the code generator does not yet support large aggregate types to be
1684 used as function return types. The specific limit on how large an aggregate
1685 return type the code generator can currently handle is target-dependent, and
1686 also dependent on the aggregate element types.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1688</div>
1689
1690<!-- _______________________________________________________________________ -->
1691<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1692</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1693
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1694<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1696<h5>Overview:</h5>
1697<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1698 together in memory. There is no padding between fields. Further, the
1699 alignment of a packed structure is 1 byte. The elements of a packed
1700 structure may be any type that has a size.</p>
1701
1702<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1703 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1704 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1706<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1707<pre>
1708 &lt; { &lt;type list&gt; } &gt;
1709</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1711<h5>Examples:</h5>
1712<table class="layout">
1713 <tr class="layout">
1714 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1715 <td class="left">A triple of three <tt>i32</tt> values</td>
1716 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1717 <td class="left">
1718<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1719 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1720 second element is a <a href="#t_pointer">pointer</a> to a
1721 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1722 an <tt>i32</tt>.</td>
1723 </tr>
1724</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1726</div>
1727
1728<!-- _______________________________________________________________________ -->
1729<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1730
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1731<div class="doc_text">
1732
1733<h5>Overview:</h5>
1734<p>As in many languages, the pointer type represents a pointer or reference to
1735 another object, which must live in memory. Pointer types may have an optional
1736 address space attribute defining the target-specific numbered address space
1737 where the pointed-to object resides. The default address space is zero.</p>
1738
1739<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1740 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1742<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1743<pre>
1744 &lt;type&gt; *
1745</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1747<h5>Examples:</h5>
1748<table class="layout">
1749 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1750 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1751 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1752 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1753 </tr>
1754 <tr class="layout">
1755 <td class="left"><tt>i32 (i32 *) *</tt></td>
1756 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1757 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1758 <tt>i32</tt>.</td>
1759 </tr>
1760 <tr class="layout">
1761 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1762 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1763 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1764 </tr>
1765</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767</div>
1768
1769<!-- _______________________________________________________________________ -->
1770<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1771
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1772<div class="doc_text">
1773
1774<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1775<p>A vector type is a simple derived type that represents a vector of elements.
1776 Vector types are used when multiple primitive data are operated in parallel
1777 using a single instruction (SIMD). A vector type requires a size (number of
1778 elements) and an underlying primitive data type. Vectors must have a power
1779 of two length (1, 2, 4, 8, 16 ...). Vector types are considered
1780 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1781
1782<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1783<pre>
1784 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1785</pre>
1786
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1787<p>The number of elements is a constant integer value; elementtype may be any
1788 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1789
1790<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1791<table class="layout">
1792 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1793 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1794 <td class="left">Vector of 4 32-bit integer values.</td>
1795 </tr>
1796 <tr class="layout">
1797 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1798 <td class="left">Vector of 8 32-bit floating-point values.</td>
1799 </tr>
1800 <tr class="layout">
1801 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1802 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1803 </tr>
1804</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1805
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1806<p>Note that the code generator does not yet support large vector types to be
1807 used as function return types. The specific limit on how large a vector
1808 return type codegen can currently handle is target-dependent; currently it's
1809 often a few times longer than a hardware vector register.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1811</div>
1812
1813<!-- _______________________________________________________________________ -->
1814<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1815<div class="doc_text">
1816
1817<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1818<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1819 corresponds (for example) to the C notion of a forward declared structure
1820 type. In LLVM, opaque types can eventually be resolved to any type (not just
1821 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1822
1823<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1824<pre>
1825 opaque
1826</pre>
1827
1828<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1829<table class="layout">
1830 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1831 <td class="left"><tt>opaque</tt></td>
1832 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1833 </tr>
1834</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1836</div>
1837
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1838<!-- ======================================================================= -->
1839<div class="doc_subsection">
1840 <a name="t_uprefs">Type Up-references</a>
1841</div>
1842
1843<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1844
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1845<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1846<p>An "up reference" allows you to refer to a lexically enclosing type without
1847 requiring it to have a name. For instance, a structure declaration may
1848 contain a pointer to any of the types it is lexically a member of. Example
1849 of up references (with their equivalent as named type declarations)
1850 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1851
1852<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1853 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1854 { \2 }* %y = type { %y }*
1855 \1* %z = type %z*
1856</pre>
1857
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1858<p>An up reference is needed by the asmprinter for printing out cyclic types
1859 when there is no declared name for a type in the cycle. Because the
1860 asmprinter does not want to print out an infinite type string, it needs a
1861 syntax to handle recursive types that have no names (all names are optional
1862 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1863
1864<h5>Syntax:</h5>
1865<pre>
1866 \&lt;level&gt;
1867</pre>
1868
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1869<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]1870
1871<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1872<table class="layout">
1873 <tr class="layout">
1874 <td class="left"><tt>\1*</tt></td>
1875 <td class="left">Self-referential pointer.</td>
1876 </tr>
1877 <tr class="layout">
1878 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1879 <td class="left">Recursive structure where the upref refers to the out-most
1880 structure.</td>
1881 </tr>
1882</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1883
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1884</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1885
1886<!-- *********************************************************************** -->
1887<div class="doc_section"> <a name="constants">Constants</a> </div>
1888<!-- *********************************************************************** -->
1889
1890<div class="doc_text">
1891
1892<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1893 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1894
1895</div>
1896
1897<!-- ======================================================================= -->
1898<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1899
1900<div class="doc_text">
1901
1902<dl>
1903 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1904 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1905 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1906
1907 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1908 <dd>Standard integers (such as '4') are constants of
1909 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1910 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1911
1912 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1913 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1914 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1915 notation (see below). The assembler requires the exact decimal value of a
1916 floating-point constant. For example, the assembler accepts 1.25 but
1917 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1918 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1919
1920 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1921 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1922 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1923</dl>
1924
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1925<p>The one non-intuitive notation for constants is the hexadecimal form of
1926 floating point constants. For example, the form '<tt>double
1927 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1928 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1929 constants are required (and the only time that they are generated by the
1930 disassembler) is when a floating point constant must be emitted but it cannot
1931 be represented as a decimal floating point number in a reasonable number of
1932 digits. For example, NaN's, infinities, and other special values are
1933 represented in their IEEE hexadecimal format so that assembly and disassembly
1934 do not cause any bits to change in the constants.</p>
1935
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1936<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1937 represented using the 16-digit form shown above (which matches the IEEE754
1938 representation for double); float values must, however, be exactly
1939 representable as IEE754 single precision. Hexadecimal format is always used
1940 for long double, and there are three forms of long double. The 80-bit format
1941 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1942 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1943 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1944 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1945 currently supported target uses this format. Long doubles will only work if
1946 they match the long double format on your target. All hexadecimal formats
1947 are big-endian (sign bit at the left).</p>
1948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1949</div>
1950
1951<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1952<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1953<a name="aggregateconstants"></a> <!-- old anchor -->
1954<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1955</div>
1956
1957<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1958
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1959<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1960 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1961
1962<dl>
1963 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1964 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1965 type definitions (a comma separated list of elements, surrounded by braces
1966 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1967 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1968 Structure constants must have <a href="#t_struct">structure type</a>, and
1969 the number and types of elements must match those specified by the
1970 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1971
1972 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1973 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1974 definitions (a comma separated list of elements, surrounded by square
1975 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1976 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1977 the number and types of elements must match those specified by the
1978 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1979
1980 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1981 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1982 definitions (a comma separated list of elements, surrounded by
1983 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1984 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1985 have <a href="#t_vector">vector type</a>, and the number and types of
1986 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1987
1988 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1989 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1990 value to zero of <em>any</em> type, including scalar and aggregate types.
1991 This is often used to avoid having to print large zero initializers
1992 (e.g. for large arrays) and is always exactly equivalent to using explicit
1993 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1994
1995 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1996 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1997 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1998 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1999 be interpreted as part of the instruction stream, metadata is a place to
2000 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2001</dl>
2002
2003</div>
2004
2005<!-- ======================================================================= -->
2006<div class="doc_subsection">
2007 <a name="globalconstants">Global Variable and Function Addresses</a>
2008</div>
2009
2010<div class="doc_text">
2011
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2012<p>The addresses of <a href="#globalvars">global variables</a>
2013 and <a href="#functionstructure">functions</a> are always implicitly valid
2014 (link-time) constants. These constants are explicitly referenced when
2015 the <a href="#identifiers">identifier for the global</a> is used and always
2016 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2017 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2018
2019<div class="doc_code">
2020<pre>
2021@X = global i32 17
2022@Y = global i32 42
2023@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2024</pre>
2025</div>
2026
2027</div>
2028
2029<!-- ======================================================================= -->
2030<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2031<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2032
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2033<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2034 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2035 Undefined values may be of any type (other than label or void) and be used
2036 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2037
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2038<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2039 program is well defined no matter what value is used. This gives the
2040 compiler more freedom to optimize. Here are some examples of (potentially
2041 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2042
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2043
2044<div class="doc_code">
2045<pre>
2046 %A = add %X, undef
2047 %B = sub %X, undef
2048 %C = xor %X, undef
2049Safe:
2050 %A = undef
2051 %B = undef
2052 %C = undef
2053</pre>
2054</div>
2055
2056<p>This is safe because all of the output bits are affected by the undef bits.
2057Any output bit can have a zero or one depending on the input bits.</p>
2058
2059<div class="doc_code">
2060<pre>
2061 %A = or %X, undef
2062 %B = and %X, undef
2063Safe:
2064 %A = -1
2065 %B = 0
2066Unsafe:
2067 %A = undef
2068 %B = undef
2069</pre>
2070</div>
2071
2072<p>These logical operations have bits that are not always affected by the input.
2073For example, if "%X" has a zero bit, then the output of the 'and' operation will
2074always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2075such, it is unsafe to optimize or assume that the result of the and is undef.
2076However, it is safe to assume that all bits of the undef could be 0, and
2077optimize the and to 0. Likewise, it is safe to assume that all the bits of
2078the undef operand to the or could be set, allowing the or to be folded to
2079-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2080
2081<div class="doc_code">
2082<pre>
2083 %A = select undef, %X, %Y
2084 %B = select undef, 42, %Y
2085 %C = select %X, %Y, undef
2086Safe:
2087 %A = %X (or %Y)
2088 %B = 42 (or %Y)
2089 %C = %Y
2090Unsafe:
2091 %A = undef
2092 %B = undef
2093 %C = undef
2094</pre>
2095</div>
2096
2097<p>This set of examples show that undefined select (and conditional branch)
2098conditions can go "either way" but they have to come from one of the two
2099operands. In the %A example, if %X and %Y were both known to have a clear low
2100bit, then %A would have to have a cleared low bit. However, in the %C example,
2101the optimizer is allowed to assume that the undef operand could be the same as
2102%Y, allowing the whole select to be eliminated.</p>
2103
2104
2105<div class="doc_code">
2106<pre>
2107 %A = xor undef, undef
2108
2109 %B = undef
2110 %C = xor %B, %B
2111
2112 %D = undef
2113 %E = icmp lt %D, 4
2114 %F = icmp gte %D, 4
2115
2116Safe:
2117 %A = undef
2118 %B = undef
2119 %C = undef
2120 %D = undef
2121 %E = undef
2122 %F = undef
2123</pre>
2124</div>
2125
2126<p>This example points out that two undef operands are not necessarily the same.
2127This can be surprising to people (and also matches C semantics) where they
2128assume that "X^X" is always zero, even if X is undef. This isn't true for a
2129number of reasons, but the short answer is that an undef "variable" can
2130arbitrarily change its value over its "live range". This is true because the
2131"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2132logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2133so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2134to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2135would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2136
2137<div class="doc_code">
2138<pre>
2139 %A = fdiv undef, %X
2140 %B = fdiv %X, undef
2141Safe:
2142 %A = undef
2143b: unreachable
2144</pre>
2145</div>
2146
2147<p>These examples show the crucial difference between an <em>undefined
2148value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2149allowed to have an arbitrary bit-pattern. This means that the %A operation
2150can be constant folded to undef because the undef could be an SNaN, and fdiv is
2151not (currently) defined on SNaN's. However, in the second example, we can make
2152a more aggressive assumption: because the undef is allowed to be an arbitrary
2153value, we are allowed to assume that it could be zero. Since a divide by zero
Chris Lattner83d45d72009-09-08 19:45:34 +0000[diff] [blame]2154has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2155does not execute at all. This allows us to delete the divide and all code after
2156it: since the undefined operation "can't happen", the optimizer can assume that
2157it occurs in dead code.
2158</p>
2159
2160<div class="doc_code">
2161<pre>
2162a: store undef -> %X
2163b: store %X -> undef
2164Safe:
2165a: &lt;deleted&gt;
2166b: unreachable
2167</pre>
2168</div>
2169
2170<p>These examples reiterate the fdiv example: a store "of" an undefined value
2171can be assumed to not have any effect: we can assume that the value is
2172overwritten with bits that happen to match what was already there. However, a
2173store "to" an undefined location could clobber arbitrary memory, therefore, it
2174has undefined behavior.</p>
2175
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2176</div>
2177
2178<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2179<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2180 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2181<div class="doc_text">
2182
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2183<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2184
2185<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2186 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2187 the address of the entry block is illegal.</p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2188
2189<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2190 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2191 against null. Pointer equality tests between labels addresses is undefined
2192 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2193 equal to the null pointer. This may also be passed around as an opaque
2194 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2195 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2196 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2197
2198<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2199 using the value as the operand to an inline assembly, but that is target
2200 specific.
2201 </p>
2202
2203</div>
2204
2205
2206<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2207<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2208</div>
2209
2210<div class="doc_text">
2211
2212<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2213 to be used as constants. Constant expressions may be of
2214 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2215 operation that does not have side effects (e.g. load and call are not
2216 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2217
2218<dl>
2219 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2220 <dd>Truncate a constant to another type. The bit size of CST must be larger
2221 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2222
2223 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2224 <dd>Zero extend a constant to another type. The bit size of CST must be
2225 smaller or equal to the bit size of TYPE. Both types must be
2226 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2227
2228 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2229 <dd>Sign extend a constant to another type. The bit size of CST must be
2230 smaller or equal to the bit size of TYPE. Both types must be
2231 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2232
2233 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2234 <dd>Truncate a floating point constant to another floating point type. The
2235 size of CST must be larger than the size of TYPE. Both types must be
2236 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2237
2238 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2239 <dd>Floating point extend a constant to another type. The size of CST must be
2240 smaller or equal to the size of TYPE. Both types must be floating
2241 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2243 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2245 constant. TYPE must be a scalar or vector integer type. CST must be of
2246 scalar or vector floating point type. Both CST and TYPE must be scalars,
2247 or vectors of the same number of elements. If the value won't fit in the
2248 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2249
2250 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2251 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2252 constant. TYPE must be a scalar or vector integer type. CST must be of
2253 scalar or vector floating point type. Both CST and TYPE must be scalars,
2254 or vectors of the same number of elements. If the value won't fit in the
2255 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2256
2257 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2258 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2259 constant. TYPE must be a scalar or vector floating point type. CST must be
2260 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2261 vectors of the same number of elements. If the value won't fit in the
2262 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263
2264 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2265 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2266 constant. TYPE must be a scalar or vector floating point type. CST must be
2267 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2268 vectors of the same number of elements. If the value won't fit in the
2269 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2270
2271 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2272 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2273 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2274 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2275 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2276
2277 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2278 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2279 type. CST must be of integer type. The CST value is zero extended,
2280 truncated, or unchanged to make it fit in a pointer size. This one is
2281 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2282
2283 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2284 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2285 are the same as those for the <a href="#i_bitcast">bitcast
2286 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287
2288 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2289 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2290 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2291 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2292 instruction, the index list may have zero or more indexes, which are
2293 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2294
2295 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2296 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2297
2298 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2299 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2300
2301 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2302 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2303
2304 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2305 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2306 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2307
2308 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2309 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2310 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311
2312 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2313 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2314 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2315
2316 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2317 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2318 be any of the <a href="#binaryops">binary</a>
2319 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2320 on operands are the same as those for the corresponding instruction
2321 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2322</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2324</div>
2325
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2326<!-- ======================================================================= -->
2327<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2328</div>
2329
2330<div class="doc_text">
2331
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2332<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2333 stream without affecting the behaviour of the program. There are two
2334 metadata primitives, strings and nodes. All metadata has the
2335 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2336 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2337
2338<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2339 any character by escaping non-printable characters with "\xx" where "xx" is
2340 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2341
2342<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2343 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2344 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2345 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2346
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2347<p>A metadata node will attempt to track changes to the values it holds. In the
2348 event that a value is deleted, it will be replaced with a typeless
2349 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2350
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2351<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2352 the program that isn't available in the instructions, or that isn't easily
2353 computable. Similarly, the code generator may expect a certain metadata
2354 format to be used to express debugging information.</p>
2355
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2356</div>
2357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2358<!-- *********************************************************************** -->
2359<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2360<!-- *********************************************************************** -->
2361
2362<!-- ======================================================================= -->
2363<div class="doc_subsection">
2364<a name="inlineasm">Inline Assembler Expressions</a>
2365</div>
2366
2367<div class="doc_text">
2368
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2369<p>LLVM supports inline assembler expressions (as opposed
2370 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2371 a special value. This value represents the inline assembler as a string
2372 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2373 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2374 expression has side effects, and a flag indicating whether the function
2375 containing the asm needs to align its stack conservatively. An example
2376 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2377
2378<div class="doc_code">
2379<pre>
2380i32 (i32) asm "bswap $0", "=r,r"
2381</pre>
2382</div>
2383
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2384<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2385 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2386 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387
2388<div class="doc_code">
2389<pre>
2390%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2391</pre>
2392</div>
2393
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2394<p>Inline asms with side effects not visible in the constraint list must be
2395 marked as having side effects. This is done through the use of the
2396 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2397
2398<div class="doc_code">
2399<pre>
2400call void asm sideeffect "eieio", ""()
2401</pre>
2402</div>
2403
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2404<p>In some cases inline asms will contain code that will not work unless the
2405 stack is aligned in some way, such as calls or SSE instructions on x86,
2406 yet will not contain code that does that alignment within the asm.
2407 The compiler should make conservative assumptions about what the asm might
2408 contain and should generate its usual stack alignment code in the prologue
2409 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2410
2411<div class="doc_code">
2412<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2413call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2414</pre>
2415</div>
2416
2417<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2418 first.</p>
2419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2420<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2421 documented here. Constraints on what can be done (e.g. duplication, moving,
2422 etc need to be documented). This is probably best done by reference to
2423 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2424
2425</div>
2426
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2427
2428<!-- *********************************************************************** -->
2429<div class="doc_section">
2430 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2431</div>
2432<!-- *********************************************************************** -->
2433
2434<p>LLVM has a number of "magic" global variables that contain data that affect
2435code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2436of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2437section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2438by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2439
2440<!-- ======================================================================= -->
2441<div class="doc_subsection">
2442<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2443</div>
2444
2445<div class="doc_text">
2446
2447<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2448href="#linkage_appending">appending linkage</a>. This array contains a list of
2449pointers to global variables and functions which may optionally have a pointer
2450cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2451
2452<pre>
2453 @X = global i8 4
2454 @Y = global i32 123
2455
2456 @llvm.used = appending global [2 x i8*] [
2457 i8* @X,
2458 i8* bitcast (i32* @Y to i8*)
2459 ], section "llvm.metadata"
2460</pre>
2461
2462<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2463compiler, assembler, and linker are required to treat the symbol as if there is
2464a reference to the global that it cannot see. For example, if a variable has
2465internal linkage and no references other than that from the <tt>@llvm.used</tt>
2466list, it cannot be deleted. This is commonly used to represent references from
2467inline asms and other things the compiler cannot "see", and corresponds to
2468"attribute((used))" in GNU C.</p>
2469
2470<p>On some targets, the code generator must emit a directive to the assembler or
2471object file to prevent the assembler and linker from molesting the symbol.</p>
2472
2473</div>
2474
2475<!-- ======================================================================= -->
2476<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2477<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2478</div>
2479
2480<div class="doc_text">
2481
2482<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2483<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2484touching the symbol. On targets that support it, this allows an intelligent
2485linker to optimize references to the symbol without being impeded as it would be
2486by <tt>@llvm.used</tt>.</p>
2487
2488<p>This is a rare construct that should only be used in rare circumstances, and
2489should not be exposed to source languages.</p>
2490
2491</div>
2492
2493<!-- ======================================================================= -->
2494<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2495<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2496</div>
2497
2498<div class="doc_text">
2499
2500<p>TODO: Describe this.</p>
2501
2502</div>
2503
2504<!-- ======================================================================= -->
2505<div class="doc_subsection">
2506<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2507</div>
2508
2509<div class="doc_text">
2510
2511<p>TODO: Describe this.</p>
2512
2513</div>
2514
2515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2516<!-- *********************************************************************** -->
2517<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2518<!-- *********************************************************************** -->
2519
2520<div class="doc_text">
2521
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2522<p>The LLVM instruction set consists of several different classifications of
2523 instructions: <a href="#terminators">terminator
2524 instructions</a>, <a href="#binaryops">binary instructions</a>,
2525 <a href="#bitwiseops">bitwise binary instructions</a>,
2526 <a href="#memoryops">memory instructions</a>, and
2527 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2528
2529</div>
2530
2531<!-- ======================================================================= -->
2532<div class="doc_subsection"> <a name="terminators">Terminator
2533Instructions</a> </div>
2534
2535<div class="doc_text">
2536
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2537<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2538 in a program ends with a "Terminator" instruction, which indicates which
2539 block should be executed after the current block is finished. These
2540 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2541 control flow, not values (the one exception being the
2542 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2543
2544<p>There are six different terminator instructions: the
2545 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2546 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2547 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2548 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2549 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2550 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2551 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552
2553</div>
2554
2555<!-- _______________________________________________________________________ -->
2556<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2557Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2558
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2562<pre>
2563 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]2564 ret void <i>; Return from void function</i>
2565</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2567<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2568<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2569 a value) from a function back to the caller.</p>
2570
2571<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2572 value and then causes control flow, and one that just causes control flow to
2573 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2574
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2576<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2577 return value. The type of the return value must be a
2578 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2579
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2580<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2581 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2582 value or a return value with a type that does not match its type, or if it
2583 has a void return type and contains a '<tt>ret</tt>' instruction with a
2584 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2585
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2586<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2587<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2588 the calling function's context. If the caller is a
2589 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2590 instruction after the call. If the caller was an
2591 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2592 the beginning of the "normal" destination block. If the instruction returns
2593 a value, that value shall set the call or invoke instruction's return
2594 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2596<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2597<pre>
2598 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2599 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2600 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]2601</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2602
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2603<p>Note that the code generator does not yet fully support large
2604 return values. The specific sizes that are currently supported are
2605 dependent on the target. For integers, on 32-bit targets the limit
2606 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2607 For aggregate types, the current limits are dependent on the element
2608 types; for example targets are often limited to 2 total integer
2609 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2611</div>
2612<!-- _______________________________________________________________________ -->
2613<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2616
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2617<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2618<pre>
2619 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]2620</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2621
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2622<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2623<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2624 different basic block in the current function. There are two forms of this
2625 instruction, corresponding to a conditional branch and an unconditional
2626 branch.</p>
2627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2629<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2630 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2631 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2632 target.</p>
2633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634<h5>Semantics:</h5>
2635<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2636 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2637 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2638 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2640<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2641<pre>
2642Test:
2643 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2644 br i1 %cond, label %IfEqual, label %IfUnequal
2645IfEqual:
2646 <a href="#i_ret">ret</a> i32 1
2647IfUnequal:
2648 <a href="#i_ret">ret</a> i32 0
2649</pre>
2650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2651</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653<!-- _______________________________________________________________________ -->
2654<div class="doc_subsubsection">
2655 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2656</div>
2657
2658<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2660<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2661<pre>
2662 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2663</pre>
2664
2665<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666<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]2667 several different places. It is a generalization of the '<tt>br</tt>'
2668 instruction, allowing a branch to occur to one of many possible
2669 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670
2671<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2672<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2673 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2674 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2675 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2676
2677<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2678<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2679 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2680 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2681 transferred to the corresponding destination; otherwise, control flow is
2682 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2683
2684<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2686 <tt>switch</tt> instruction, this instruction may be code generated in
2687 different ways. For example, it could be generated as a series of chained
2688 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2689
2690<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2691<pre>
2692 <i>; Emulate a conditional br instruction</i>
2693 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2694 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695
2696 <i>; Emulate an unconditional br instruction</i>
2697 switch i32 0, label %dest [ ]
2698
2699 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2700 switch i32 %val, label %otherwise [ i32 0, label %onzero
2701 i32 1, label %onone
2702 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2705</div>
2706
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2707
2708<!-- _______________________________________________________________________ -->
2709<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2710 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2711</div>
2712
2713<div class="doc_text">
2714
2715<h5>Syntax:</h5>
2716<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2717 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2718</pre>
2719
2720<h5>Overview:</h5>
2721
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2722<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2723 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2724 "<tt>address</tt>". Address must be derived from a <a
2725 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2726
2727<h5>Arguments:</h5>
2728
2729<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2730 rest of the arguments indicate the full set of possible destinations that the
2731 address may point to. Blocks are allowed to occur multiple times in the
2732 destination list, though this isn't particularly useful.</p>
2733
2734<p>This destination list is required so that dataflow analysis has an accurate
2735 understanding of the CFG.</p>
2736
2737<h5>Semantics:</h5>
2738
2739<p>Control transfers to the block specified in the address argument. All
2740 possible destination blocks must be listed in the label list, otherwise this
2741 instruction has undefined behavior. This implies that jumps to labels
2742 defined in other functions have undefined behavior as well.</p>
2743
2744<h5>Implementation:</h5>
2745
2746<p>This is typically implemented with a jump through a register.</p>
2747
2748<h5>Example:</h5>
2749<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2750 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2751</pre>
2752
2753</div>
2754
2755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756<!-- _______________________________________________________________________ -->
2757<div class="doc_subsubsection">
2758 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2759</div>
2760
2761<div class="doc_text">
2762
2763<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2764<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2765 &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]2766 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2767</pre>
2768
2769<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2770<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2771 function, with the possibility of control flow transfer to either the
2772 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2773 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2774 control flow will return to the "normal" label. If the callee (or any
2775 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2776 instruction, control is interrupted and continued at the dynamically nearest
2777 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2778
2779<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2780<p>This instruction requires several arguments:</p>
2781
2782<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2783 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2784 convention</a> the call should use. If none is specified, the call
2785 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2786
2787 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2788 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2789 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2790
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2791 <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]2792 function value being invoked. In most cases, this is a direct function
2793 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2794 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795
2796 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2797 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798
2799 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2800 signature argument types. If the function signature indicates the
2801 function accepts a variable number of arguments, the extra arguments can
2802 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803
2804 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2805 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2806
2807 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2808 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2810 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2811 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2812 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2813</ol>
2814
2815<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2816<p>This instruction is designed to operate as a standard
2817 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2818 primary difference is that it establishes an association with a label, which
2819 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2820
2821<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2822 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2823 exception. Additionally, this is important for implementation of
2824 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2825
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2826<p>For the purposes of the SSA form, the definition of the value returned by the
2827 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2828 block to the "normal" label. If the callee unwinds then no return value is
2829 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2831<h5>Example:</h5>
2832<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2833 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2834 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2835 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2836 unwind label %TestCleanup <i>; {i32}:retval set</i>
2837</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2839</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840
2841<!-- _______________________________________________________________________ -->
2842
2843<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2844Instruction</a> </div>
2845
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
2849<pre>
2850 unwind
2851</pre>
2852
2853<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2855 at the first callee in the dynamic call stack which used
2856 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2857 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858
2859<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2860<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2861 immediately halt. The dynamic call stack is then searched for the
2862 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2863 Once found, execution continues at the "exceptional" destination block
2864 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2865 instruction in the dynamic call chain, undefined behavior results.</p>
2866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2867</div>
2868
2869<!-- _______________________________________________________________________ -->
2870
2871<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2872Instruction</a> </div>
2873
2874<div class="doc_text">
2875
2876<h5>Syntax:</h5>
2877<pre>
2878 unreachable
2879</pre>
2880
2881<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2882<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2883 instruction is used to inform the optimizer that a particular portion of the
2884 code is not reachable. This can be used to indicate that the code after a
2885 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2886
2887<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2890</div>
2891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2892<!-- ======================================================================= -->
2893<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2895<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2896
2897<p>Binary operators are used to do most of the computation in a program. They
2898 require two operands of the same type, execute an operation on them, and
2899 produce a single value. The operands might represent multiple data, as is
2900 the case with the <a href="#t_vector">vector</a> data type. The result value
2901 has the same type as its operands.</p>
2902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2905</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2907<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2908<div class="doc_subsubsection">
2909 <a name="i_add">'<tt>add</tt>' Instruction</a>
2910</div>
2911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2912<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2914<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2915<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2916 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]2917 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2918 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2919 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2922<h5>Overview:</h5>
2923<p>The '<tt>add</tt>' instruction returns the sum of its 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>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2926<p>The two arguments to the '<tt>add</tt>' instruction must
2927 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2928 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2931<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2932
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2933<p>If the sum has unsigned overflow, the result returned is the mathematical
2934 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]2935
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2936<p>Because LLVM integers use a two's complement representation, this instruction
2937 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2938
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2939<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2940 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2941 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2942 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2944<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2945<pre>
2946 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2947</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2949</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2951<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2952<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2953 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2954</div>
2955
2956<div class="doc_text">
2957
2958<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2959<pre>
2960 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2961</pre>
2962
2963<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2964<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2965
2966<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2967<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2968 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2969 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2970
2971<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2972<p>The value produced is the floating point sum of the two operands.</p>
2973
2974<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2975<pre>
2976 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2977</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2978
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2979</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2980
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2981<!-- _______________________________________________________________________ -->
2982<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2983 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2984</div>
2985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2986<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2988<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2989<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2990 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]2991 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2992 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2993 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2994</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2995
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2996<h5>Overview:</h5>
2997<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2998 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2999
3000<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3001 '<tt>neg</tt>' instruction present in most other intermediate
3002 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3004<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3005<p>The two arguments to the '<tt>sub</tt>' instruction must
3006 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3007 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3009<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3010<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3011
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3012<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3013 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3014 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3015
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3016<p>Because LLVM integers use a two's complement representation, this instruction
3017 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3018
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3019<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3020 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3021 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3022 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3024<h5>Example:</h5>
3025<pre>
3026 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3027 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3028</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3032<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3033<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3034 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3035</div>
3036
3037<div class="doc_text">
3038
3039<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3040<pre>
3041 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3042</pre>
3043
3044<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3045<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3046 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3047
3048<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3049 '<tt>fneg</tt>' instruction present in most other intermediate
3050 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3051
3052<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3053<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3054 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3055 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3056
3057<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3058<p>The value produced is the floating point difference of the two operands.</p>
3059
3060<h5>Example:</h5>
3061<pre>
3062 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3063 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3064</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3065
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3066</div>
3067
3068<!-- _______________________________________________________________________ -->
3069<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3070 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3071</div>
3072
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3073<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3074
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3075<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3076<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3077 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3078 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3079 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3080 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3081</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3083<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3086<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3087<p>The two arguments to the '<tt>mul</tt>' instruction must
3088 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3089 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3090
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3091<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3092<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3093
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3094<p>If the result of the multiplication has unsigned overflow, the result
3095 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3096 width of the result.</p>
3097
3098<p>Because LLVM integers use a two's complement representation, and the result
3099 is the same width as the operands, this instruction returns the correct
3100 result for both signed and unsigned integers. If a full product
3101 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3102 be sign-extended or zero-extended as appropriate to the width of the full
3103 product.</p>
3104
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3105<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3106 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3107 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3108 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3110<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3111<pre>
3112 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3113</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3114
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3115</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3116
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3117<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3118<div class="doc_subsubsection">
3119 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3120</div>
3121
3122<div class="doc_text">
3123
3124<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3125<pre>
3126 &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]3127</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3128
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3129<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3130<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3131
3132<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3133<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3134 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3135 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3136
3137<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3138<p>The value produced is the floating point product of the two operands.</p>
3139
3140<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3141<pre>
3142 &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]3143</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3144
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3145</div>
3146
3147<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3148<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3149</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3150
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3151<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3154<pre>
3155 &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]3156</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3158<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3159<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161<h5>Arguments:</h5>
3162<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3163 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3164 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3165
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3166<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3167<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3168
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3169<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3170 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3171
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3172<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175<pre>
3176 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3177</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3179</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3181<!-- _______________________________________________________________________ -->
3182<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3183</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3185<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3187<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3188<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3189 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanb3b03482009-09-02 17:31:42 +0000[diff] [blame]3190 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3194<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3195
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3196<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3197<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3198 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3199 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3200
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3201<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3202<p>The value produced is the signed integer quotient of the two operands rounded
3203 towards zero.</p>
3204
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3205<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3206 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3207
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3208<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3209 undefined behavior; this is a rare case, but can occur, for example, by doing
3210 a 32-bit division of -2147483648 by -1.</p>
3211
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3212<p>If the <tt>exact</tt> keyword is present, the result value of the
3213 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3214 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3216<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3217<pre>
3218 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3219</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3221</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223<!-- _______________________________________________________________________ -->
3224<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3225Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3227<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3229<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3230<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3231 &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]3232</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3233
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3234<h5>Overview:</h5>
3235<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3236
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3237<h5>Arguments:</h5>
3238<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3239 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3240 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3242<h5>Semantics:</h5>
3243<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3245<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3246<pre>
3247 &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]3248</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3249
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3250</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3252<!-- _______________________________________________________________________ -->
3253<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3254</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3256<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3258<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3259<pre>
3260 &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]3261</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3263<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3264<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3265 division of its two arguments.</p>
3266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3267<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3268<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3269 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3270 values. Both arguments must have identical types.</p>
3271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3272<h5>Semantics:</h5>
3273<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3274 This instruction always performs an unsigned division to get the
3275 remainder.</p>
3276
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3277<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3279
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3280<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3281
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3282<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3283<pre>
3284 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3285</pre>
3286
3287</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3289<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3290<div class="doc_subsubsection">
3291 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3292</div>
3293
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3294<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3296<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3297<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3298 &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]3299</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3302<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3303 division of its two operands. This instruction can also take
3304 <a href="#t_vector">vector</a> versions of the values in which case the
3305 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3306
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3307<h5>Arguments:</h5>
3308<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3309 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3310 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3312<h5>Semantics:</h5>
3313<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3314 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3315 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3316 a value. For more information about the difference,
3317 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3318 Math Forum</a>. For a table of how this is implemented in various languages,
3319 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3320 Wikipedia: modulo operation</a>.</p>
3321
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3322<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3323 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3324
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3325<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3326 Overflow also leads to undefined behavior; this is a rare case, but can
3327 occur, for example, by taking the remainder of a 32-bit division of
3328 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3329 lets srem be implemented using instructions that return both the result of
3330 the division and the remainder.)</p>
3331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3332<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3333<pre>
3334 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3335</pre>
3336
3337</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3340<div class="doc_subsubsection">
3341 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3343<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3345<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3346<pre>
3347 &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]3348</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3351<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3352 its two operands.</p>
3353
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3354<h5>Arguments:</h5>
3355<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3356 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3357 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3358
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3359<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360<p>This instruction returns the <i>remainder</i> of a division. The remainder
3361 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3363<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3364<pre>
3365 &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]3366</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3368</div>
3369
3370<!-- ======================================================================= -->
3371<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3372Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3373
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3374<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3375
3376<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3377 program. They are generally very efficient instructions and can commonly be
3378 strength reduced from other instructions. They require two operands of the
3379 same type, execute an operation on them, and produce a single value. The
3380 resulting value is the same type as its operands.</p>
3381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3382</div>
3383
3384<!-- _______________________________________________________________________ -->
3385<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3386Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3387
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3388<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3391<pre>
3392 &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]3393</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3394
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3395<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3397 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3400<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3401 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3402 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3404<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3405<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3406 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3407 is (statically or dynamically) negative or equal to or larger than the number
3408 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3409 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3410 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3411
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3412<h5>Example:</h5>
3413<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3414 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3415 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3416 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3417 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3418 &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]3419</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3421</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3423<!-- _______________________________________________________________________ -->
3424<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3425Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3427<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3428
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3430<pre>
3431 &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]3432</pre>
3433
3434<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3435<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3436 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437
3438<h5>Arguments:</h5>
3439<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3440 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3441 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442
3443<h5>Semantics:</h5>
3444<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3445 significant bits of the result will be filled with zero bits after the shift.
3446 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3447 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3448 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3449 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450
3451<h5>Example:</h5>
3452<pre>
3453 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3454 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3455 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3456 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3457 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3458 &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]3459</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3461</div>
3462
3463<!-- _______________________________________________________________________ -->
3464<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3465Instruction</a> </div>
3466<div class="doc_text">
3467
3468<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3469<pre>
3470 &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]3471</pre>
3472
3473<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3474<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3475 operand shifted to the right a specified number of bits with sign
3476 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3477
3478<h5>Arguments:</h5>
3479<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3480 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3481 type. '<tt>op2</tt>' is treated as an unsigned value.</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>This instruction always performs an arithmetic shift right operation, The
3485 most significant bits of the result will be filled with the sign bit
3486 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3487 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3488 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3489 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490
3491<h5>Example:</h5>
3492<pre>
3493 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3494 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3495 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3496 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3497 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3498 &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]3499</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3501</div>
3502
3503<!-- _______________________________________________________________________ -->
3504<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3505Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3507<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3509<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3510<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3511 &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]3512</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3514<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3515<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3516 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3519<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3520 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3521 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3523<h5>Semantics:</h5>
3524<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3526<table border="1" cellspacing="0" cellpadding="4">
3527 <tbody>
3528 <tr>
3529 <td>In0</td>
3530 <td>In1</td>
3531 <td>Out</td>
3532 </tr>
3533 <tr>
3534 <td>0</td>
3535 <td>0</td>
3536 <td>0</td>
3537 </tr>
3538 <tr>
3539 <td>0</td>
3540 <td>1</td>
3541 <td>0</td>
3542 </tr>
3543 <tr>
3544 <td>1</td>
3545 <td>0</td>
3546 <td>0</td>
3547 </tr>
3548 <tr>
3549 <td>1</td>
3550 <td>1</td>
3551 <td>1</td>
3552 </tr>
3553 </tbody>
3554</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3557<pre>
3558 &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]3559 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3560 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3561</pre>
3562</div>
3563<!-- _______________________________________________________________________ -->
3564<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3565
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3566<div class="doc_text">
3567
3568<h5>Syntax:</h5>
3569<pre>
3570 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3571</pre>
3572
3573<h5>Overview:</h5>
3574<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3575 two operands.</p>
3576
3577<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3578<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3579 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3580 values. Both arguments must have identical types.</p>
3581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3582<h5>Semantics:</h5>
3583<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3585<table border="1" cellspacing="0" cellpadding="4">
3586 <tbody>
3587 <tr>
3588 <td>In0</td>
3589 <td>In1</td>
3590 <td>Out</td>
3591 </tr>
3592 <tr>
3593 <td>0</td>
3594 <td>0</td>
3595 <td>0</td>
3596 </tr>
3597 <tr>
3598 <td>0</td>
3599 <td>1</td>
3600 <td>1</td>
3601 </tr>
3602 <tr>
3603 <td>1</td>
3604 <td>0</td>
3605 <td>1</td>
3606 </tr>
3607 <tr>
3608 <td>1</td>
3609 <td>1</td>
3610 <td>1</td>
3611 </tr>
3612 </tbody>
3613</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3615<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3616<pre>
3617 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3619 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3620</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3621
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3622</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<!-- _______________________________________________________________________ -->
3625<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3626Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3628<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3630<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3631<pre>
3632 &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]3633</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3634
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3635<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3636<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3637 its two operands. The <tt>xor</tt> is used to implement the "one's
3638 complement" operation, which is the "~" operator in C.</p>
3639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3641<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3642 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3643 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3645<h5>Semantics:</h5>
3646<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3647
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648<table border="1" cellspacing="0" cellpadding="4">
3649 <tbody>
3650 <tr>
3651 <td>In0</td>
3652 <td>In1</td>
3653 <td>Out</td>
3654 </tr>
3655 <tr>
3656 <td>0</td>
3657 <td>0</td>
3658 <td>0</td>
3659 </tr>
3660 <tr>
3661 <td>0</td>
3662 <td>1</td>
3663 <td>1</td>
3664 </tr>
3665 <tr>
3666 <td>1</td>
3667 <td>0</td>
3668 <td>1</td>
3669 </tr>
3670 <tr>
3671 <td>1</td>
3672 <td>1</td>
3673 <td>0</td>
3674 </tr>
3675 </tbody>
3676</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3678<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3679<pre>
3680 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3681 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3682 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3683 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3684</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3686</div>
3687
3688<!-- ======================================================================= -->
3689<div class="doc_subsection">
3690 <a name="vectorops">Vector Operations</a>
3691</div>
3692
3693<div class="doc_text">
3694
3695<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3696 target-independent manner. These instructions cover the element-access and
3697 vector-specific operations needed to process vectors effectively. While LLVM
3698 does directly support these vector operations, many sophisticated algorithms
3699 will want to use target-specific intrinsics to take full advantage of a
3700 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3701
3702</div>
3703
3704<!-- _______________________________________________________________________ -->
3705<div class="doc_subsubsection">
3706 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3707</div>
3708
3709<div class="doc_text">
3710
3711<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712<pre>
3713 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3714</pre>
3715
3716<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3717<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3718 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3719
3720
3721<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3722<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3723 of <a href="#t_vector">vector</a> type. The second operand is an index
3724 indicating the position from which to extract the element. The index may be
3725 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3726
3727<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3728<p>The result is a scalar of the same type as the element type of
3729 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3730 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3731 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3732
3733<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3734<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3735 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3736</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3737
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3738</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3739
3740<!-- _______________________________________________________________________ -->
3741<div class="doc_subsubsection">
3742 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3743</div>
3744
3745<div class="doc_text">
3746
3747<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3748<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3749 &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]3750</pre>
3751
3752<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3753<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3754 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3755
3756<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3757<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3758 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3759 whose type must equal the element type of the first operand. The third
3760 operand is an index indicating the position at which to insert the value.
3761 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762
3763<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3764<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3765 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3766 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3767 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768
3769<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3770<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3771 &lt;result&gt; = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3772</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3774</div>
3775
3776<!-- _______________________________________________________________________ -->
3777<div class="doc_subsubsection">
3778 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3779</div>
3780
3781<div class="doc_text">
3782
3783<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3784<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3785 &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]3786</pre>
3787
3788<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3789<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3790 from two input vectors, returning a vector with the same element type as the
3791 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3792
3793<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3794<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3795 with types that match each other. The third argument is a shuffle mask whose
3796 element type is always 'i32'. The result of the instruction is a vector
3797 whose length is the same as the shuffle mask and whose element type is the
3798 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3799
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3800<p>The shuffle mask operand is required to be a constant vector with either
3801 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3802
3803<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3804<p>The elements of the two input vectors are numbered from left to right across
3805 both of the vectors. The shuffle mask operand specifies, for each element of
3806 the result vector, which element of the two input vectors the result element
3807 gets. The element selector may be undef (meaning "don't care") and the
3808 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3809
3810<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3811<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3812 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3813 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3814 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3815 &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.
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3816 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3817 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3818 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3819 &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]3820</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3822</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3823
3824<!-- ======================================================================= -->
3825<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3826 <a name="aggregateops">Aggregate Operations</a>
3827</div>
3828
3829<div class="doc_text">
3830
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3831<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3832
3833</div>
3834
3835<!-- _______________________________________________________________________ -->
3836<div class="doc_subsubsection">
3837 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3838</div>
3839
3840<div class="doc_text">
3841
3842<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3843<pre>
3844 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3845</pre>
3846
3847<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3848<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3849 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3850
3851<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3852<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3853 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3854 operands are constant indices to specify which value to extract in a similar
3855 manner as indices in a
3856 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3857
3858<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3859<p>The result is the value at the position in the aggregate specified by the
3860 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3861
3862<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3863<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3864 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3865</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3866
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3867</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3868
3869<!-- _______________________________________________________________________ -->
3870<div class="doc_subsubsection">
3871 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3872</div>
3873
3874<div class="doc_text">
3875
3876<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3877<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3878 &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]3879</pre>
3880
3881<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3882<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3883 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3884
3885
3886<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3887<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3888 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3889 second operand is a first-class value to insert. The following operands are
3890 constant indices indicating the position at which to insert the value in a
3891 similar manner as indices in a
3892 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3893 value to insert must have the same type as the value identified by the
3894 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3895
3896<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3897<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3898 that of <tt>val</tt> except that the value at the position specified by the
3899 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3900
3901<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3902<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3903 &lt;result&gt; = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3904</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3905
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3906</div>
3907
3908
3909<!-- ======================================================================= -->
3910<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3911 <a name="memoryops">Memory Access and Addressing Operations</a>
3912</div>
3913
3914<div class="doc_text">
3915
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3916<p>A key design point of an SSA-based representation is how it represents
3917 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3918 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3919 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3920
3921</div>
3922
3923<!-- _______________________________________________________________________ -->
3924<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3925 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3926</div>
3927
3928<div class="doc_text">
3929
3930<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3931<pre>
3932 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3933</pre>
3934
3935<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3937 currently executing function, to be automatically released when this function
3938 returns to its caller. The object is always allocated in the generic address
3939 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3940
3941<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3942<p>The '<tt>alloca</tt>' instruction
3943 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3944 runtime stack, returning a pointer of the appropriate type to the program.
3945 If "NumElements" is specified, it is the number of elements allocated,
3946 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3947 specified, the value result of the allocation is guaranteed to be aligned to
3948 at least that boundary. If not specified, or if zero, the target can choose
3949 to align the allocation on any convenient boundary compatible with the
3950 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951
3952<p>'<tt>type</tt>' may be any sized type.</p>
3953
3954<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3955<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3956 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3957 memory is automatically released when the function returns. The
3958 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3959 variables that must have an address available. When the function returns
3960 (either with the <tt><a href="#i_ret">ret</a></tt>
3961 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3962 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3963
3964<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3966 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3967 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3968 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3969 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3970</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3972</div>
3973
3974<!-- _______________________________________________________________________ -->
3975<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3976Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3979
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3980<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3981<pre>
3982 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3983 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3984</pre>
3985
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3986<h5>Overview:</h5>
3987<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3988
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3989<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3990<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3991 from which to load. The pointer must point to
3992 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3993 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3994 number or order of execution of this <tt>load</tt> with other
3995 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3996 instructions. </p>
3997
3998<p>The optional constant "align" argument specifies the alignment of the
3999 operation (that is, the alignment of the memory address). A value of 0 or an
4000 omitted "align" argument means that the operation has the preferential
4001 alignment for the target. It is the responsibility of the code emitter to
4002 ensure that the alignment information is correct. Overestimating the
4003 alignment results in an undefined behavior. Underestimating the alignment may
4004 produce less efficient code. An alignment of 1 is always safe.</p>
4005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4006<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4007<p>The location of memory pointed to is loaded. If the value being loaded is of
4008 scalar type then the number of bytes read does not exceed the minimum number
4009 of bytes needed to hold all bits of the type. For example, loading an
4010 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4011 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4012 is undefined if the value was not originally written using a store of the
4013 same type.</p>
4014
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4016<pre>
4017 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4018 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4019 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4020</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4021
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4022</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4023
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4024<!-- _______________________________________________________________________ -->
4025<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4026Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4027
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4028<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4030<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4031<pre>
4032 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]4033 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4034</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4036<h5>Overview:</h5>
4037<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4040<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4041 and an address at which to store it. The type of the
4042 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4043 the <a href="#t_firstclass">first class</a> type of the
4044 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4045 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4046 or order of execution of this <tt>store</tt> with other
4047 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4048 instructions.</p>
4049
4050<p>The optional constant "align" argument specifies the alignment of the
4051 operation (that is, the alignment of the memory address). A value of 0 or an
4052 omitted "align" argument means that the operation has the preferential
4053 alignment for the target. It is the responsibility of the code emitter to
4054 ensure that the alignment information is correct. Overestimating the
4055 alignment results in an undefined behavior. Underestimating the alignment may
4056 produce less efficient code. An alignment of 1 is always safe.</p>
4057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4058<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4059<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4060 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4061 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4062 does not exceed the minimum number of bytes needed to hold all bits of the
4063 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4064 writing a value of a type like <tt>i20</tt> with a size that is not an
4065 integral number of bytes, it is unspecified what happens to the extra bits
4066 that do not belong to the type, but they will typically be overwritten.</p>
4067
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4068<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4069<pre>
4070 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4071 store i32 3, i32* %ptr <i>; yields {void}</i>
4072 %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]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_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4080</div>
4081
4082<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4083
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084<h5>Syntax:</h5>
4085<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4086 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4087 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088</pre>
4089
4090<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4091<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4092 subelement of an aggregate data structure. It performs address calculation
4093 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4094
4095<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4096<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4097 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4098 elements of the aggregate object are indexed. The interpretation of each
4099 index is dependent on the type being indexed into. The first index always
4100 indexes the pointer value given as the first argument, the second index
4101 indexes a value of the type pointed to (not necessarily the value directly
4102 pointed to, since the first index can be non-zero), etc. The first type
4103 indexed into must be a pointer value, subsequent types can be arrays, vectors
4104 and structs. Note that subsequent types being indexed into can never be
4105 pointers, since that would require loading the pointer before continuing
4106 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4107
4108<p>The type of each index argument depends on the type it is indexing into.
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4109 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4110 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4111 vector, integers of any width are allowed, and they are not required to be
4112 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4113
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4114<p>For example, let's consider a C code fragment and how it gets compiled to
4115 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4116
4117<div class="doc_code">
4118<pre>
4119struct RT {
4120 char A;
4121 int B[10][20];
4122 char C;
4123};
4124struct ST {
4125 int X;
4126 double Y;
4127 struct RT Z;
4128};
4129
4130int *foo(struct ST *s) {
4131 return &amp;s[1].Z.B[5][13];
4132}
4133</pre>
4134</div>
4135
4136<p>The LLVM code generated by the GCC frontend is:</p>
4137
4138<div class="doc_code">
4139<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4140%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4141%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4142
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4143define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4144entry:
4145 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4146 ret i32* %reg
4147}
4148</pre>
4149</div>
4150
4151<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4152<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]4153 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4154 }</tt>' type, a structure. The second index indexes into the third element
4155 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4156 i8 }</tt>' type, another structure. The third index indexes into the second
4157 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4158 array. The two dimensions of the array are subscripted into, yielding an
4159 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4160 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4161
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4162<p>Note that it is perfectly legal to index partially through a structure,
4163 returning a pointer to an inner element. Because of this, the LLVM code for
4164 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4165
4166<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4167 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4168 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4169 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4170 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4171 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4172 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4173 ret i32* %t5
4174 }
4175</pre>
4176
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4177<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4178 <tt>getelementptr</tt> is undefined if the base pointer is not an
4179 <i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4180 that would be formed by successive addition of the offsets implied by the
4181 indices to the base address with infinitely precise arithmetic are not an
4182 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4183 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4184 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4185
4186<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4187 the base address with silently-wrapping two's complement arithmetic, and
4188 the result value of the <tt>getelementptr</tt> may be outside the object
4189 pointed to by the base pointer. The result value may not necessarily be
4190 used to access memory though, even if it happens to point into allocated
4191 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4192 section for more information.</p>
4193
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4194<p>The getelementptr instruction is often confusing. For some more insight into
4195 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4196
4197<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4198<pre>
4199 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4200 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4201 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4202 %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]4203 <i>; yields i8*:eptr</i>
4204 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4205 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4206 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4207</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4208
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4209</div>
4210
4211<!-- ======================================================================= -->
4212<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4213</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4215<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4218 which all take a single operand and a type. They perform various bit
4219 conversions on the operand.</p>
4220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221</div>
4222
4223<!-- _______________________________________________________________________ -->
4224<div class="doc_subsubsection">
4225 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4226</div>
4227<div class="doc_text">
4228
4229<h5>Syntax:</h5>
4230<pre>
4231 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4232</pre>
4233
4234<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4235<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4236 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4237
4238<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4239<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4240 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4241 size and type of the result, which must be
4242 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4243 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4244 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245
4246<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4247<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4248 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4249 source size must be larger than the destination size, <tt>trunc</tt> cannot
4250 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4251
4252<h5>Example:</h5>
4253<pre>
4254 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4255 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4256 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4257</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4259</div>
4260
4261<!-- _______________________________________________________________________ -->
4262<div class="doc_subsubsection">
4263 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4264</div>
4265<div class="doc_text">
4266
4267<h5>Syntax:</h5>
4268<pre>
4269 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4270</pre>
4271
4272<h5>Overview:</h5>
4273<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4274 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4275
4276
4277<h5>Arguments:</h5>
4278<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]4279 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4280 also be of <a href="#t_integer">integer</a> type. The bit size of the
4281 <tt>value</tt> must be smaller than the bit size of the destination type,
4282 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4283
4284<h5>Semantics:</h5>
4285<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]4286 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4287
4288<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4289
4290<h5>Example:</h5>
4291<pre>
4292 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4293 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4294</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4296</div>
4297
4298<!-- _______________________________________________________________________ -->
4299<div class="doc_subsubsection">
4300 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4301</div>
4302<div class="doc_text">
4303
4304<h5>Syntax:</h5>
4305<pre>
4306 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4307</pre>
4308
4309<h5>Overview:</h5>
4310<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4311
4312<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4313<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
4314 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4315 also be of <a href="#t_integer">integer</a> type. The bit size of the
4316 <tt>value</tt> must be smaller than the bit size of the destination type,
4317 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4318
4319<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4320<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4321 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4322 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4323
4324<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4325
4326<h5>Example:</h5>
4327<pre>
4328 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4329 %Y = sext i1 true to i32 <i>; yields i32:-1</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_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4337</div>
4338
4339<div class="doc_text">
4340
4341<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342<pre>
4343 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4344</pre>
4345
4346<h5>Overview:</h5>
4347<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4348 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4349
4350<h5>Arguments:</h5>
4351<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4352 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4353 to cast it to. The size of <tt>value</tt> must be larger than the size of
4354 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4355 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4356
4357<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4358<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4359 <a href="#t_floating">floating point</a> type to a smaller
4360 <a href="#t_floating">floating point</a> type. If the value cannot fit
4361 within the destination type, <tt>ty2</tt>, then the results are
4362 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4363
4364<h5>Example:</h5>
4365<pre>
4366 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4367 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4368</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370</div>
4371
4372<!-- _______________________________________________________________________ -->
4373<div class="doc_subsubsection">
4374 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4375</div>
4376<div class="doc_text">
4377
4378<h5>Syntax:</h5>
4379<pre>
4380 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4381</pre>
4382
4383<h5>Overview:</h5>
4384<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]4385 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4386
4387<h5>Arguments:</h5>
4388<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4389 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4390 a <a href="#t_floating">floating point</a> type to cast it to. The source
4391 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4392
4393<h5>Semantics:</h5>
4394<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4395 <a href="#t_floating">floating point</a> type to a larger
4396 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4397 used to make a <i>no-op cast</i> because it always changes bits. Use
4398 <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]4399
4400<h5>Example:</h5>
4401<pre>
4402 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4403 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4404</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4406</div>
4407
4408<!-- _______________________________________________________________________ -->
4409<div class="doc_subsubsection">
4410 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4411</div>
4412<div class="doc_text">
4413
4414<h5>Syntax:</h5>
4415<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4416 &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]4417</pre>
4418
4419<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4420<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4421 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4422
4423<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4424<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4425 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4426 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4427 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4428 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4429
4430<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4431<p>The '<tt>fptoui</tt>' instruction converts its
4432 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4433 towards zero) unsigned integer value. If the value cannot fit
4434 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4436<h5>Example:</h5>
4437<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4438 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4439 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4440 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4441</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443</div>
4444
4445<!-- _______________________________________________________________________ -->
4446<div class="doc_subsubsection">
4447 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4448</div>
4449<div class="doc_text">
4450
4451<h5>Syntax:</h5>
4452<pre>
4453 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4454</pre>
4455
4456<h5>Overview:</h5>
4457<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4458 <a href="#t_floating">floating point</a> <tt>value</tt> to
4459 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4461<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4462<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4463 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4464 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4465 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4466 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4467
4468<h5>Semantics:</h5>
4469<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4470 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4471 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4472 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474<h5>Example:</h5>
4475<pre>
4476 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4477 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4478 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4479</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4480
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481</div>
4482
4483<!-- _______________________________________________________________________ -->
4484<div class="doc_subsubsection">
4485 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4486</div>
4487<div class="doc_text">
4488
4489<h5>Syntax:</h5>
4490<pre>
4491 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4492</pre>
4493
4494<h5>Overview:</h5>
4495<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4496 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4498<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4499<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]4500 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4501 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4502 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4503 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4504
4505<h5>Semantics:</h5>
4506<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4507 integer quantity and converts it to the corresponding floating point
4508 value. If the value cannot fit in the floating point value, the results are
4509 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511<h5>Example:</h5>
4512<pre>
4513 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4514 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4515</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4517</div>
4518
4519<!-- _______________________________________________________________________ -->
4520<div class="doc_subsubsection">
4521 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4522</div>
4523<div class="doc_text">
4524
4525<h5>Syntax:</h5>
4526<pre>
4527 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4528</pre>
4529
4530<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4531<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4532 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4533
4534<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4535<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]4536 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4537 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4538 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4539 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540
4541<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4543 quantity and converts it to the corresponding floating point value. If the
4544 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4545
4546<h5>Example:</h5>
4547<pre>
4548 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4549 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4550</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4552</div>
4553
4554<!-- _______________________________________________________________________ -->
4555<div class="doc_subsubsection">
4556 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4557</div>
4558<div class="doc_text">
4559
4560<h5>Syntax:</h5>
4561<pre>
4562 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4563</pre>
4564
4565<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4566<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4567 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4568
4569<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4570<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4571 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4572 <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]4573
4574<h5>Semantics:</h5>
4575<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4576 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4577 truncating or zero extending that value to the size of the integer type. If
4578 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4579 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4580 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4581 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4582
4583<h5>Example:</h5>
4584<pre>
4585 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4586 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4587</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4589</div>
4590
4591<!-- _______________________________________________________________________ -->
4592<div class="doc_subsubsection">
4593 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4594</div>
4595<div class="doc_text">
4596
4597<h5>Syntax:</h5>
4598<pre>
4599 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4600</pre>
4601
4602<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4603<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4604 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4605
4606<h5>Arguments:</h5>
4607<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4608 value to cast, and a type to cast it to, which must be a
4609 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610
4611<h5>Semantics:</h5>
4612<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4613 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4614 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4615 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4616 than the size of a pointer then a zero extension is done. If they are the
4617 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4618
4619<h5>Example:</h5>
4620<pre>
4621 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4622 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4623 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4624</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4626</div>
4627
4628<!-- _______________________________________________________________________ -->
4629<div class="doc_subsubsection">
4630 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4631</div>
4632<div class="doc_text">
4633
4634<h5>Syntax:</h5>
4635<pre>
4636 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4637</pre>
4638
4639<h5>Overview:</h5>
4640<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4641 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4642
4643<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4644<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4645 non-aggregate first class value, and a type to cast it to, which must also be
4646 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4647 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4648 identical. If the source type is a pointer, the destination type must also be
4649 a pointer. This instruction supports bitwise conversion of vectors to
4650 integers and to vectors of other types (as long as they have the same
4651 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4652
4653<h5>Semantics:</h5>
4654<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4655 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4656 this conversion. The conversion is done as if the <tt>value</tt> had been
4657 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4658 be converted to other pointer types with this instruction. To convert
4659 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4660 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4661
4662<h5>Example:</h5>
4663<pre>
4664 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4665 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4666 %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]4667</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669</div>
4670
4671<!-- ======================================================================= -->
4672<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4674<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4675
4676<p>The instructions in this category are the "miscellaneous" instructions, which
4677 defy better classification.</p>
4678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4679</div>
4680
4681<!-- _______________________________________________________________________ -->
4682<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4683</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4685<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4687<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4688<pre>
4689 &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]4690</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4692<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4693<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4694 boolean values based on comparison of its two integer, integer vector, or
4695 pointer operands.</p>
4696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697<h5>Arguments:</h5>
4698<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4699 the condition code indicating the kind of comparison to perform. It is not a
4700 value, just a keyword. The possible condition code are:</p>
4701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4702<ol>
4703 <li><tt>eq</tt>: equal</li>
4704 <li><tt>ne</tt>: not equal </li>
4705 <li><tt>ugt</tt>: unsigned greater than</li>
4706 <li><tt>uge</tt>: unsigned greater or equal</li>
4707 <li><tt>ult</tt>: unsigned less than</li>
4708 <li><tt>ule</tt>: unsigned less or equal</li>
4709 <li><tt>sgt</tt>: signed greater than</li>
4710 <li><tt>sge</tt>: signed greater or equal</li>
4711 <li><tt>slt</tt>: signed less than</li>
4712 <li><tt>sle</tt>: signed less or equal</li>
4713</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4715<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4716 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4717 typed. They must also be identical types.</p>
4718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4719<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4720<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4721 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4722 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4723 result, as follows:</p>
4724
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4725<ol>
4726 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>false</tt> otherwise. No sign interpretation is necessary or
4728 performed.</li>
4729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4730 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>false</tt> otherwise. No sign interpretation is necessary or
4732 performed.</li>
4733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4734 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4735 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4737 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4738 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4739 to <tt>op2</tt>.</li>
4740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4741 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4742 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4744 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4745 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4747 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4748 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4750 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4751 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4752 to <tt>op2</tt>.</li>
4753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4754 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4755 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4758 <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]4759</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4760
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4761<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762 values are compared as if they were integers.</p>
4763
4764<p>If the operands are integer vectors, then they are compared element by
4765 element. The result is an <tt>i1</tt> vector with the same number of elements
4766 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4767
4768<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4769<pre>
4770 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4771 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4772 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4773 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4774 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4775 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4776</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4777
4778<p>Note that the code generator does not yet support vector types with
4779 the <tt>icmp</tt> instruction.</p>
4780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4781</div>
4782
4783<!-- _______________________________________________________________________ -->
4784<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4785</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4786
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4787<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4789<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4790<pre>
4791 &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]4792</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4794<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4795<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4796 values based on comparison of its operands.</p>
4797
4798<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4799(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4800
4801<p>If the operands are floating point vectors, then the result type is a vector
4802 of boolean with the same number of elements as the operands being
4803 compared.</p>
4804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4805<h5>Arguments:</h5>
4806<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4807 the condition code indicating the kind of comparison to perform. It is not a
4808 value, just a keyword. The possible condition code are:</p>
4809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4810<ol>
4811 <li><tt>false</tt>: no comparison, always returns false</li>
4812 <li><tt>oeq</tt>: ordered and equal</li>
4813 <li><tt>ogt</tt>: ordered and greater than </li>
4814 <li><tt>oge</tt>: ordered and greater than or equal</li>
4815 <li><tt>olt</tt>: ordered and less than </li>
4816 <li><tt>ole</tt>: ordered and less than or equal</li>
4817 <li><tt>one</tt>: ordered and not equal</li>
4818 <li><tt>ord</tt>: ordered (no nans)</li>
4819 <li><tt>ueq</tt>: unordered or equal</li>
4820 <li><tt>ugt</tt>: unordered or greater than </li>
4821 <li><tt>uge</tt>: unordered or greater than or equal</li>
4822 <li><tt>ult</tt>: unordered or less than </li>
4823 <li><tt>ule</tt>: unordered or less than or equal</li>
4824 <li><tt>une</tt>: unordered or not equal</li>
4825 <li><tt>uno</tt>: unordered (either nans)</li>
4826 <li><tt>true</tt>: no comparison, always returns true</li>
4827</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4828
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4829<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4830 <i>unordered</i> means that either operand may be a QNAN.</p>
4831
4832<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4833 a <a href="#t_floating">floating point</a> type or
4834 a <a href="#t_vector">vector</a> of floating point type. They must have
4835 identical types.</p>
4836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4837<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4838<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4839 according to the condition code given as <tt>cond</tt>. If the operands are
4840 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4841 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4842 follows:</p>
4843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844<ol>
4845 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4847 <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]4848 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850 <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]4851 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4853 <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]4854 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4856 <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]4857 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4858
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4859 <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]4860 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4862 <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]4863 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4865 <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]4866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867 <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]4868 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4869
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4870 <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]4871 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4873 <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]4874 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4876 <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]4877 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4879 <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]4880 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4881
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4882 <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]4883 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4885 <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]4886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4887 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4888</ol>
4889
4890<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4891<pre>
4892 &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]4893 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4894 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4895 &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]4896</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4897
4898<p>Note that the code generator does not yet support vector types with
4899 the <tt>fcmp</tt> instruction.</p>
4900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4901</div>
4902
4903<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4904<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4905 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4906</div>
4907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4908<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4910<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4911<pre>
4912 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4913</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4915<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4916<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4917 SSA graph representing the function.</p>
4918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4919<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4920<p>The type of the incoming values is specified with the first type field. After
4921 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4922 one pair for each predecessor basic block of the current block. Only values
4923 of <a href="#t_firstclass">first class</a> type may be used as the value
4924 arguments to the PHI node. Only labels may be used as the label
4925 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4926
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4927<p>There must be no non-phi instructions between the start of a basic block and
4928 the PHI instructions: i.e. PHI instructions must be first in a basic
4929 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4930
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4931<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4932 occur on the edge from the corresponding predecessor block to the current
4933 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4934 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4936<h5>Semantics:</h5>
4937<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4938 specified by the pair corresponding to the predecessor basic block that
4939 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4941<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4942<pre>
4943Loop: ; Infinite loop that counts from 0 on up...
4944 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4945 %nextindvar = add i32 %indvar, 1
4946 br label %Loop
4947</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4949</div>
4950
4951<!-- _______________________________________________________________________ -->
4952<div class="doc_subsubsection">
4953 <a name="i_select">'<tt>select</tt>' Instruction</a>
4954</div>
4955
4956<div class="doc_text">
4957
4958<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4959<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4960 &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>
4961
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4962 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4963</pre>
4964
4965<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4966<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4967 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4968
4969
4970<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4971<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4972 values indicating the condition, and two values of the
4973 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4974 vectors and the condition is a scalar, then entire vectors are selected, not
4975 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4976
4977<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4978<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4979 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4980
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4981<p>If the condition is a vector of i1, then the value arguments must be vectors
4982 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4983
4984<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4985<pre>
4986 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4987</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4988
4989<p>Note that the code generator does not yet support conditions
4990 with vector type.</p>
4991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4992</div>
4993
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4994<!-- _______________________________________________________________________ -->
4995<div class="doc_subsubsection">
4996 <a name="i_call">'<tt>call</tt>' Instruction</a>
4997</div>
4998
4999<div class="doc_text">
5000
5001<h5>Syntax:</h5>
5002<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5003 &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]5004</pre>
5005
5006<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5007<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5008
5009<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5010<p>This instruction requires several arguments:</p>
5011
5012<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5013 <li>The optional "tail" marker indicates whether the callee function accesses
5014 any allocas or varargs in the caller. If the "tail" marker is present,
5015 the function call is eligible for tail call optimization. Note that calls
5016 may be marked "tail" even if they do not occur before
5017 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5018
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5019 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5020 convention</a> the call should use. If none is specified, the call
5021 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5022
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5023 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5024 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5025 '<tt>inreg</tt>' attributes are valid here.</li>
5026
5027 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5028 type of the return value. Functions that return no value are marked
5029 <tt><a href="#t_void">void</a></tt>.</li>
5030
5031 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5032 being invoked. The argument types must match the types implied by this
5033 signature. This type can be omitted if the function is not varargs and if
5034 the function type does not return a pointer to a function.</li>
5035
5036 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5037 be invoked. In most cases, this is a direct function invocation, but
5038 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5039 to function value.</li>
5040
5041 <li>'<tt>function args</tt>': argument list whose types match the function
5042 signature argument types. All arguments must be of
5043 <a href="#t_firstclass">first class</a> type. If the function signature
5044 indicates the function accepts a variable number of arguments, the extra
5045 arguments can be specified.</li>
5046
5047 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5048 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5049 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5050</ol>
5051
5052<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5053<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5054 a specified function, with its incoming arguments bound to the specified
5055 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5056 function, control flow continues with the instruction after the function
5057 call, and the return value of the function is bound to the result
5058 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5059
5060<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5061<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5062 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5063 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5064 %X = tail call i32 @foo() <i>; yields i32</i>
5065 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5066 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5067
5068 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5069 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5070 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5071 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5072 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5073 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074</pre>
5075
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5076<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5077standard C99 library as being the C99 library functions, and may perform
5078optimizations or generate code for them under that assumption. This is
5079something we'd like to change in the future to provide better support for
5080freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5081
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082</div>
5083
5084<!-- _______________________________________________________________________ -->
5085<div class="doc_subsubsection">
5086 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5087</div>
5088
5089<div class="doc_text">
5090
5091<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092<pre>
5093 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5094</pre>
5095
5096<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5097<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5098 the "variable argument" area of a function call. It is used to implement the
5099 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5100
5101<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5102<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5103 argument. It returns a value of the specified argument type and increments
5104 the <tt>va_list</tt> to point to the next argument. The actual type
5105 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5106
5107<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5108<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5109 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5110 to the next argument. For more information, see the variable argument
5111 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5112
5113<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]5114 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5115 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5116
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5117<p><tt>va_arg</tt> is an LLVM instruction instead of
5118 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5119 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5120
5121<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5122<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5123
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5124<p>Note that the code generator does not yet fully support va_arg on many
5125 targets. Also, it does not currently support va_arg with aggregate types on
5126 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5127
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5128</div>
5129
5130<!-- *********************************************************************** -->
5131<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5132<!-- *********************************************************************** -->
5133
5134<div class="doc_text">
5135
5136<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5137 well known names and semantics and are required to follow certain
5138 restrictions. Overall, these intrinsics represent an extension mechanism for
5139 the LLVM language that does not require changing all of the transformations
5140 in LLVM when adding to the language (or the bitcode reader/writer, the
5141 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5142
5143<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5144 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5145 begin with this prefix. Intrinsic functions must always be external
5146 functions: you cannot define the body of intrinsic functions. Intrinsic
5147 functions may only be used in call or invoke instructions: it is illegal to
5148 take the address of an intrinsic function. Additionally, because intrinsic
5149 functions are part of the LLVM language, it is required if any are added that
5150 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5151
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5152<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5153 family of functions that perform the same operation but on different data
5154 types. Because LLVM can represent over 8 million different integer types,
5155 overloading is used commonly to allow an intrinsic function to operate on any
5156 integer type. One or more of the argument types or the result type can be
5157 overloaded to accept any integer type. Argument types may also be defined as
5158 exactly matching a previous argument's type or the result type. This allows
5159 an intrinsic function which accepts multiple arguments, but needs all of them
5160 to be of the same type, to only be overloaded with respect to a single
5161 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5162
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5163<p>Overloaded intrinsics will have the names of its overloaded argument types
5164 encoded into its function name, each preceded by a period. Only those types
5165 which are overloaded result in a name suffix. Arguments whose type is matched
5166 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5167 can take an integer of any width and returns an integer of exactly the same
5168 integer width. This leads to a family of functions such as
5169 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5170 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5171 suffix is required. Because the argument's type is matched against the return
5172 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5173
5174<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5175 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5176
5177</div>
5178
5179<!-- ======================================================================= -->
5180<div class="doc_subsection">
5181 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5182</div>
5183
5184<div class="doc_text">
5185
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5186<p>Variable argument support is defined in LLVM with
5187 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5188 intrinsic functions. These functions are related to the similarly named
5189 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5191<p>All of these functions operate on arguments that use a target-specific value
5192 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5193 not define what this type is, so all transformations should be prepared to
5194 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5195
5196<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]5197 instruction and the variable argument handling intrinsic functions are
5198 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5199
5200<div class="doc_code">
5201<pre>
5202define i32 @test(i32 %X, ...) {
5203 ; Initialize variable argument processing
5204 %ap = alloca i8*
5205 %ap2 = bitcast i8** %ap to i8*
5206 call void @llvm.va_start(i8* %ap2)
5207
5208 ; Read a single integer argument
5209 %tmp = va_arg i8** %ap, i32
5210
5211 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5212 %aq = alloca i8*
5213 %aq2 = bitcast i8** %aq to i8*
5214 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5215 call void @llvm.va_end(i8* %aq2)
5216
5217 ; Stop processing of arguments.
5218 call void @llvm.va_end(i8* %ap2)
5219 ret i32 %tmp
5220}
5221
5222declare void @llvm.va_start(i8*)
5223declare void @llvm.va_copy(i8*, i8*)
5224declare void @llvm.va_end(i8*)
5225</pre>
5226</div>
5227
5228</div>
5229
5230<!-- _______________________________________________________________________ -->
5231<div class="doc_subsubsection">
5232 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5233</div>
5234
5235
5236<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5238<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5239<pre>
5240 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5241</pre>
5242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5243<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5244<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5245 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]5246
5247<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5248<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]5249
5250<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5251<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]5252 macro available in C. In a target-dependent way, it initializes
5253 the <tt>va_list</tt> element to which the argument points, so that the next
5254 call to <tt>va_arg</tt> will produce the first variable argument passed to
5255 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5256 need to know the last argument of the function as the compiler can figure
5257 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5258
5259</div>
5260
5261<!-- _______________________________________________________________________ -->
5262<div class="doc_subsubsection">
5263 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5264</div>
5265
5266<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5267
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5268<h5>Syntax:</h5>
5269<pre>
5270 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5271</pre>
5272
5273<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5275 which has been initialized previously
5276 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5277 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5278
5279<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5280<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5281
5282<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5283<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]5284 macro available in C. In a target-dependent way, it destroys
5285 the <tt>va_list</tt> element to which the argument points. Calls
5286 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5287 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5288 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289
5290</div>
5291
5292<!-- _______________________________________________________________________ -->
5293<div class="doc_subsubsection">
5294 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5295</div>
5296
5297<div class="doc_text">
5298
5299<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5300<pre>
5301 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5302</pre>
5303
5304<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5305<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5306 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5307
5308<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5309<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]5310 The second argument is a pointer to a <tt>va_list</tt> element to copy
5311 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5312
5313<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5314<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]5315 macro available in C. In a target-dependent way, it copies the
5316 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5317 element. This intrinsic is necessary because
5318 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5319 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5320
5321</div>
5322
5323<!-- ======================================================================= -->
5324<div class="doc_subsection">
5325 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5326</div>
5327
5328<div class="doc_text">
5329
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5330<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5331Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5332intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5333roots on the stack</a>, as well as garbage collector implementations that
5334require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5335barriers. Front-ends for type-safe garbage collected languages should generate
5336these intrinsics to make use of the LLVM garbage collectors. For more details,
5337see <a href="GarbageCollection.html">Accurate Garbage Collection with
5338LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5339
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5340<p>The garbage collection intrinsics only operate on objects in the generic
5341 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5343</div>
5344
5345<!-- _______________________________________________________________________ -->
5346<div class="doc_subsubsection">
5347 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5348</div>
5349
5350<div class="doc_text">
5351
5352<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5353<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5354 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5355</pre>
5356
5357<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5358<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]5359 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5360
5361<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5362<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5363 root pointer. The second pointer (which must be either a constant or a
5364 global value address) contains the meta-data to be associated with the
5365 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5366
5367<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5368<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]5369 location. At compile-time, the code generator generates information to allow
5370 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5371 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5372 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5373
5374</div>
5375
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5376<!-- _______________________________________________________________________ -->
5377<div class="doc_subsubsection">
5378 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5379</div>
5380
5381<div class="doc_text">
5382
5383<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5385 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5386</pre>
5387
5388<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5389<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5390 locations, allowing garbage collector implementations that require read
5391 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5392
5393<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5394<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]5395 allocated from the garbage collector. The first object is a pointer to the
5396 start of the referenced object, if needed by the language runtime (otherwise
5397 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5398
5399<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5401 instruction, but may be replaced with substantially more complex code by the
5402 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5403 may only be used in a function which <a href="#gc">specifies a GC
5404 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5405
5406</div>
5407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5408<!-- _______________________________________________________________________ -->
5409<div class="doc_subsubsection">
5410 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5411</div>
5412
5413<div class="doc_text">
5414
5415<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5416<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5417 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5418</pre>
5419
5420<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5421<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5422 locations, allowing garbage collector implementations that require write
5423 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5424
5425<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5426<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]5427 object to store it to, and the third is the address of the field of Obj to
5428 store to. If the runtime does not require a pointer to the object, Obj may
5429 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5430
5431<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5432<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5433 instruction, but may be replaced with substantially more complex code by the
5434 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5435 may only be used in a function which <a href="#gc">specifies a GC
5436 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5437
5438</div>
5439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5440<!-- ======================================================================= -->
5441<div class="doc_subsection">
5442 <a name="int_codegen">Code Generator Intrinsics</a>
5443</div>
5444
5445<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5446
5447<p>These intrinsics are provided by LLVM to expose special features that may
5448 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449
5450</div>
5451
5452<!-- _______________________________________________________________________ -->
5453<div class="doc_subsubsection">
5454 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5455</div>
5456
5457<div class="doc_text">
5458
5459<h5>Syntax:</h5>
5460<pre>
5461 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5462</pre>
5463
5464<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5465<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5466 target-specific value indicating the return address of the current function
5467 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5468
5469<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5470<p>The argument to this intrinsic indicates which function to return the address
5471 for. Zero indicates the calling function, one indicates its caller, etc.
5472 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473
5474<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5475<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5476 indicating the return address of the specified call frame, or zero if it
5477 cannot be identified. The value returned by this intrinsic is likely to be
5478 incorrect or 0 for arguments other than zero, so it should only be used for
5479 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5480
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5481<p>Note that calling this intrinsic does not prevent function inlining or other
5482 aggressive transformations, so the value returned may not be that of the
5483 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5485</div>
5486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487<!-- _______________________________________________________________________ -->
5488<div class="doc_subsubsection">
5489 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5490</div>
5491
5492<div class="doc_text">
5493
5494<h5>Syntax:</h5>
5495<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5496 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5497</pre>
5498
5499<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5500<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5501 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5502
5503<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5504<p>The argument to this intrinsic indicates which function to return the frame
5505 pointer for. Zero indicates the calling function, one indicates its caller,
5506 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5507
5508<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5509<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5510 indicating the frame address of the specified call frame, or zero if it
5511 cannot be identified. The value returned by this intrinsic is likely to be
5512 incorrect or 0 for arguments other than zero, so it should only be used for
5513 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5515<p>Note that calling this intrinsic does not prevent function inlining or other
5516 aggressive transformations, so the value returned may not be that of the
5517 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519</div>
5520
5521<!-- _______________________________________________________________________ -->
5522<div class="doc_subsubsection">
5523 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5524</div>
5525
5526<div class="doc_text">
5527
5528<h5>Syntax:</h5>
5529<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5530 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5531</pre>
5532
5533<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5534<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5535 of the function stack, for use
5536 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5537 useful for implementing language features like scoped automatic variable
5538 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5539
5540<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5541<p>This intrinsic returns a opaque pointer value that can be passed
5542 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5543 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5544 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5545 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5546 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5547 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5548
5549</div>
5550
5551<!-- _______________________________________________________________________ -->
5552<div class="doc_subsubsection">
5553 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5554</div>
5555
5556<div class="doc_text">
5557
5558<h5>Syntax:</h5>
5559<pre>
5560 declare void @llvm.stackrestore(i8 * %ptr)
5561</pre>
5562
5563<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5564<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5565 the function stack to the state it was in when the
5566 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5567 executed. This is useful for implementing language features like scoped
5568 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5569
5570<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5571<p>See the description
5572 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5573
5574</div>
5575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5576<!-- _______________________________________________________________________ -->
5577<div class="doc_subsubsection">
5578 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5579</div>
5580
5581<div class="doc_text">
5582
5583<h5>Syntax:</h5>
5584<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5585 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]5586</pre>
5587
5588<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5589<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5590 insert a prefetch instruction if supported; otherwise, it is a noop.
5591 Prefetches have no effect on the behavior of the program but can change its
5592 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5593
5594<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5595<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5596 specifier determining if the fetch should be for a read (0) or write (1),
5597 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5598 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5599 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5600
5601<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5602<p>This intrinsic does not modify the behavior of the program. In particular,
5603 prefetches cannot trap and do not produce a value. On targets that support
5604 this intrinsic, the prefetch can provide hints to the processor cache for
5605 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5606
5607</div>
5608
5609<!-- _______________________________________________________________________ -->
5610<div class="doc_subsubsection">
5611 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5612</div>
5613
5614<div class="doc_text">
5615
5616<h5>Syntax:</h5>
5617<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5618 declare void @llvm.pcmarker(i32 &lt;id&gt;)
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.pcmarker</tt>' intrinsic is a method to export a Program
5623 Counter (PC) in a region of code to simulators and other tools. The method
5624 is target specific, but it is expected that the marker will use exported
5625 symbols to transmit the PC of the marker. The marker makes no guarantees
5626 that it will remain with any specific instruction after optimizations. It is
5627 possible that the presence of a marker will inhibit optimizations. The
5628 intended use is to be inserted after optimizations to allow correlations of
5629 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5630
5631<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5632<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5633
5634<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5635<p>This intrinsic does not modify the behavior of the program. Backends that do
5636 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5637
5638</div>
5639
5640<!-- _______________________________________________________________________ -->
5641<div class="doc_subsubsection">
5642 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5643</div>
5644
5645<div class="doc_text">
5646
5647<h5>Syntax:</h5>
5648<pre>
5649 declare i64 @llvm.readcyclecounter( )
5650</pre>
5651
5652<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5653<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5654 counter register (or similar low latency, high accuracy clocks) on those
5655 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5656 should map to RPCC. As the backing counters overflow quickly (on the order
5657 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5658
5659<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5660<p>When directly supported, reading the cycle counter should not modify any
5661 memory. Implementations are allowed to either return a application specific
5662 value or a system wide value. On backends without support, this is lowered
5663 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5664
5665</div>
5666
5667<!-- ======================================================================= -->
5668<div class="doc_subsection">
5669 <a name="int_libc">Standard C Library Intrinsics</a>
5670</div>
5671
5672<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5673
5674<p>LLVM provides intrinsics for a few important standard C library functions.
5675 These intrinsics allow source-language front-ends to pass information about
5676 the alignment of the pointer arguments to the code generator, providing
5677 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5678
5679</div>
5680
5681<!-- _______________________________________________________________________ -->
5682<div class="doc_subsubsection">
5683 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5684</div>
5685
5686<div class="doc_text">
5687
5688<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5689<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5690 integer bit width. Not all targets support all bit widths however.</p>
5691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5693 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5694 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5695 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5696 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5697 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5698 i32 &lt;len&gt;, i32 &lt;align&gt;)
5699 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5700 i64 &lt;len&gt;, i32 &lt;align&gt;)
5701</pre>
5702
5703<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5704<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5705 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5706
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5707<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5708 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5709
5710<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5711<p>The first argument is a pointer to the destination, the second is a pointer
5712 to the source. The third argument is an integer argument specifying the
5713 number of bytes to copy, and the fourth argument is the alignment of the
5714 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5715
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5716<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5717 then the caller guarantees that both the source and destination pointers are
5718 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5719
5720<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5721<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5722 source location to the destination location, which are not allowed to
5723 overlap. It copies "len" bytes of memory over. If the argument is known to
5724 be aligned to some boundary, this can be specified as the fourth argument,
5725 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5727</div>
5728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729<!-- _______________________________________________________________________ -->
5730<div class="doc_subsubsection">
5731 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5732</div>
5733
5734<div class="doc_text">
5735
5736<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5737<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]5738 width. Not all targets support all bit widths however.</p>
5739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5740<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5741 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5742 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5743 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5744 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5745 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5746 i32 &lt;len&gt;, i32 &lt;align&gt;)
5747 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5748 i64 &lt;len&gt;, i32 &lt;align&gt;)
5749</pre>
5750
5751<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5752<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5753 source location to the destination location. It is similar to the
5754 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5755 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5756
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5757<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5758 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5759
5760<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5761<p>The first argument is a pointer to the destination, the second is a pointer
5762 to the source. The third argument is an integer argument specifying the
5763 number of bytes to copy, and the fourth argument is the alignment of the
5764 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5765
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5766<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5767 then the caller guarantees that the source and destination pointers are
5768 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5769
5770<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5772 source location to the destination location, which may overlap. It copies
5773 "len" bytes of memory over. If the argument is known to be aligned to some
5774 boundary, this can be specified as the fourth argument, otherwise it should
5775 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777</div>
5778
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5779<!-- _______________________________________________________________________ -->
5780<div class="doc_subsubsection">
5781 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5782</div>
5783
5784<div class="doc_text">
5785
5786<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5787<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]5788 width. Not all targets support all bit widths however.</p>
5789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5790<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5791 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5792 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5793 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5794 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5795 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5796 i32 &lt;len&gt;, i32 &lt;align&gt;)
5797 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5798 i64 &lt;len&gt;, i32 &lt;align&gt;)
5799</pre>
5800
5801<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5802<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5803 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5805<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5806 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5807
5808<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5809<p>The first argument is a pointer to the destination to fill, the second is the
5810 byte value to fill it with, the third argument is an integer argument
5811 specifying the number of bytes to fill, and the fourth argument is the known
5812 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5813
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5814<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5815 then the caller guarantees that the destination pointer is aligned to that
5816 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5817
5818<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5820 at the destination location. If the argument is known to be aligned to some
5821 boundary, this can be specified as the fourth argument, otherwise it should
5822 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5823
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5824</div>
5825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
5828 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5834<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5835 floating point or vector of floating point type. Not all targets support all
5836 types however.</p>
5837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5838<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5839 declare float @llvm.sqrt.f32(float %Val)
5840 declare double @llvm.sqrt.f64(double %Val)
5841 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5842 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5843 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5847<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5848 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5849 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5850 behavior for negative numbers other than -0.0 (which allows for better
5851 optimization, because there is no need to worry about errno being
5852 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]5853
5854<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5855<p>The argument and return value are floating point numbers of the same
5856 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5857
5858<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5859<p>This function returns the sqrt of the specified operand if it is a
5860 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5862</div>
5863
5864<!-- _______________________________________________________________________ -->
5865<div class="doc_subsubsection">
5866 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5867</div>
5868
5869<div class="doc_text">
5870
5871<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5872<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5873 floating point or vector of floating point type. Not all targets support all
5874 types however.</p>
5875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5876<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5877 declare float @llvm.powi.f32(float %Val, i32 %power)
5878 declare double @llvm.powi.f64(double %Val, i32 %power)
5879 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5880 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5881 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5882</pre>
5883
5884<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5885<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5886 specified (positive or negative) power. The order of evaluation of
5887 multiplications is not defined. When a vector of floating point type is
5888 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5889
5890<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5891<p>The second argument is an integer power, and the first is a value to raise to
5892 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5893
5894<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5895<p>This function returns the first value raised to the second power with an
5896 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5898</div>
5899
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5900<!-- _______________________________________________________________________ -->
5901<div class="doc_subsubsection">
5902 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5903</div>
5904
5905<div class="doc_text">
5906
5907<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5908<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5909 floating point or vector of floating point type. Not all targets support all
5910 types however.</p>
5911
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5912<pre>
5913 declare float @llvm.sin.f32(float %Val)
5914 declare double @llvm.sin.f64(double %Val)
5915 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5916 declare fp128 @llvm.sin.f128(fp128 %Val)
5917 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5918</pre>
5919
5920<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5921<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5922
5923<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5924<p>The argument and return value are floating point numbers of the same
5925 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5926
5927<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5928<p>This function returns the sine of the specified operand, returning the same
5929 values as the libm <tt>sin</tt> functions would, and handles error conditions
5930 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5931
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5932</div>
5933
5934<!-- _______________________________________________________________________ -->
5935<div class="doc_subsubsection">
5936 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5937</div>
5938
5939<div class="doc_text">
5940
5941<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5942<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5943 floating point or vector of floating point type. Not all targets support all
5944 types however.</p>
5945
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5946<pre>
5947 declare float @llvm.cos.f32(float %Val)
5948 declare double @llvm.cos.f64(double %Val)
5949 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5950 declare fp128 @llvm.cos.f128(fp128 %Val)
5951 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5952</pre>
5953
5954<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5955<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5956
5957<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5958<p>The argument and return value are floating point numbers of the same
5959 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5960
5961<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5962<p>This function returns the cosine of the specified operand, returning the same
5963 values as the libm <tt>cos</tt> functions would, and handles error conditions
5964 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5965
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5966</div>
5967
5968<!-- _______________________________________________________________________ -->
5969<div class="doc_subsubsection">
5970 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5971</div>
5972
5973<div class="doc_text">
5974
5975<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5976<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5977 floating point or vector of floating point type. Not all targets support all
5978 types however.</p>
5979
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5980<pre>
5981 declare float @llvm.pow.f32(float %Val, float %Power)
5982 declare double @llvm.pow.f64(double %Val, double %Power)
5983 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5984 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5985 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5986</pre>
5987
5988<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5989<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5990 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5991
5992<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5993<p>The second argument is a floating point power, and the first is a value to
5994 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5995
5996<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5997<p>This function returns the first value raised to the second power, returning
5998 the same values as the libm <tt>pow</tt> functions would, and handles error
5999 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6000
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6001</div>
6002
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6003<!-- ======================================================================= -->
6004<div class="doc_subsection">
6005 <a name="int_manip">Bit Manipulation Intrinsics</a>
6006</div>
6007
6008<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6009
6010<p>LLVM provides intrinsics for a few important bit manipulation operations.
6011 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6012
6013</div>
6014
6015<!-- _______________________________________________________________________ -->
6016<div class="doc_subsubsection">
6017 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6018</div>
6019
6020<div class="doc_text">
6021
6022<h5>Syntax:</h5>
6023<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6024 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6026<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6027 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6028 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6029 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6030</pre>
6031
6032<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6033<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6034 values with an even number of bytes (positive multiple of 16 bits). These
6035 are useful for performing operations on data that is not in the target's
6036 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6037
6038<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6039<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6040 and low byte of the input i16 swapped. Similarly,
6041 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6042 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6043 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6044 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6045 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6046 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6047
6048</div>
6049
6050<!-- _______________________________________________________________________ -->
6051<div class="doc_subsubsection">
6052 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6053</div>
6054
6055<div class="doc_text">
6056
6057<h5>Syntax:</h5>
6058<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]6059 width. Not all targets support all bit widths however.</p>
6060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6061<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6062 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6063 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6064 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6065 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6066 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6067</pre>
6068
6069<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6070<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6071 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6072
6073<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6074<p>The only argument is the value to be counted. The argument may be of any
6075 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6076
6077<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6078<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]6079
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6080</div>
6081
6082<!-- _______________________________________________________________________ -->
6083<div class="doc_subsubsection">
6084 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6085</div>
6086
6087<div class="doc_text">
6088
6089<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6090<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6091 integer bit width. Not all targets support all bit widths however.</p>
6092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6093<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6094 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6095 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6096 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6097 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6098 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6099</pre>
6100
6101<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6102<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6103 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6104
6105<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6106<p>The only argument is the value to be counted. The argument may be of any
6107 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6108
6109<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6110<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6111 zeros in a variable. If the src == 0 then the result is the size in bits of
6112 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6114</div>
6115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6116<!-- _______________________________________________________________________ -->
6117<div class="doc_subsubsection">
6118 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6119</div>
6120
6121<div class="doc_text">
6122
6123<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6124<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6125 integer bit width. Not all targets support all bit widths however.</p>
6126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6127<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6128 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6129 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6130 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6131 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6132 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6133</pre>
6134
6135<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6136<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6137 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6138
6139<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6140<p>The only argument is the value to be counted. The argument may be of any
6141 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6142
6143<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6144<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6145 zeros in a variable. If the src == 0 then the result is the size in bits of
6146 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6147
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6148</div>
6149
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6150<!-- ======================================================================= -->
6151<div class="doc_subsection">
6152 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6153</div>
6154
6155<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6156
6157<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6158
6159</div>
6160
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6161<!-- _______________________________________________________________________ -->
6162<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6163 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6164</div>
6165
6166<div class="doc_text">
6167
6168<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6169<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]6170 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6171
6172<pre>
6173 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6174 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6175 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6176</pre>
6177
6178<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6179<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6180 a signed addition of the two arguments, and indicate whether an overflow
6181 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6182
6183<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6184<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]6185 be of integer types of any bit width, but they must have the same bit
6186 width. The second element of the result structure must be of
6187 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6188 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6189
6190<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6191<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6192 a signed addition of the two variables. They return a structure &mdash; the
6193 first element of which is the signed summation, and the second element of
6194 which is a bit specifying if the signed summation resulted in an
6195 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6196
6197<h5>Examples:</h5>
6198<pre>
6199 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6200 %sum = extractvalue {i32, i1} %res, 0
6201 %obit = extractvalue {i32, i1} %res, 1
6202 br i1 %obit, label %overflow, label %normal
6203</pre>
6204
6205</div>
6206
6207<!-- _______________________________________________________________________ -->
6208<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6209 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6210</div>
6211
6212<div class="doc_text">
6213
6214<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6215<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]6216 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6217
6218<pre>
6219 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6220 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6221 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6222</pre>
6223
6224<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6225<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6226 an unsigned addition of the two arguments, and indicate whether a carry
6227 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6228
6229<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6230<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]6231 be of integer types of any bit width, but they must have the same bit
6232 width. The second element of the result structure must be of
6233 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6234 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6235
6236<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6237<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6238 an unsigned addition of the two arguments. They return a structure &mdash;
6239 the first element of which is the sum, and the second element of which is a
6240 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6241
6242<h5>Examples:</h5>
6243<pre>
6244 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6245 %sum = extractvalue {i32, i1} %res, 0
6246 %obit = extractvalue {i32, i1} %res, 1
6247 br i1 %obit, label %carry, label %normal
6248</pre>
6249
6250</div>
6251
6252<!-- _______________________________________________________________________ -->
6253<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6254 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6255</div>
6256
6257<div class="doc_text">
6258
6259<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6260<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]6261 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6262
6263<pre>
6264 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6265 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6266 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6267</pre>
6268
6269<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6270<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6271 a signed subtraction of the two arguments, and indicate whether an overflow
6272 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6273
6274<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6275<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]6276 be of integer types of any bit width, but they must have the same bit
6277 width. The second element of the result structure must be of
6278 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6279 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6280
6281<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6282<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6283 a signed subtraction of the two arguments. They return a structure &mdash;
6284 the first element of which is the subtraction, and the second element of
6285 which is a bit specifying if the signed subtraction resulted in an
6286 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6287
6288<h5>Examples:</h5>
6289<pre>
6290 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6291 %sum = extractvalue {i32, i1} %res, 0
6292 %obit = extractvalue {i32, i1} %res, 1
6293 br i1 %obit, label %overflow, label %normal
6294</pre>
6295
6296</div>
6297
6298<!-- _______________________________________________________________________ -->
6299<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6300 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6301</div>
6302
6303<div class="doc_text">
6304
6305<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6306<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]6307 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6308
6309<pre>
6310 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6311 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6312 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6313</pre>
6314
6315<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6316<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6317 an unsigned subtraction of the two arguments, and indicate whether an
6318 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6319
6320<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6321<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]6322 be of integer types of any bit width, but they must have the same bit
6323 width. The second element of the result structure must be of
6324 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6325 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6326
6327<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6328<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6329 an unsigned subtraction of the two arguments. They return a structure &mdash;
6330 the first element of which is the subtraction, and the second element of
6331 which is a bit specifying if the unsigned subtraction resulted in an
6332 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6333
6334<h5>Examples:</h5>
6335<pre>
6336 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6337 %sum = extractvalue {i32, i1} %res, 0
6338 %obit = extractvalue {i32, i1} %res, 1
6339 br i1 %obit, label %overflow, label %normal
6340</pre>
6341
6342</div>
6343
6344<!-- _______________________________________________________________________ -->
6345<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6346 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6347</div>
6348
6349<div class="doc_text">
6350
6351<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6352<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]6353 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6354
6355<pre>
6356 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6357 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6358 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6359</pre>
6360
6361<h5>Overview:</h5>
6362
6363<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6364 a signed multiplication of the two arguments, and indicate whether an
6365 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6366
6367<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6368<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]6369 be of integer types of any bit width, but they must have the same bit
6370 width. The second element of the result structure must be of
6371 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6372 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6373
6374<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6375<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6376 a signed multiplication of the two arguments. They return a structure &mdash;
6377 the first element of which is the multiplication, and the second element of
6378 which is a bit specifying if the signed multiplication resulted in an
6379 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6380
6381<h5>Examples:</h5>
6382<pre>
6383 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6384 %sum = extractvalue {i32, i1} %res, 0
6385 %obit = extractvalue {i32, i1} %res, 1
6386 br i1 %obit, label %overflow, label %normal
6387</pre>
6388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6389</div>
6390
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6391<!-- _______________________________________________________________________ -->
6392<div class="doc_subsubsection">
6393 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6394</div>
6395
6396<div class="doc_text">
6397
6398<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6399<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]6400 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6401
6402<pre>
6403 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6404 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6405 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6406</pre>
6407
6408<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6409<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6410 a unsigned multiplication of the two arguments, and indicate whether an
6411 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6412
6413<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6414<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]6415 be of integer types of any bit width, but they must have the same bit
6416 width. The second element of the result structure must be of
6417 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6418 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6419
6420<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6421<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6422 an unsigned multiplication of the two arguments. They return a structure
6423 &mdash; the first element of which is the multiplication, and the second
6424 element of which is a bit specifying if the unsigned multiplication resulted
6425 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6426
6427<h5>Examples:</h5>
6428<pre>
6429 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6430 %sum = extractvalue {i32, i1} %res, 0
6431 %obit = extractvalue {i32, i1} %res, 1
6432 br i1 %obit, label %overflow, label %normal
6433</pre>
6434
6435</div>
6436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6437<!-- ======================================================================= -->
6438<div class="doc_subsection">
6439 <a name="int_debugger">Debugger Intrinsics</a>
6440</div>
6441
6442<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6443
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6444<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6445 prefix), are described in
6446 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6447 Level Debugging</a> document.</p>
6448
6449</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6450
6451<!-- ======================================================================= -->
6452<div class="doc_subsection">
6453 <a name="int_eh">Exception Handling Intrinsics</a>
6454</div>
6455
6456<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6457
6458<p>The LLVM exception handling intrinsics (which all start with
6459 <tt>llvm.eh.</tt> prefix), are described in
6460 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6461 Handling</a> document.</p>
6462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6463</div>
6464
6465<!-- ======================================================================= -->
6466<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6467 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6468</div>
6469
6470<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6471
6472<p>This intrinsic makes it possible to excise one parameter, marked with
6473 the <tt>nest</tt> attribute, from a function. The result is a callable
6474 function pointer lacking the nest parameter - the caller does not need to
6475 provide a value for it. Instead, the value to use is stored in advance in a
6476 "trampoline", a block of memory usually allocated on the stack, which also
6477 contains code to splice the nest value into the argument list. This is used
6478 to implement the GCC nested function address extension.</p>
6479
6480<p>For example, if the function is
6481 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6482 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6483 follows:</p>
6484
6485<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6486<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6487 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6488 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6489 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6490 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6491</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6492</div>
6493
6494<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6495 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6496
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6497</div>
6498
6499<!-- _______________________________________________________________________ -->
6500<div class="doc_subsubsection">
6501 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6502</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6503
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6504<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6505
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6506<h5>Syntax:</h5>
6507<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6508 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]6509</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6510
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6511<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6512<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6513 function pointer suitable for executing it.</p>
6514
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6515<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6516<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6517 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6518 sufficiently aligned block of memory; this memory is written to by the
6519 intrinsic. Note that the size and the alignment are target-specific - LLVM
6520 currently provides no portable way of determining them, so a front-end that
6521 generates this intrinsic needs to have some target-specific knowledge.
6522 The <tt>func</tt> argument must hold a function bitcast to
6523 an <tt>i8*</tt>.</p>
6524
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6525<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6526<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6527 dependent code, turning it into a function. A pointer to this function is
6528 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6529 function pointer type</a> before being called. The new function's signature
6530 is the same as that of <tt>func</tt> with any arguments marked with
6531 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6532 is allowed, and it must be of pointer type. Calling the new function is
6533 equivalent to calling <tt>func</tt> with the same argument list, but
6534 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6535 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6536 by <tt>tramp</tt> is modified, then the effect of any later call to the
6537 returned function pointer is undefined.</p>
6538
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6539</div>
6540
6541<!-- ======================================================================= -->
6542<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6543 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6544</div>
6545
6546<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6547
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6548<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6549 hardware constructs for atomic operations and memory synchronization. This
6550 provides an interface to the hardware, not an interface to the programmer. It
6551 is aimed at a low enough level to allow any programming models or APIs
6552 (Application Programming Interfaces) which need atomic behaviors to map
6553 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6554 hardware provides a "universal IR" for source languages, it also provides a
6555 starting point for developing a "universal" atomic operation and
6556 synchronization IR.</p>
6557
6558<p>These do <em>not</em> form an API such as high-level threading libraries,
6559 software transaction memory systems, atomic primitives, and intrinsic
6560 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6561 application libraries. The hardware interface provided by LLVM should allow
6562 a clean implementation of all of these APIs and parallel programming models.
6563 No one model or paradigm should be selected above others unless the hardware
6564 itself ubiquitously does so.</p>
6565
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6566</div>
6567
6568<!-- _______________________________________________________________________ -->
6569<div class="doc_subsubsection">
6570 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6571</div>
6572<div class="doc_text">
6573<h5>Syntax:</h5>
6574<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6575 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]6576</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6577
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6578<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6579<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6580 specific pairs of memory access types.</p>
6581
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6582<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6583<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6584 The first four arguments enables a specific barrier as listed below. The
6585 fith argument specifies that the barrier applies to io or device or uncached
6586 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6587
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6588<ul>
6589 <li><tt>ll</tt>: load-load barrier</li>
6590 <li><tt>ls</tt>: load-store barrier</li>
6591 <li><tt>sl</tt>: store-load barrier</li>
6592 <li><tt>ss</tt>: store-store barrier</li>
6593 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6594</ul>
6595
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6596<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6597<p>This intrinsic causes the system to enforce some ordering constraints upon
6598 the loads and stores of the program. This barrier does not
6599 indicate <em>when</em> any events will occur, it only enforces
6600 an <em>order</em> in which they occur. For any of the specified pairs of load
6601 and store operations (f.ex. load-load, or store-load), all of the first
6602 operations preceding the barrier will complete before any of the second
6603 operations succeeding the barrier begin. Specifically the semantics for each
6604 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6605
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6606<ul>
6607 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6608 after the barrier begins.</li>
6609 <li><tt>ls</tt>: All loads before the barrier must complete before any
6610 store after the barrier begins.</li>
6611 <li><tt>ss</tt>: All stores before the barrier must complete before any
6612 store after the barrier begins.</li>
6613 <li><tt>sl</tt>: All stores before the barrier must complete before any
6614 load after the barrier begins.</li>
6615</ul>
6616
6617<p>These semantics are applied with a logical "and" behavior when more than one
6618 is enabled in a single memory barrier intrinsic.</p>
6619
6620<p>Backends may implement stronger barriers than those requested when they do
6621 not support as fine grained a barrier as requested. Some architectures do
6622 not need all types of barriers and on such architectures, these become
6623 noops.</p>
6624
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6625<h5>Example:</h5>
6626<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6627%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6628%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6629 store i32 4, %ptr
6630
6631%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6632 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6633 <i>; guarantee the above finishes</i>
6634 store i32 8, %ptr <i>; before this begins</i>
6635</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6636
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6637</div>
6638
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6639<!-- _______________________________________________________________________ -->
6640<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6641 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6642</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6643
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6644<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6645
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6646<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6647<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6648 any integer bit width and for different address spaces. Not all targets
6649 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6650
6651<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6652 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6653 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6654 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6655 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]6656</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6657
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6658<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6659<p>This loads a value in memory and compares it to a given value. If they are
6660 equal, it stores a new value into the memory.</p>
6661
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6662<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6663<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6664 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6665 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6666 this integer type. While any bit width integer may be used, targets may only
6667 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6668
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6669<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6670<p>This entire intrinsic must be executed atomically. It first loads the value
6671 in memory pointed to by <tt>ptr</tt> and compares it with the
6672 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6673 memory. The loaded value is yielded in all cases. This provides the
6674 equivalent of an atomic compare-and-swap operation within the SSA
6675 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6676
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6677<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6678<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6679%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6680%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6681 store i32 4, %ptr
6682
6683%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6684%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6685 <i>; yields {i32}:result1 = 4</i>
6686%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6687%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6688
6689%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6690%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6691 <i>; yields {i32}:result2 = 8</i>
6692%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6693
6694%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6695</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6696
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6697</div>
6698
6699<!-- _______________________________________________________________________ -->
6700<div class="doc_subsubsection">
6701 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6702</div>
6703<div class="doc_text">
6704<h5>Syntax:</h5>
6705
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6706<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6707 integer bit width. Not all targets support all bit widths however.</p>
6708
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6709<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6710 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6711 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6712 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6713 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]6714</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6715
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6716<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6717<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6718 the value from memory. It then stores the value in <tt>val</tt> in the memory
6719 at <tt>ptr</tt>.</p>
6720
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6721<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6722<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6723 the <tt>val</tt> argument and the result must be integers of the same bit
6724 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6725 integer type. The targets may only lower integer representations they
6726 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6727
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6728<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6729<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6730 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6731 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6732
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6733<h5>Examples:</h5>
6734<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6735%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6736%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6737 store i32 4, %ptr
6738
6739%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6740%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6741 <i>; yields {i32}:result1 = 4</i>
6742%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6743%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6744
6745%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6746%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6747 <i>; yields {i32}:result2 = 8</i>
6748
6749%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6750%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6751</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6752
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6753</div>
6754
6755<!-- _______________________________________________________________________ -->
6756<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6757 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6758
6759</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6760
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6761<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6762
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6763<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6764<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6765 any integer bit width. Not all targets support all bit widths however.</p>
6766
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6767<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6768 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6769 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6770 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6771 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]6772</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6773
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6774<h5>Overview:</h5>
6775<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6776 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6777
6778<h5>Arguments:</h5>
6779<p>The intrinsic takes two arguments, the first a pointer to an integer value
6780 and the second an integer value. The result is also an integer value. These
6781 integer types can have any bit width, but they must all have the same bit
6782 width. The targets may only lower integer representations they support.</p>
6783
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6784<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6785<p>This intrinsic does a series of operations atomically. It first loads the
6786 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6787 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]6788
6789<h5>Examples:</h5>
6790<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6791%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6792%ptr = bitcast i8* %mallocP to i32*
6793 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6794%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6795 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6796%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6797 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6798%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6799 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6800%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6801</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6802
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6803</div>
6804
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6805<!-- _______________________________________________________________________ -->
6806<div class="doc_subsubsection">
6807 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6808
6809</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6810
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6811<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6812
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6813<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6814<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6815 any integer bit width and for different address spaces. Not all targets
6816 support all bit widths however.</p>
6817
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6818<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6819 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6820 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6821 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6822 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]6823</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6824
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6825<h5>Overview:</h5>
6826<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6827 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6828
6829<h5>Arguments:</h5>
6830<p>The intrinsic takes two arguments, the first a pointer to an integer value
6831 and the second an integer value. The result is also an integer value. These
6832 integer types can have any bit width, but they must all have the same bit
6833 width. The targets may only lower integer representations they support.</p>
6834
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6835<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6836<p>This intrinsic does a series of operations atomically. It first loads the
6837 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6838 result to <tt>ptr</tt>. It yields the original value stored
6839 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6840
6841<h5>Examples:</h5>
6842<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6843%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6844%ptr = bitcast i8* %mallocP to i32*
6845 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6846%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6847 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6848%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6849 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6850%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6851 <i>; yields {i32}:result3 = 2</i>
6852%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6853</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6854
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6855</div>
6856
6857<!-- _______________________________________________________________________ -->
6858<div class="doc_subsubsection">
6859 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6860 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6861 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6862 <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]6863</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6864
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6865<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6866
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6867<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6868<p>These are overloaded intrinsics. You can
6869 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6870 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6871 bit width and for different address spaces. Not all targets support all bit
6872 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6873
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6874<pre>
6875 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6876 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6877 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6878 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]6879</pre>
6880
6881<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6882 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6883 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6884 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6885 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]6886</pre>
6887
6888<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6889 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6890 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6891 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6892 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]6893</pre>
6894
6895<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6896 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6897 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6898 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6899 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]6900</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6901
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6902<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6903<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6904 the value stored in memory at <tt>ptr</tt>. It yields the original value
6905 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6906
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6907<h5>Arguments:</h5>
6908<p>These intrinsics take two arguments, the first a pointer to an integer value
6909 and the second an integer value. The result is also an integer value. These
6910 integer types can have any bit width, but they must all have the same bit
6911 width. The targets may only lower integer representations they support.</p>
6912
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6913<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6914<p>These intrinsics does a series of operations atomically. They first load the
6915 value stored at <tt>ptr</tt>. They then do the bitwise
6916 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6917 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6918
6919<h5>Examples:</h5>
6920<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6921%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6922%ptr = bitcast i8* %mallocP to i32*
6923 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6924%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6925 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6926%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6927 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6928%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6929 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6930%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6931 <i>; yields {i32}:result3 = FF</i>
6932%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6933</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6934
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6935</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6936
6937<!-- _______________________________________________________________________ -->
6938<div class="doc_subsubsection">
6939 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6940 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6941 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6942 <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]6943</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6944
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6945<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6946
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6947<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6948<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6949 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6950 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6951 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6952
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6953<pre>
6954 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6955 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6956 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6957 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]6958</pre>
6959
6960<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6961 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6962 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6963 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6964 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]6965</pre>
6966
6967<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6968 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6969 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6970 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6971 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]6972</pre>
6973
6974<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6975 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6976 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6977 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6978 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]6979</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6980
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6981<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6982<p>These intrinsics takes the signed or unsigned minimum or maximum of
6983 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6984 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6985
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6986<h5>Arguments:</h5>
6987<p>These intrinsics take two arguments, the first a pointer to an integer value
6988 and the second an integer value. The result is also an integer value. These
6989 integer types can have any bit width, but they must all have the same bit
6990 width. The targets may only lower integer representations they support.</p>
6991
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6992<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6993<p>These intrinsics does a series of operations atomically. They first load the
6994 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6995 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6996 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6997
6998<h5>Examples:</h5>
6999<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7000%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7001%ptr = bitcast i8* %mallocP to i32*
7002 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7003%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7004 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7005%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7006 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7007%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7008 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7009%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7010 <i>; yields {i32}:result3 = 8</i>
7011%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7012</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7013
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7014</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7015
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7016
7017<!-- ======================================================================= -->
7018<div class="doc_subsection">
7019 <a name="int_memorymarkers">Memory Use Markers</a>
7020</div>
7021
7022<div class="doc_text">
7023
7024<p>This class of intrinsics exists to information about the lifetime of memory
7025 objects and ranges where variables are immutable.</p>
7026
7027</div>
7028
7029<!-- _______________________________________________________________________ -->
7030<div class="doc_subsubsection">
7031 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7032</div>
7033
7034<div class="doc_text">
7035
7036<h5>Syntax:</h5>
7037<pre>
7038 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7039</pre>
7040
7041<h5>Overview:</h5>
7042<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7043 object's lifetime.</p>
7044
7045<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7046<p>The first argument is a constant integer representing the size of the
7047 object, or -1 if it is variable sized. The second argument is a pointer to
7048 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7049
7050<h5>Semantics:</h5>
7051<p>This intrinsic indicates that before this point in the code, the value of the
7052 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyf8a5f302009-10-27 16:56:58 +0000[diff] [blame]7053 never be used and has an undefined value. A load from the pointer that
7054 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7055 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7056
7057</div>
7058
7059<!-- _______________________________________________________________________ -->
7060<div class="doc_subsubsection">
7061 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7062</div>
7063
7064<div class="doc_text">
7065
7066<h5>Syntax:</h5>
7067<pre>
7068 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7069</pre>
7070
7071<h5>Overview:</h5>
7072<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7073 object's lifetime.</p>
7074
7075<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7076<p>The first argument is a constant integer representing the size of the
7077 object, or -1 if it is variable sized. The second argument is a pointer to
7078 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7079
7080<h5>Semantics:</h5>
7081<p>This intrinsic indicates that after this point in the code, the value of the
7082 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7083 never be used and has an undefined value. Any stores into the memory object
7084 following this intrinsic may be removed as dead.
7085
7086</div>
7087
7088<!-- _______________________________________________________________________ -->
7089<div class="doc_subsubsection">
7090 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7091</div>
7092
7093<div class="doc_text">
7094
7095<h5>Syntax:</h5>
7096<pre>
7097 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7098</pre>
7099
7100<h5>Overview:</h5>
7101<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7102 a memory object will not change.</p>
7103
7104<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7105<p>The first argument is a constant integer representing the size of the
7106 object, or -1 if it is variable sized. The second argument is a pointer to
7107 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7108
7109<h5>Semantics:</h5>
7110<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7111 the return value, the referenced memory location is constant and
7112 unchanging.</p>
7113
7114</div>
7115
7116<!-- _______________________________________________________________________ -->
7117<div class="doc_subsubsection">
7118 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7119</div>
7120
7121<div class="doc_text">
7122
7123<h5>Syntax:</h5>
7124<pre>
7125 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7126</pre>
7127
7128<h5>Overview:</h5>
7129<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7130 a memory object are mutable.</p>
7131
7132<h5>Arguments:</h5>
7133<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7134 The second argument is a constant integer representing the size of the
7135 object, or -1 if it is variable sized and the third argument is a pointer
7136 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7137
7138<h5>Semantics:</h5>
7139<p>This intrinsic indicates that the memory is mutable again.</p>
7140
7141</div>
7142
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7143<!-- ======================================================================= -->
7144<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7145 <a name="int_general">General Intrinsics</a>
7146</div>
7147
7148<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7149
7150<p>This class of intrinsics is designed to be generic and has no specific
7151 purpose.</p>
7152
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7153</div>
7154
7155<!-- _______________________________________________________________________ -->
7156<div class="doc_subsubsection">
7157 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7158</div>
7159
7160<div class="doc_text">
7161
7162<h5>Syntax:</h5>
7163<pre>
7164 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7165</pre>
7166
7167<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7168<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7169
7170<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7171<p>The first argument is a pointer to a value, the second is a pointer to a
7172 global string, the third is a pointer to a global string which is the source
7173 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7174
7175<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7176<p>This intrinsic allows annotation of local variables with arbitrary strings.
7177 This can be useful for special purpose optimizations that want to look for
7178 these annotations. These have no other defined use, they are ignored by code
7179 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7180
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7181</div>
7182
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7183<!-- _______________________________________________________________________ -->
7184<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7185 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7186</div>
7187
7188<div class="doc_text">
7189
7190<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7191<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7192 any integer bit width.</p>
7193
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7194<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7195 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7196 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7197 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7198 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7199 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]7200</pre>
7201
7202<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7203<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7204
7205<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7206<p>The first argument is an integer value (result of some expression), the
7207 second is a pointer to a global string, the third is a pointer to a global
7208 string which is the source file name, and the last argument is the line
7209 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7210
7211<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7212<p>This intrinsic allows annotations to be put on arbitrary expressions with
7213 arbitrary strings. This can be useful for special purpose optimizations that
7214 want to look for these annotations. These have no other defined use, they
7215 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7216
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7217</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7218
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7219<!-- _______________________________________________________________________ -->
7220<div class="doc_subsubsection">
7221 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7222</div>
7223
7224<div class="doc_text">
7225
7226<h5>Syntax:</h5>
7227<pre>
7228 declare void @llvm.trap()
7229</pre>
7230
7231<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7232<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7233
7234<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7235<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7236
7237<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7238<p>This intrinsics is lowered to the target dependent trap instruction. If the
7239 target does not have a trap instruction, this intrinsic will be lowered to
7240 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7241
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7242</div>
7243
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7244<!-- _______________________________________________________________________ -->
7245<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7246 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7247</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7248
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7249<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7250
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7251<h5>Syntax:</h5>
7252<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7253 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7254</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7255
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7256<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7257<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7258 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7259 ensure that it is placed on the stack before local variables.</p>
7260
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7261<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7262<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7263 arguments. The first argument is the value loaded from the stack
7264 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7265 that has enough space to hold the value of the guard.</p>
7266
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7267<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7268<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7269 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7270 stack. This is to ensure that if a local variable on the stack is
7271 overwritten, it will destroy the value of the guard. When the function exits,
7272 the guard on the stack is checked against the original guard. If they're
7273 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7274 function.</p>
7275
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7276</div>
7277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7278<!-- *********************************************************************** -->
7279<hr>
7280<address>
7281 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7282 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7283 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7284 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]7285
7286 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7287 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7288 Last modified: $Date$
7289</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7290
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7291</body>
7292</html>