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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 184f44df14e009fab8a3189b2b92e48e2a21398a / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]8 <meta name="description"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]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>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]57 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]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>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]294 <li><a href="#int_objectsize">
295 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]296 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]297 </li>
298 </ol>
299 </li>
300</ol>
301
302<div class="doc_author">
303 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
304 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
305</div>
306
307<!-- *********************************************************************** -->
308<div class="doc_section"> <a name="abstract">Abstract </a></div>
309<!-- *********************************************************************** -->
310
311<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]312
313<p>This document is a reference manual for the LLVM assembly language. LLVM is
314 a Static Single Assignment (SSA) based representation that provides type
315 safety, low-level operations, flexibility, and the capability of representing
316 'all' high-level languages cleanly. It is the common code representation
317 used throughout all phases of the LLVM compilation strategy.</p>
318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]319</div>
320
321<!-- *********************************************************************** -->
322<div class="doc_section"> <a name="introduction">Introduction</a> </div>
323<!-- *********************************************************************** -->
324
325<div class="doc_text">
326
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]327<p>The LLVM code representation is designed to be used in three different forms:
328 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
329 for fast loading by a Just-In-Time compiler), and as a human readable
330 assembly language representation. This allows LLVM to provide a powerful
331 intermediate representation for efficient compiler transformations and
332 analysis, while providing a natural means to debug and visualize the
333 transformations. The three different forms of LLVM are all equivalent. This
334 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]335
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]336<p>The LLVM representation aims to be light-weight and low-level while being
337 expressive, typed, and extensible at the same time. It aims to be a
338 "universal IR" of sorts, by being at a low enough level that high-level ideas
339 may be cleanly mapped to it (similar to how microprocessors are "universal
340 IR's", allowing many source languages to be mapped to them). By providing
341 type information, LLVM can be used as the target of optimizations: for
342 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]343 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]344 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]345
346</div>
347
348<!-- _______________________________________________________________________ -->
349<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
350
351<div class="doc_text">
352
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]353<p>It is important to note that this document describes 'well formed' LLVM
354 assembly language. There is a difference between what the parser accepts and
355 what is considered 'well formed'. For example, the following instruction is
356 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]357
358<div class="doc_code">
359<pre>
360%x = <a href="#i_add">add</a> i32 1, %x
361</pre>
362</div>
363
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]364<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
365 LLVM infrastructure provides a verification pass that may be used to verify
366 that an LLVM module is well formed. This pass is automatically run by the
367 parser after parsing input assembly and by the optimizer before it outputs
368 bitcode. The violations pointed out by the verifier pass indicate bugs in
369 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]371</div>
372
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]373<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]374
375<!-- *********************************************************************** -->
376<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
377<!-- *********************************************************************** -->
378
379<div class="doc_text">
380
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]381<p>LLVM identifiers come in two basic types: global and local. Global
382 identifiers (functions, global variables) begin with the <tt>'@'</tt>
383 character. Local identifiers (register names, types) begin with
384 the <tt>'%'</tt> character. Additionally, there are three different formats
385 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]386
387<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]388 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]389 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
390 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
391 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
392 other characters in their names can be surrounded with quotes. Special
393 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
394 ASCII code for the character in hexadecimal. In this way, any character
395 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]396
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]397 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]398 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]399
400 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]401 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]402</ol>
403
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]404<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]405 don't need to worry about name clashes with reserved words, and the set of
406 reserved words may be expanded in the future without penalty. Additionally,
407 unnamed identifiers allow a compiler to quickly come up with a temporary
408 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]409
410<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]411 languages. There are keywords for different opcodes
412 ('<tt><a href="#i_add">add</a></tt>',
413 '<tt><a href="#i_bitcast">bitcast</a></tt>',
414 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
415 ('<tt><a href="#t_void">void</a></tt>',
416 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
417 reserved words cannot conflict with variable names, because none of them
418 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]419
420<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]421 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]422
423<p>The easy way:</p>
424
425<div class="doc_code">
426<pre>
427%result = <a href="#i_mul">mul</a> i32 %X, 8
428</pre>
429</div>
430
431<p>After strength reduction:</p>
432
433<div class="doc_code">
434<pre>
435%result = <a href="#i_shl">shl</a> i32 %X, i8 3
436</pre>
437</div>
438
439<p>And the hard way:</p>
440
441<div class="doc_code">
442<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]443%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
444%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]445%result = <a href="#i_add">add</a> i32 %1, %1
446</pre>
447</div>
448
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]449<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
450 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]451
452<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]453 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]454 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]455
456 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]457 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458
459 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]460</ol>
461
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]462<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]463 demonstrating instructions, we will follow an instruction with a comment that
464 defines the type and name of value produced. Comments are shown in italic
465 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]466
467</div>
468
469<!-- *********************************************************************** -->
470<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
471<!-- *********************************************************************** -->
472
473<!-- ======================================================================= -->
474<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
475</div>
476
477<div class="doc_text">
478
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]479<p>LLVM programs are composed of "Module"s, each of which is a translation unit
480 of the input programs. Each module consists of functions, global variables,
481 and symbol table entries. Modules may be combined together with the LLVM
482 linker, which merges function (and global variable) definitions, resolves
483 forward declarations, and merges symbol table entries. Here is an example of
484 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]485
486<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]487<pre>
488<i>; Declare the string constant as a global constant.</i>
489<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]490
491<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]492<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]493
494<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]495define i32 @main() { <i>; i32()* </i>
496 <i>; Convert [13 x i8]* to i8 *...</i>
497 %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]498
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]499 <i>; Call puts function to write out the string to stdout.</i>
500 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
501 <a href="#i_ret">ret</a> i32 0<br>}<br>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]502</pre>
503</div>
504
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]505<p>This example is made up of a <a href="#globalvars">global variable</a> named
506 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
507 a <a href="#functionstructure">function definition</a> for
508 "<tt>main</tt>".</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]510<p>In general, a module is made up of a list of global values, where both
511 functions and global variables are global values. Global values are
512 represented by a pointer to a memory location (in this case, a pointer to an
513 array of char, and a pointer to a function), and have one of the
514 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]515
516</div>
517
518<!-- ======================================================================= -->
519<div class="doc_subsection">
520 <a name="linkage">Linkage Types</a>
521</div>
522
523<div class="doc_text">
524
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]525<p>All Global Variables and Functions have one of the following types of
526 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]527
528<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]529 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]530 <dd>Global values with private linkage are only directly accessible by objects
531 in the current module. In particular, linking code into a module with an
532 private global value may cause the private to be renamed as necessary to
533 avoid collisions. Because the symbol is private to the module, all
534 references can be updated. This doesn't show up in any symbol table in the
535 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]536
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]537 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]538 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]539 removed by the linker after evaluation. Note that (unlike private
540 symbols) linker_private symbols are subject to coalescing by the linker:
541 weak symbols get merged and redefinitions are rejected. However, unlike
542 normal strong symbols, they are removed by the linker from the final
543 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]544
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]545 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]546 <dd>Similar to private, but the value shows as a local symbol
547 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
548 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]549
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]550 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]551 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]552 into the object file corresponding to the LLVM module. They exist to
553 allow inlining and other optimizations to take place given knowledge of
554 the definition of the global, which is known to be somewhere outside the
555 module. Globals with <tt>available_externally</tt> linkage are allowed to
556 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
557 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]558
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]559 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]560 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]561 the same name when linkage occurs. This is typically used to implement
562 inline functions, templates, or other code which must be generated in each
563 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
564 allowed to be discarded.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]565
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]566 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]567 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
568 <tt>linkonce</tt> linkage, except that unreferenced globals with
569 <tt>weak</tt> linkage may not be discarded. This is used for globals that
570 are declared "weak" in C source code.</dd>
571
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]572 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]573 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
574 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
575 global scope.
576 Symbols with "<tt>common</tt>" linkage are merged in the same way as
577 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]578 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]579 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]580 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
581 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]583
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]584 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]585 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]586 pointer to array type. When two global variables with appending linkage
587 are linked together, the two global arrays are appended together. This is
588 the LLVM, typesafe, equivalent of having the system linker append together
589 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]590
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]591 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]592 <dd>The semantics of this linkage follow the ELF object file model: the symbol
593 is weak until linked, if not linked, the symbol becomes null instead of
594 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]595
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]596 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
597 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]598 <dd>Some languages allow differing globals to be merged, such as two functions
599 with different semantics. Other languages, such as <tt>C++</tt>, ensure
600 that only equivalent globals are ever merged (the "one definition rule" -
601 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
602 and <tt>weak_odr</tt> linkage types to indicate that the global will only
603 be merged with equivalent globals. These linkage types are otherwise the
604 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]607 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]608 visible, meaning that it participates in linkage and can be used to
609 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]610</dl>
611
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]612<p>The next two types of linkage are targeted for Microsoft Windows platform
613 only. They are designed to support importing (exporting) symbols from (to)
614 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]615
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]616<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]617 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]618 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]619 or variable via a global pointer to a pointer that is set up by the DLL
620 exporting the symbol. On Microsoft Windows targets, the pointer name is
621 formed by combining <code>__imp_</code> and the function or variable
622 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]624 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]625 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]626 pointer to a pointer in a DLL, so that it can be referenced with the
627 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
628 name is formed by combining <code>__imp_</code> and the function or
629 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]630</dl>
631
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]632<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
633 another module defined a "<tt>.LC0</tt>" variable and was linked with this
634 one, one of the two would be renamed, preventing a collision. Since
635 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
636 declarations), they are accessible outside of the current module.</p>
637
638<p>It is illegal for a function <i>declaration</i> to have any linkage type
639 other than "externally visible", <tt>dllimport</tt>
640 or <tt>extern_weak</tt>.</p>
641
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]642<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]643 or <tt>weak_odr</tt> linkages.</p>
644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]645</div>
646
647<!-- ======================================================================= -->
648<div class="doc_subsection">
649 <a name="callingconv">Calling Conventions</a>
650</div>
651
652<div class="doc_text">
653
654<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]655 and <a href="#i_invoke">invokes</a> can all have an optional calling
656 convention specified for the call. The calling convention of any pair of
657 dynamic caller/callee must match, or the behavior of the program is
658 undefined. The following calling conventions are supported by LLVM, and more
659 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]660
661<dl>
662 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]663 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]664 specified) matches the target C calling conventions. This calling
665 convention supports varargs function calls and tolerates some mismatch in
666 the declared prototype and implemented declaration of the function (as
667 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]668
669 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]670 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]671 (e.g. by passing things in registers). This calling convention allows the
672 target to use whatever tricks it wants to produce fast code for the
673 target, without having to conform to an externally specified ABI
674 (Application Binary Interface). Implementations of this convention should
675 allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
676 optimization</a> to be supported. This calling convention does not
677 support varargs and requires the prototype of all callees to exactly match
678 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]679
680 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]682 as possible under the assumption that the call is not commonly executed.
683 As such, these calls often preserve all registers so that the call does
684 not break any live ranges in the caller side. This calling convention
685 does not support varargs and requires the prototype of all callees to
686 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]687
688 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]689 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]690 target-specific calling conventions to be used. Target specific calling
691 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]692</dl>
693
694<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 support Pascal conventions or any other well-known target-independent
696 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]697
698</div>
699
700<!-- ======================================================================= -->
701<div class="doc_subsection">
702 <a name="visibility">Visibility Styles</a>
703</div>
704
705<div class="doc_text">
706
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]707<p>All Global Variables and Functions have one of the following visibility
708 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]709
710<dl>
711 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]712 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]713 that the declaration is visible to other modules and, in shared libraries,
714 means that the declared entity may be overridden. On Darwin, default
715 visibility means that the declaration is visible to other modules. Default
716 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]717
718 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]719 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]720 object if they are in the same shared object. Usually, hidden visibility
721 indicates that the symbol will not be placed into the dynamic symbol
722 table, so no other module (executable or shared library) can reference it
723 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]724
725 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]726 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]727 the dynamic symbol table, but that references within the defining module
728 will bind to the local symbol. That is, the symbol cannot be overridden by
729 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]730</dl>
731
732</div>
733
734<!-- ======================================================================= -->
735<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]736 <a name="namedtypes">Named Types</a>
737</div>
738
739<div class="doc_text">
740
741<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]742 it easier to read the IR and make the IR more condensed (particularly when
743 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]744
745<div class="doc_code">
746<pre>
747%mytype = type { %mytype*, i32 }
748</pre>
749</div>
750
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]751<p>You may give a name to any <a href="#typesystem">type</a> except
752 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
753 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]754
755<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]756 and that you can therefore specify multiple names for the same type. This
757 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
758 uses structural typing, the name is not part of the type. When printing out
759 LLVM IR, the printer will pick <em>one name</em> to render all types of a
760 particular shape. This means that if you have code where two different
761 source types end up having the same LLVM type, that the dumper will sometimes
762 print the "wrong" or unexpected type. This is an important design point and
763 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]764
765</div>
766
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]767<!-- ======================================================================= -->
768<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]769 <a name="globalvars">Global Variables</a>
770</div>
771
772<div class="doc_text">
773
774<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]775 instead of run-time. Global variables may optionally be initialized, may
776 have an explicit section to be placed in, and may have an optional explicit
777 alignment specified. A variable may be defined as "thread_local", which
778 means that it will not be shared by threads (each thread will have a
779 separated copy of the variable). A variable may be defined as a global
780 "constant," which indicates that the contents of the variable
781 will <b>never</b> be modified (enabling better optimization, allowing the
782 global data to be placed in the read-only section of an executable, etc).
783 Note that variables that need runtime initialization cannot be marked
784 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]786<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
787 constant, even if the final definition of the global is not. This capability
788 can be used to enable slightly better optimization of the program, but
789 requires the language definition to guarantee that optimizations based on the
790 'constantness' are valid for the translation units that do not include the
791 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]792
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]793<p>As SSA values, global variables define pointer values that are in scope
794 (i.e. they dominate) all basic blocks in the program. Global variables
795 always define a pointer to their "content" type because they describe a
796 region of memory, and all memory objects in LLVM are accessed through
797 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]798
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]799<p>A global variable may be declared to reside in a target-specific numbered
800 address space. For targets that support them, address spaces may affect how
801 optimizations are performed and/or what target instructions are used to
802 access the variable. The default address space is zero. The address space
803 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]805<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]806 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]807
808<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]809 the alignment is set to zero, the alignment of the global is set by the
810 target to whatever it feels convenient. If an explicit alignment is
811 specified, the global is forced to have at least that much alignment. All
812 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]814<p>For example, the following defines a global in a numbered address space with
815 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]816
817<div class="doc_code">
818<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]819@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]820</pre>
821</div>
822
823</div>
824
825
826<!-- ======================================================================= -->
827<div class="doc_subsection">
828 <a name="functionstructure">Functions</a>
829</div>
830
831<div class="doc_text">
832
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]833<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
834 optional <a href="#linkage">linkage type</a>, an optional
835 <a href="#visibility">visibility style</a>, an optional
836 <a href="#callingconv">calling convention</a>, a return type, an optional
837 <a href="#paramattrs">parameter attribute</a> for the return type, a function
838 name, a (possibly empty) argument list (each with optional
839 <a href="#paramattrs">parameter attributes</a>), optional
840 <a href="#fnattrs">function attributes</a>, an optional section, an optional
841 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
842 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]843
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]844<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
845 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]846 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]847 <a href="#callingconv">calling convention</a>, a return type, an optional
848 <a href="#paramattrs">parameter attribute</a> for the return type, a function
849 name, a possibly empty list of arguments, an optional alignment, and an
850 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]851
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]852<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]853 (Control Flow Graph) for the function. Each basic block may optionally start
854 with a label (giving the basic block a symbol table entry), contains a list
855 of instructions, and ends with a <a href="#terminators">terminator</a>
856 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]857
858<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]859 executed on entrance to the function, and it is not allowed to have
860 predecessor basic blocks (i.e. there can not be any branches to the entry
861 block of a function). Because the block can have no predecessors, it also
862 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]863
864<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]865 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]866
867<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]868 the alignment is set to zero, the alignment of the function is set by the
869 target to whatever it feels convenient. If an explicit alignment is
870 specified, the function is forced to have at least that much alignment. All
871 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]872
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]873<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]874<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]875<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]876define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]877 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
878 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
879 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
880 [<a href="#gc">gc</a>] { ... }
881</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]882</div>
883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884</div>
885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]886<!-- ======================================================================= -->
887<div class="doc_subsection">
888 <a name="aliasstructure">Aliases</a>
889</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]892
893<p>Aliases act as "second name" for the aliasee value (which can be either
894 function, global variable, another alias or bitcast of global value). Aliases
895 may have an optional <a href="#linkage">linkage type</a>, and an
896 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]897
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]898<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]899<div class="doc_code">
900<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]901@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902</pre>
903</div>
904
905</div>
906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]907<!-- ======================================================================= -->
908<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]909
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]910<div class="doc_text">
911
912<p>The return type and each parameter of a function type may have a set of
913 <i>parameter attributes</i> associated with them. Parameter attributes are
914 used to communicate additional information about the result or parameters of
915 a function. Parameter attributes are considered to be part of the function,
916 not of the function type, so functions with different parameter attributes
917 can have the same function type.</p>
918
919<p>Parameter attributes are simple keywords that follow the type specified. If
920 multiple parameter attributes are needed, they are space separated. For
921 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]922
923<div class="doc_code">
924<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]925declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]926declare i32 @atoi(i8 zeroext)
927declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]928</pre>
929</div>
930
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]931<p>Note that any attributes for the function result (<tt>nounwind</tt>,
932 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]933
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]934<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]935
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]936<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]937 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]938 <dd>This indicates to the code generator that the parameter or return value
939 should be zero-extended to a 32-bit value by the caller (for a parameter)
940 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]941
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]942 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]943 <dd>This indicates to the code generator that the parameter or return value
944 should be sign-extended to a 32-bit value by the caller (for a parameter)
945 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]946
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]947 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]948 <dd>This indicates that this parameter or return value should be treated in a
949 special target-dependent fashion during while emitting code for a function
950 call or return (usually, by putting it in a register as opposed to memory,
951 though some targets use it to distinguish between two different kinds of
952 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]953
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]954 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]955 <dd>This indicates that the pointer parameter should really be passed by value
956 to the function. The attribute implies that a hidden copy of the pointee
957 is made between the caller and the callee, so the callee is unable to
958 modify the value in the callee. This attribute is only valid on LLVM
959 pointer arguments. It is generally used to pass structs and arrays by
960 value, but is also valid on pointers to scalars. The copy is considered
961 to belong to the caller not the callee (for example,
962 <tt><a href="#readonly">readonly</a></tt> functions should not write to
963 <tt>byval</tt> parameters). This is not a valid attribute for return
964 values. The byval attribute also supports specifying an alignment with
965 the align attribute. This has a target-specific effect on the code
966 generator that usually indicates a desired alignment for the synthesized
967 stack slot.</dd>
968
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]969 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]970 <dd>This indicates that the pointer parameter specifies the address of a
971 structure that is the return value of the function in the source program.
972 This pointer must be guaranteed by the caller to be valid: loads and
973 stores to the structure may be assumed by the callee to not to trap. This
974 may only be applied to the first parameter. This is not a valid attribute
975 for return values. </dd>
976
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]977 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]978 <dd>This indicates that the pointer does not alias any global or any other
979 parameter. The caller is responsible for ensuring that this is the
980 case. On a function return value, <tt>noalias</tt> additionally indicates
981 that the pointer does not alias any other pointers visible to the
982 caller. For further details, please see the discussion of the NoAlias
983 response in
984 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
985 analysis</a>.</dd>
986
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]987 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]988 <dd>This indicates that the callee does not make any copies of the pointer
989 that outlive the callee itself. This is not a valid attribute for return
990 values.</dd>
991
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]992 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]993 <dd>This indicates that the pointer parameter can be excised using the
994 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
995 attribute for return values.</dd>
996</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]997
998</div>
999
1000<!-- ======================================================================= -->
1001<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1002 <a name="gc">Garbage Collector Names</a>
1003</div>
1004
1005<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1006
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1007<p>Each function may specify a garbage collector name, which is simply a
1008 string:</p>
1009
1010<div class="doc_code">
1011<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1012define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1013</pre>
1014</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1015
1016<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1017 collector which will cause the compiler to alter its output in order to
1018 support the named garbage collection algorithm.</p>
1019
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1020</div>
1021
1022<!-- ======================================================================= -->
1023<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1024 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1025</div>
1026
1027<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1028
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1029<p>Function attributes are set to communicate additional information about a
1030 function. Function attributes are considered to be part of the function, not
1031 of the function type, so functions with different parameter attributes can
1032 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1033
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1034<p>Function attributes are simple keywords that follow the type specified. If
1035 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1036
1037<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1038<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1039define void @f() noinline { ... }
1040define void @f() alwaysinline { ... }
1041define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1042define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1043</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1044</div>
1045
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1046<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1047 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1048 <dd>This attribute indicates that the inliner should attempt to inline this
1049 function into callers whenever possible, ignoring any active inlining size
1050 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1051
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1052 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1053 <dd>This attribute indicates that the source code contained a hint that inlining
1054 this function is desirable (such as the "inline" keyword in C/C++). It
1055 is just a hint; it imposes no requirements on the inliner.</dd>
1056
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1057 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1058 <dd>This attribute indicates that the inliner should never inline this
1059 function in any situation. This attribute may not be used together with
1060 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1061
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1062 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1063 <dd>This attribute suggests that optimization passes and code generator passes
1064 make choices that keep the code size of this function low, and otherwise
1065 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1066
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1067 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068 <dd>This function attribute indicates that the function never returns
1069 normally. This produces undefined behavior at runtime if the function
1070 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1071
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1072 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1073 <dd>This function attribute indicates that the function never returns with an
1074 unwind or exceptional control flow. If the function does unwind, its
1075 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1076
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1077 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1078 <dd>This attribute indicates that the function computes its result (or decides
1079 to unwind an exception) based strictly on its arguments, without
1080 dereferencing any pointer arguments or otherwise accessing any mutable
1081 state (e.g. memory, control registers, etc) visible to caller functions.
1082 It does not write through any pointer arguments
1083 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1084 changes any state visible to callers. This means that it cannot unwind
1085 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1086 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1087
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1088 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1089 <dd>This attribute indicates that the function does not write through any
1090 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1091 arguments) or otherwise modify any state (e.g. memory, control registers,
1092 etc) visible to caller functions. It may dereference pointer arguments
1093 and read state that may be set in the caller. A readonly function always
1094 returns the same value (or unwinds an exception identically) when called
1095 with the same set of arguments and global state. It cannot unwind an
1096 exception by calling the <tt>C++</tt> exception throwing methods, but may
1097 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1098
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1099 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1100 <dd>This attribute indicates that the function should emit a stack smashing
1101 protector. It is in the form of a "canary"&mdash;a random value placed on
1102 the stack before the local variables that's checked upon return from the
1103 function to see if it has been overwritten. A heuristic is used to
1104 determine if a function needs stack protectors or not.<br>
1105<br>
1106 If a function that has an <tt>ssp</tt> attribute is inlined into a
1107 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1108 function will have an <tt>ssp</tt> attribute.</dd>
1109
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1110 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1111 <dd>This attribute indicates that the function should <em>always</em> emit a
1112 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1113 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1114<br>
1115 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1116 function that doesn't have an <tt>sspreq</tt> attribute or which has
1117 an <tt>ssp</tt> attribute, then the resulting function will have
1118 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1119
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1120 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1121 <dd>This attribute indicates that the code generator should not use a red
1122 zone, even if the target-specific ABI normally permits it.</dd>
1123
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1124 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1125 <dd>This attributes disables implicit floating point instructions.</dd>
1126
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1127 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1128 <dd>This attribute disables prologue / epilogue emission for the function.
1129 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1130</dl>
1131
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1132</div>
1133
1134<!-- ======================================================================= -->
1135<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1136 <a name="moduleasm">Module-Level Inline Assembly</a>
1137</div>
1138
1139<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1140
1141<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1142 the GCC "file scope inline asm" blocks. These blocks are internally
1143 concatenated by LLVM and treated as a single unit, but may be separated in
1144 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1145
1146<div class="doc_code">
1147<pre>
1148module asm "inline asm code goes here"
1149module asm "more can go here"
1150</pre>
1151</div>
1152
1153<p>The strings can contain any character by escaping non-printable characters.
1154 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]1155 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1156
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1157<p>The inline asm code is simply printed to the machine code .s file when
1158 assembly code is generated.</p>
1159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1160</div>
1161
1162<!-- ======================================================================= -->
1163<div class="doc_subsection">
1164 <a name="datalayout">Data Layout</a>
1165</div>
1166
1167<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1169<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1170 data is to be laid out in memory. The syntax for the data layout is
1171 simply:</p>
1172
1173<div class="doc_code">
1174<pre>
1175target datalayout = "<i>layout specification</i>"
1176</pre>
1177</div>
1178
1179<p>The <i>layout specification</i> consists of a list of specifications
1180 separated by the minus sign character ('-'). Each specification starts with
1181 a letter and may include other information after the letter to define some
1182 aspect of the data layout. The specifications accepted are as follows:</p>
1183
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1184<dl>
1185 <dt><tt>E</tt></dt>
1186 <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]1187 bits with the most significance have the lowest address location.</dd>
1188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1190 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1191 the bits with the least significance have the lowest address
1192 location.</dd>
1193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1194 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1195 <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]1196 <i>preferred</i> alignments. All sizes are in bits. Specifying
1197 the <i>pref</i> alignment is optional. If omitted, the
1198 preceding <tt>:</tt> should be omitted too.</dd>
1199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1200 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1201 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1202 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1204 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1205 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1206 <i>size</i>.</dd>
1207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1208 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1209 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1210 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1211 (double).</dd>
1212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1213 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1214 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1215 <i>size</i>.</dd>
1216
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1217 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1218 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1219 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1220
1221 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1222 <dd>This specifies a set of native integer widths for the target CPU
1223 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1224 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1225 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1226 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1229<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1230 default set of specifications which are then (possibly) overriden by the
1231 specifications in the <tt>datalayout</tt> keyword. The default specifications
1232 are given in this list:</p>
1233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1234<ul>
1235 <li><tt>E</tt> - big endian</li>
1236 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1237 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1238 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1239 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1240 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1241 <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]1242 alignment of 64-bits</li>
1243 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1244 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1245 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1246 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1247 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1248 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1249</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1250
1251<p>When LLVM is determining the alignment for a given type, it uses the
1252 following rules:</p>
1253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1254<ol>
1255 <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]1256 specification is used.</li>
1257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258 <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]1259 smallest integer type that is larger than the bitwidth of the sought type
1260 is used. If none of the specifications are larger than the bitwidth then
1261 the the largest integer type is used. For example, given the default
1262 specifications above, the i7 type will use the alignment of i8 (next
1263 largest) while both i65 and i256 will use the alignment of i64 (largest
1264 specified).</li>
1265
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1266 <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]1267 largest vector type that is smaller than the sought vector type will be
1268 used as a fall back. This happens because &lt;128 x double&gt; can be
1269 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1270</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1272</div>
1273
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1274<!-- ======================================================================= -->
1275<div class="doc_subsection">
1276 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1277</div>
1278
1279<div class="doc_text">
1280
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1281<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1282with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1283is undefined. Pointer values are associated with address ranges
1284according to the following rules:</p>
1285
1286<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1287 <li>A pointer value formed from a
1288 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1289 is associated with the addresses associated with the first operand
1290 of the <tt>getelementptr</tt>.</li>
1291 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1292 range of the variable's storage.</li>
1293 <li>The result value of an allocation instruction is associated with
1294 the address range of the allocated storage.</li>
1295 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1296 no address.</li>
1297 <li>A pointer value formed by an
1298 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1299 address ranges of all pointer values that contribute (directly or
1300 indirectly) to the computation of the pointer's value.</li>
1301 <li>The result value of a
1302 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1303 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1304 <li>An integer constant other than zero or a pointer value returned
1305 from a function not defined within LLVM may be associated with address
1306 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1307 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1308 allocated by mechanisms provided by LLVM.</li>
1309 </ul>
1310
1311<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1312<tt><a href="#i_load">load</a></tt> merely indicates the size and
1313alignment of the memory from which to load, as well as the
1314interpretation of the value. The first operand of a
1315<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1316and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1317
1318<p>Consequently, type-based alias analysis, aka TBAA, aka
1319<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1320LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1321additional information which specialized optimization passes may use
1322to implement type-based alias analysis.</p>
1323
1324</div>
1325
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1326<!-- *********************************************************************** -->
1327<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1328<!-- *********************************************************************** -->
1329
1330<div class="doc_text">
1331
1332<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1333 intermediate representation. Being typed enables a number of optimizations
1334 to be performed on the intermediate representation directly, without having
1335 to do extra analyses on the side before the transformation. A strong type
1336 system makes it easier to read the generated code and enables novel analyses
1337 and transformations that are not feasible to perform on normal three address
1338 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1339
1340</div>
1341
1342<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1343<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1344Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1345
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1346<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1347
1348<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1349
1350<table border="1" cellspacing="0" cellpadding="4">
1351 <tbody>
1352 <tr><th>Classification</th><th>Types</th></tr>
1353 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1354 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1355 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1356 </tr>
1357 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1358 <td><a href="#t_floating">floating point</a></td>
1359 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1360 </tr>
1361 <tr>
1362 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1363 <td><a href="#t_integer">integer</a>,
1364 <a href="#t_floating">floating point</a>,
1365 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1366 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1367 <a href="#t_struct">structure</a>,
1368 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1369 <a href="#t_label">label</a>,
1370 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1371 </td>
1372 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1373 <tr>
1374 <td><a href="#t_primitive">primitive</a></td>
1375 <td><a href="#t_label">label</a>,
1376 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1377 <a href="#t_floating">floating point</a>,
1378 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1379 </tr>
1380 <tr>
1381 <td><a href="#t_derived">derived</a></td>
1382 <td><a href="#t_integer">integer</a>,
1383 <a href="#t_array">array</a>,
1384 <a href="#t_function">function</a>,
1385 <a href="#t_pointer">pointer</a>,
1386 <a href="#t_struct">structure</a>,
1387 <a href="#t_pstruct">packed structure</a>,
1388 <a href="#t_vector">vector</a>,
1389 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1390 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1391 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1392 </tbody>
1393</table>
1394
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1395<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1396 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1397 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1399</div>
1400
1401<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1402<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1403
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1404<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1405
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1406<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1407 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1408
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1409</div>
1410
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1411<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1412<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1413
1414<div class="doc_text">
1415
1416<h5>Overview:</h5>
1417<p>The integer type is a very simple type that simply specifies an arbitrary
1418 bit width for the integer type desired. Any bit width from 1 bit to
1419 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1420
1421<h5>Syntax:</h5>
1422<pre>
1423 iN
1424</pre>
1425
1426<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1427 value.</p>
1428
1429<h5>Examples:</h5>
1430<table class="layout">
1431 <tr class="layout">
1432 <td class="left"><tt>i1</tt></td>
1433 <td class="left">a single-bit integer.</td>
1434 </tr>
1435 <tr class="layout">
1436 <td class="left"><tt>i32</tt></td>
1437 <td class="left">a 32-bit integer.</td>
1438 </tr>
1439 <tr class="layout">
1440 <td class="left"><tt>i1942652</tt></td>
1441 <td class="left">a really big integer of over 1 million bits.</td>
1442 </tr>
1443</table>
1444
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1445</div>
1446
1447<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1448<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1449
1450<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1451
1452<table>
1453 <tbody>
1454 <tr><th>Type</th><th>Description</th></tr>
1455 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1456 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1457 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1458 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1459 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1460 </tbody>
1461</table>
1462
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1463</div>
1464
1465<!-- _______________________________________________________________________ -->
1466<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1467
1468<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1469
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1470<h5>Overview:</h5>
1471<p>The void type does not represent any value and has no size.</p>
1472
1473<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1474<pre>
1475 void
1476</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1477
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1478</div>
1479
1480<!-- _______________________________________________________________________ -->
1481<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1482
1483<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1484
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1485<h5>Overview:</h5>
1486<p>The label type represents code labels.</p>
1487
1488<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1489<pre>
1490 label
1491</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1492
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1493</div>
1494
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1495<!-- _______________________________________________________________________ -->
1496<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1497
1498<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1499
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1500<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1501<p>The metadata type represents embedded metadata. No derived types may be
1502 created from metadata except for <a href="#t_function">function</a>
1503 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1504
1505<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1506<pre>
1507 metadata
1508</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1509
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1510</div>
1511
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1512
1513<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1514<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1515
1516<div class="doc_text">
1517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1518<p>The real power in LLVM comes from the derived types in the system. This is
1519 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1520 useful types. Each of these types contain one or more element types which
1521 may be a primitive type, or another derived type. For example, it is
1522 possible to have a two dimensional array, using an array as the element type
1523 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1525</div>
1526
1527<!-- _______________________________________________________________________ -->
1528<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1529
1530<div class="doc_text">
1531
1532<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1533<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1534 sequentially in memory. The array type requires a size (number of elements)
1535 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1536
1537<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1538<pre>
1539 [&lt;# elements&gt; x &lt;elementtype&gt;]
1540</pre>
1541
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1542<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1543 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1544
1545<h5>Examples:</h5>
1546<table class="layout">
1547 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1548 <td class="left"><tt>[40 x i32]</tt></td>
1549 <td class="left">Array of 40 32-bit integer values.</td>
1550 </tr>
1551 <tr class="layout">
1552 <td class="left"><tt>[41 x i32]</tt></td>
1553 <td class="left">Array of 41 32-bit integer values.</td>
1554 </tr>
1555 <tr class="layout">
1556 <td class="left"><tt>[4 x i8]</tt></td>
1557 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1558 </tr>
1559</table>
1560<p>Here are some examples of multidimensional arrays:</p>
1561<table class="layout">
1562 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1563 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1564 <td class="left">3x4 array of 32-bit integer values.</td>
1565 </tr>
1566 <tr class="layout">
1567 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1568 <td class="left">12x10 array of single precision floating point values.</td>
1569 </tr>
1570 <tr class="layout">
1571 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1572 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1573 </tr>
1574</table>
1575
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1576<p>There is no restriction on indexing beyond the end of the array implied by
1577 a static type (though there are restrictions on indexing beyond the bounds
1578 of an allocated object in some cases). This means that single-dimension
1579 'variable sized array' addressing can be implemented in LLVM with a zero
1580 length array type. An implementation of 'pascal style arrays' in LLVM could
1581 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1582
1583</div>
1584
1585<!-- _______________________________________________________________________ -->
1586<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1588<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1590<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1591<p>The function type can be thought of as a function signature. It consists of
1592 a return type and a list of formal parameter types. The return type of a
1593 function type is a scalar type, a void type, or a struct type. If the return
1594 type is a struct type then all struct elements must be of first class types,
1595 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1597<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1598<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1599 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1600</pre>
1601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1602<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]1603 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1604 which indicates that the function takes a variable number of arguments.
1605 Variable argument functions can access their arguments with
1606 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1607 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1608 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1610<h5>Examples:</h5>
1611<table class="layout">
1612 <tr class="layout">
1613 <td class="left"><tt>i32 (i32)</tt></td>
1614 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1615 </td>
1616 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1617 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1618 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1619 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1620 an <tt>i16</tt> that should be sign extended and a
1621 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1622 <tt>float</tt>.
1623 </td>
1624 </tr><tr class="layout">
1625 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1626 <td class="left">A vararg function that takes at least one
1627 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1628 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1629 LLVM.
1630 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1631 </tr><tr class="layout">
1632 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1633 <td class="left">A function taking an <tt>i32</tt>, returning a
1634 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1635 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1636 </tr>
1637</table>
1638
1639</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1641<!-- _______________________________________________________________________ -->
1642<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1646<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1647<p>The structure type is used to represent a collection of data members together
1648 in memory. The packing of the field types is defined to match the ABI of the
1649 underlying processor. The elements of a structure may be any type that has a
1650 size.</p>
1651
1652<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1653 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1654 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1656<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1657<pre>
1658 { &lt;type list&gt; }
1659</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1661<h5>Examples:</h5>
1662<table class="layout">
1663 <tr class="layout">
1664 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1665 <td class="left">A triple of three <tt>i32</tt> values</td>
1666 </tr><tr class="layout">
1667 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1668 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1669 second element is a <a href="#t_pointer">pointer</a> to a
1670 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1671 an <tt>i32</tt>.</td>
1672 </tr>
1673</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1675</div>
1676
1677<!-- _______________________________________________________________________ -->
1678<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1679</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1680
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1681<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1683<h5>Overview:</h5>
1684<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1685 together in memory. There is no padding between fields. Further, the
1686 alignment of a packed structure is 1 byte. The elements of a packed
1687 structure may be any type that has a size.</p>
1688
1689<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1690 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1691 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
1692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1693<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1694<pre>
1695 &lt; { &lt;type list&gt; } &gt;
1696</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1698<h5>Examples:</h5>
1699<table class="layout">
1700 <tr class="layout">
1701 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1702 <td class="left">A triple of three <tt>i32</tt> values</td>
1703 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1704 <td class="left">
1705<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1706 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1707 second element is a <a href="#t_pointer">pointer</a> to a
1708 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1709 an <tt>i32</tt>.</td>
1710 </tr>
1711</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1713</div>
1714
1715<!-- _______________________________________________________________________ -->
1716<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1717
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1718<div class="doc_text">
1719
1720<h5>Overview:</h5>
1721<p>As in many languages, the pointer type represents a pointer or reference to
1722 another object, which must live in memory. Pointer types may have an optional
1723 address space attribute defining the target-specific numbered address space
1724 where the pointed-to object resides. The default address space is zero.</p>
1725
1726<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1727 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1729<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1730<pre>
1731 &lt;type&gt; *
1732</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1734<h5>Examples:</h5>
1735<table class="layout">
1736 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1737 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1738 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1739 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1740 </tr>
1741 <tr class="layout">
1742 <td class="left"><tt>i32 (i32 *) *</tt></td>
1743 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1744 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1745 <tt>i32</tt>.</td>
1746 </tr>
1747 <tr class="layout">
1748 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1749 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1750 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1751 </tr>
1752</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1754</div>
1755
1756<!-- _______________________________________________________________________ -->
1757<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1759<div class="doc_text">
1760
1761<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1762<p>A vector type is a simple derived type that represents a vector of elements.
1763 Vector types are used when multiple primitive data are operated in parallel
1764 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1765 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1766 <a href="#t_firstclass">first class</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767
1768<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1769<pre>
1770 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1771</pre>
1772
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1773<p>The number of elements is a constant integer value; elementtype may be any
1774 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775
1776<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777<table class="layout">
1778 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1779 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1780 <td class="left">Vector of 4 32-bit integer values.</td>
1781 </tr>
1782 <tr class="layout">
1783 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1784 <td class="left">Vector of 8 32-bit floating-point values.</td>
1785 </tr>
1786 <tr class="layout">
1787 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1788 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1789 </tr>
1790</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1792</div>
1793
1794<!-- _______________________________________________________________________ -->
1795<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1796<div class="doc_text">
1797
1798<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1799<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1800 corresponds (for example) to the C notion of a forward declared structure
1801 type. In LLVM, opaque types can eventually be resolved to any type (not just
1802 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1803
1804<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1805<pre>
1806 opaque
1807</pre>
1808
1809<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1810<table class="layout">
1811 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1812 <td class="left"><tt>opaque</tt></td>
1813 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1814 </tr>
1815</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817</div>
1818
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1819<!-- ======================================================================= -->
1820<div class="doc_subsection">
1821 <a name="t_uprefs">Type Up-references</a>
1822</div>
1823
1824<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1825
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1826<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1827<p>An "up reference" allows you to refer to a lexically enclosing type without
1828 requiring it to have a name. For instance, a structure declaration may
1829 contain a pointer to any of the types it is lexically a member of. Example
1830 of up references (with their equivalent as named type declarations)
1831 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1832
1833<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1834 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1835 { \2 }* %y = type { %y }*
1836 \1* %z = type %z*
1837</pre>
1838
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1839<p>An up reference is needed by the asmprinter for printing out cyclic types
1840 when there is no declared name for a type in the cycle. Because the
1841 asmprinter does not want to print out an infinite type string, it needs a
1842 syntax to handle recursive types that have no names (all names are optional
1843 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1844
1845<h5>Syntax:</h5>
1846<pre>
1847 \&lt;level&gt;
1848</pre>
1849
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1850<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]1851
1852<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1853<table class="layout">
1854 <tr class="layout">
1855 <td class="left"><tt>\1*</tt></td>
1856 <td class="left">Self-referential pointer.</td>
1857 </tr>
1858 <tr class="layout">
1859 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1860 <td class="left">Recursive structure where the upref refers to the out-most
1861 structure.</td>
1862 </tr>
1863</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1864
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1865</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1866
1867<!-- *********************************************************************** -->
1868<div class="doc_section"> <a name="constants">Constants</a> </div>
1869<!-- *********************************************************************** -->
1870
1871<div class="doc_text">
1872
1873<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1874 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1875
1876</div>
1877
1878<!-- ======================================================================= -->
1879<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1880
1881<div class="doc_text">
1882
1883<dl>
1884 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1885 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1886 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1887
1888 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1889 <dd>Standard integers (such as '4') are constants of
1890 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1891 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1892
1893 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1894 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1895 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1896 notation (see below). The assembler requires the exact decimal value of a
1897 floating-point constant. For example, the assembler accepts 1.25 but
1898 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1899 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1900
1901 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1902 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1903 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1904</dl>
1905
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1906<p>The one non-intuitive notation for constants is the hexadecimal form of
1907 floating point constants. For example, the form '<tt>double
1908 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1909 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1910 constants are required (and the only time that they are generated by the
1911 disassembler) is when a floating point constant must be emitted but it cannot
1912 be represented as a decimal floating point number in a reasonable number of
1913 digits. For example, NaN's, infinities, and other special values are
1914 represented in their IEEE hexadecimal format so that assembly and disassembly
1915 do not cause any bits to change in the constants.</p>
1916
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1917<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1918 represented using the 16-digit form shown above (which matches the IEEE754
1919 representation for double); float values must, however, be exactly
1920 representable as IEE754 single precision. Hexadecimal format is always used
1921 for long double, and there are three forms of long double. The 80-bit format
1922 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1923 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1924 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1925 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1926 currently supported target uses this format. Long doubles will only work if
1927 they match the long double format on your target. All hexadecimal formats
1928 are big-endian (sign bit at the left).</p>
1929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1930</div>
1931
1932<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1933<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1934<a name="aggregateconstants"></a> <!-- old anchor -->
1935<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1936</div>
1937
1938<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1939
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1940<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1941 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1942
1943<dl>
1944 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1945 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1946 type definitions (a comma separated list of elements, surrounded by braces
1947 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1948 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1949 Structure constants must have <a href="#t_struct">structure type</a>, and
1950 the number and types of elements must match those specified by the
1951 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1952
1953 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1954 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1955 definitions (a comma separated list of elements, surrounded by square
1956 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1957 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1958 the number and types of elements must match those specified by the
1959 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1960
1961 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1962 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1963 definitions (a comma separated list of elements, surrounded by
1964 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
1965 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
1966 have <a href="#t_vector">vector type</a>, and the number and types of
1967 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1968
1969 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1970 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1971 value to zero of <em>any</em> type, including scalar and aggregate types.
1972 This is often used to avoid having to print large zero initializers
1973 (e.g. for large arrays) and is always exactly equivalent to using explicit
1974 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1975
1976 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1977 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1978 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
1979 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
1980 be interpreted as part of the instruction stream, metadata is a place to
1981 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1982</dl>
1983
1984</div>
1985
1986<!-- ======================================================================= -->
1987<div class="doc_subsection">
1988 <a name="globalconstants">Global Variable and Function Addresses</a>
1989</div>
1990
1991<div class="doc_text">
1992
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1993<p>The addresses of <a href="#globalvars">global variables</a>
1994 and <a href="#functionstructure">functions</a> are always implicitly valid
1995 (link-time) constants. These constants are explicitly referenced when
1996 the <a href="#identifiers">identifier for the global</a> is used and always
1997 have <a href="#t_pointer">pointer</a> type. For example, the following is a
1998 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1999
2000<div class="doc_code">
2001<pre>
2002@X = global i32 17
2003@Y = global i32 42
2004@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2005</pre>
2006</div>
2007
2008</div>
2009
2010<!-- ======================================================================= -->
2011<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2012<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2013
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2014<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]2015 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2016 Undefined values may be of any type (other than label or void) and be used
2017 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2018
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2019<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2020 program is well defined no matter what value is used. This gives the
2021 compiler more freedom to optimize. Here are some examples of (potentially
2022 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2023
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2024
2025<div class="doc_code">
2026<pre>
2027 %A = add %X, undef
2028 %B = sub %X, undef
2029 %C = xor %X, undef
2030Safe:
2031 %A = undef
2032 %B = undef
2033 %C = undef
2034</pre>
2035</div>
2036
2037<p>This is safe because all of the output bits are affected by the undef bits.
2038Any output bit can have a zero or one depending on the input bits.</p>
2039
2040<div class="doc_code">
2041<pre>
2042 %A = or %X, undef
2043 %B = and %X, undef
2044Safe:
2045 %A = -1
2046 %B = 0
2047Unsafe:
2048 %A = undef
2049 %B = undef
2050</pre>
2051</div>
2052
2053<p>These logical operations have bits that are not always affected by the input.
2054For example, if "%X" has a zero bit, then the output of the 'and' operation will
2055always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2056such, it is unsafe to optimize or assume that the result of the and is undef.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2057However, it is safe to assume that all bits of the undef could be 0, and
2058optimize the and to 0. Likewise, it is safe to assume that all the bits of
2059the undef operand to the or could be set, allowing the or to be folded to
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2060-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2061
2062<div class="doc_code">
2063<pre>
2064 %A = select undef, %X, %Y
2065 %B = select undef, 42, %Y
2066 %C = select %X, %Y, undef
2067Safe:
2068 %A = %X (or %Y)
2069 %B = 42 (or %Y)
2070 %C = %Y
2071Unsafe:
2072 %A = undef
2073 %B = undef
2074 %C = undef
2075</pre>
2076</div>
2077
2078<p>This set of examples show that undefined select (and conditional branch)
2079conditions can go "either way" but they have to come from one of the two
2080operands. In the %A example, if %X and %Y were both known to have a clear low
2081bit, then %A would have to have a cleared low bit. However, in the %C example,
2082the optimizer is allowed to assume that the undef operand could be the same as
2083%Y, allowing the whole select to be eliminated.</p>
2084
2085
2086<div class="doc_code">
2087<pre>
2088 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2089
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2090 %B = undef
2091 %C = xor %B, %B
2092
2093 %D = undef
2094 %E = icmp lt %D, 4
2095 %F = icmp gte %D, 4
2096
2097Safe:
2098 %A = undef
2099 %B = undef
2100 %C = undef
2101 %D = undef
2102 %E = undef
2103 %F = undef
2104</pre>
2105</div>
2106
2107<p>This example points out that two undef operands are not necessarily the same.
2108This can be surprising to people (and also matches C semantics) where they
2109assume that "X^X" is always zero, even if X is undef. This isn't true for a
2110number of reasons, but the short answer is that an undef "variable" can
2111arbitrarily change its value over its "live range". This is true because the
2112"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2113logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2114so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2115to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2116would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2117
2118<div class="doc_code">
2119<pre>
2120 %A = fdiv undef, %X
2121 %B = fdiv %X, undef
2122Safe:
2123 %A = undef
2124b: unreachable
2125</pre>
2126</div>
2127
2128<p>These examples show the crucial difference between an <em>undefined
2129value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2130allowed to have an arbitrary bit-pattern. This means that the %A operation
2131can be constant folded to undef because the undef could be an SNaN, and fdiv is
2132not (currently) defined on SNaN's. However, in the second example, we can make
2133a more aggressive assumption: because the undef is allowed to be an arbitrary
2134value, 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]2135has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2136does not execute at all. This allows us to delete the divide and all code after
2137it: since the undefined operation "can't happen", the optimizer can assume that
2138it occurs in dead code.
2139</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2140
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2141<div class="doc_code">
2142<pre>
2143a: store undef -> %X
2144b: store %X -> undef
2145Safe:
2146a: &lt;deleted&gt;
2147b: unreachable
2148</pre>
2149</div>
2150
2151<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2152can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2153overwritten with bits that happen to match what was already there. However, a
2154store "to" an undefined location could clobber arbitrary memory, therefore, it
2155has undefined behavior.</p>
2156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2157</div>
2158
2159<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2160<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2161 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2162<div class="doc_text">
2163
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2164<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2165
2166<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2167 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2168 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2169
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2170<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2171 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2172 against null. Pointer equality tests between labels addresses is undefined
2173 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2174 equal to the null pointer. This may also be passed around as an opaque
2175 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2176 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2177 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2178
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2179<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2180 using the value as the operand to an inline assembly, but that is target
2181 specific.
2182 </p>
2183
2184</div>
2185
2186
2187<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2188<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2189</div>
2190
2191<div class="doc_text">
2192
2193<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2194 to be used as constants. Constant expressions may be of
2195 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2196 operation that does not have side effects (e.g. load and call are not
2197 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2198
2199<dl>
2200 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2201 <dd>Truncate a constant to another type. The bit size of CST must be larger
2202 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2203
2204 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2205 <dd>Zero extend a constant to another type. The bit size of CST must be
2206 smaller or equal to the bit size of TYPE. Both types must be
2207 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208
2209 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2210 <dd>Sign extend a constant to another type. The bit size of CST must be
2211 smaller or equal to the bit size of TYPE. Both types must be
2212 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2213
2214 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2215 <dd>Truncate a floating point constant to another floating point type. The
2216 size of CST must be larger than the size of TYPE. Both types must be
2217 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2218
2219 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2220 <dd>Floating point extend a constant to another type. The size of CST must be
2221 smaller or equal to the size of TYPE. Both types must be floating
2222 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2223
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2224 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2225 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2226 constant. TYPE must be a scalar or vector integer type. CST must be of
2227 scalar or vector floating point type. Both CST and TYPE must be scalars,
2228 or vectors of the same number of elements. If the value won't fit in the
2229 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2230
2231 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2232 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2233 constant. TYPE must be a scalar or vector integer type. CST must be of
2234 scalar or vector floating point type. Both CST and TYPE must be scalars,
2235 or vectors of the same number of elements. If the value won't fit in the
2236 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2237
2238 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2239 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2240 constant. TYPE must be a scalar or vector floating point type. CST must be
2241 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2242 vectors of the same number of elements. If the value won't fit in the
2243 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244
2245 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2246 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2247 constant. TYPE must be a scalar or vector floating point type. CST must be
2248 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2249 vectors of the same number of elements. If the value won't fit in the
2250 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2251
2252 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2253 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2254 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2255 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2256 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2257
2258 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2259 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2260 type. CST must be of integer type. The CST value is zero extended,
2261 truncated, or unchanged to make it fit in a pointer size. This one is
2262 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263
2264 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2265 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2266 are the same as those for the <a href="#i_bitcast">bitcast
2267 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2268
2269 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2270 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2271 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2272 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2273 instruction, the index list may have zero or more indexes, which are
2274 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2275
2276 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2277 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2278
2279 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2280 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2281
2282 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2283 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2284
2285 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2286 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2287 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2288
2289 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2290 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2291 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2292
2293 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2294 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2295 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2296
2297 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2298 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2299 be any of the <a href="#binaryops">binary</a>
2300 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2301 on operands are the same as those for the corresponding instruction
2302 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2303</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2305</div>
2306
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2307<!-- ======================================================================= -->
2308<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2309</div>
2310
2311<div class="doc_text">
2312
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2313<p>Embedded metadata provides a way to attach arbitrary data to the instruction
2314 stream without affecting the behaviour of the program. There are two
2315 metadata primitives, strings and nodes. All metadata has the
2316 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2317 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2318
2319<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2320 any character by escaping non-printable characters with "\xx" where "xx" is
2321 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2322
2323<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2324 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2325 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2326 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2327
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2328<p>A metadata node will attempt to track changes to the values it holds. In the
2329 event that a value is deleted, it will be replaced with a typeless
2330 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2331
Devang Patelc5bb7252010-01-05 20:41:31 +0000[diff] [blame]2332<p>A named metadata is a collection of metadata nodes. For example: "<tt>!foo =
2333 metadata !{!4, !3}</tt>".
2334
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2335<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2336 the program that isn't available in the instructions, or that isn't easily
2337 computable. Similarly, the code generator may expect a certain metadata
2338 format to be used to express debugging information.</p>
2339
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2340</div>
2341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2342<!-- *********************************************************************** -->
2343<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2344<!-- *********************************************************************** -->
2345
2346<!-- ======================================================================= -->
2347<div class="doc_subsection">
2348<a name="inlineasm">Inline Assembler Expressions</a>
2349</div>
2350
2351<div class="doc_text">
2352
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2353<p>LLVM supports inline assembler expressions (as opposed
2354 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2355 a special value. This value represents the inline assembler as a string
2356 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2357 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2358 expression has side effects, and a flag indicating whether the function
2359 containing the asm needs to align its stack conservatively. An example
2360 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2361
2362<div class="doc_code">
2363<pre>
2364i32 (i32) asm "bswap $0", "=r,r"
2365</pre>
2366</div>
2367
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2368<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2369 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2370 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2371
2372<div class="doc_code">
2373<pre>
2374%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2375</pre>
2376</div>
2377
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2378<p>Inline asms with side effects not visible in the constraint list must be
2379 marked as having side effects. This is done through the use of the
2380 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2381
2382<div class="doc_code">
2383<pre>
2384call void asm sideeffect "eieio", ""()
2385</pre>
2386</div>
2387
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2388<p>In some cases inline asms will contain code that will not work unless the
2389 stack is aligned in some way, such as calls or SSE instructions on x86,
2390 yet will not contain code that does that alignment within the asm.
2391 The compiler should make conservative assumptions about what the asm might
2392 contain and should generate its usual stack alignment code in the prologue
2393 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2394
2395<div class="doc_code">
2396<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2397call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2398</pre>
2399</div>
2400
2401<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2402 first.</p>
2403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2405 documented here. Constraints on what can be done (e.g. duplication, moving,
2406 etc need to be documented). This is probably best done by reference to
2407 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2408
2409</div>
2410
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2411
2412<!-- *********************************************************************** -->
2413<div class="doc_section">
2414 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2415</div>
2416<!-- *********************************************************************** -->
2417
2418<p>LLVM has a number of "magic" global variables that contain data that affect
2419code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2420of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2421section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2422by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2423
2424<!-- ======================================================================= -->
2425<div class="doc_subsection">
2426<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2427</div>
2428
2429<div class="doc_text">
2430
2431<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2432href="#linkage_appending">appending linkage</a>. This array contains a list of
2433pointers to global variables and functions which may optionally have a pointer
2434cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2435
2436<pre>
2437 @X = global i8 4
2438 @Y = global i32 123
2439
2440 @llvm.used = appending global [2 x i8*] [
2441 i8* @X,
2442 i8* bitcast (i32* @Y to i8*)
2443 ], section "llvm.metadata"
2444</pre>
2445
2446<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2447compiler, assembler, and linker are required to treat the symbol as if there is
2448a reference to the global that it cannot see. For example, if a variable has
2449internal linkage and no references other than that from the <tt>@llvm.used</tt>
2450list, it cannot be deleted. This is commonly used to represent references from
2451inline asms and other things the compiler cannot "see", and corresponds to
2452"attribute((used))" in GNU C.</p>
2453
2454<p>On some targets, the code generator must emit a directive to the assembler or
2455object file to prevent the assembler and linker from molesting the symbol.</p>
2456
2457</div>
2458
2459<!-- ======================================================================= -->
2460<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2461<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2462</div>
2463
2464<div class="doc_text">
2465
2466<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2467<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2468touching the symbol. On targets that support it, this allows an intelligent
2469linker to optimize references to the symbol without being impeded as it would be
2470by <tt>@llvm.used</tt>.</p>
2471
2472<p>This is a rare construct that should only be used in rare circumstances, and
2473should not be exposed to source languages.</p>
2474
2475</div>
2476
2477<!-- ======================================================================= -->
2478<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2479<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2480</div>
2481
2482<div class="doc_text">
2483
2484<p>TODO: Describe this.</p>
2485
2486</div>
2487
2488<!-- ======================================================================= -->
2489<div class="doc_subsection">
2490<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2491</div>
2492
2493<div class="doc_text">
2494
2495<p>TODO: Describe this.</p>
2496
2497</div>
2498
2499
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2500<!-- *********************************************************************** -->
2501<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2502<!-- *********************************************************************** -->
2503
2504<div class="doc_text">
2505
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2506<p>The LLVM instruction set consists of several different classifications of
2507 instructions: <a href="#terminators">terminator
2508 instructions</a>, <a href="#binaryops">binary instructions</a>,
2509 <a href="#bitwiseops">bitwise binary instructions</a>,
2510 <a href="#memoryops">memory instructions</a>, and
2511 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512
2513</div>
2514
2515<!-- ======================================================================= -->
2516<div class="doc_subsection"> <a name="terminators">Terminator
2517Instructions</a> </div>
2518
2519<div class="doc_text">
2520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2521<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2522 in a program ends with a "Terminator" instruction, which indicates which
2523 block should be executed after the current block is finished. These
2524 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2525 control flow, not values (the one exception being the
2526 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2527
2528<p>There are six different terminator instructions: the
2529 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2530 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2531 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2532 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2533 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2534 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2535 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2536
2537</div>
2538
2539<!-- _______________________________________________________________________ -->
2540<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2541Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2544
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2545<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2546<pre>
2547 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]2548 ret void <i>; Return from void function</i>
2549</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2550
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2551<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2552<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2553 a value) from a function back to the caller.</p>
2554
2555<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2556 value and then causes control flow, and one that just causes control flow to
2557 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2558
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2560<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2561 return value. The type of the return value must be a
2562 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2563
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2564<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2565 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2566 value or a return value with a type that does not match its type, or if it
2567 has a void return type and contains a '<tt>ret</tt>' instruction with a
2568 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2569
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2570<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2571<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2572 the calling function's context. If the caller is a
2573 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2574 instruction after the call. If the caller was an
2575 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2576 the beginning of the "normal" destination block. If the instruction returns
2577 a value, that value shall set the call or invoke instruction's return
2578 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2581<pre>
2582 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2584 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]2585</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2587</div>
2588<!-- _______________________________________________________________________ -->
2589<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2592
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2593<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2594<pre>
2595 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]2596</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2599<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2600 different basic block in the current function. There are two forms of this
2601 instruction, corresponding to a conditional branch and an unconditional
2602 branch.</p>
2603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2605<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2606 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2607 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2608 target.</p>
2609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2610<h5>Semantics:</h5>
2611<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2612 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2613 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2614 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2617<pre>
2618Test:
2619 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2620 br i1 %cond, label %IfEqual, label %IfUnequal
2621IfEqual:
2622 <a href="#i_ret">ret</a> i32 1
2623IfUnequal:
2624 <a href="#i_ret">ret</a> i32 0
2625</pre>
2626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<!-- _______________________________________________________________________ -->
2630<div class="doc_subsubsection">
2631 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2632</div>
2633
2634<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2635
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2636<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2637<pre>
2638 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2639</pre>
2640
2641<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2642<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]2643 several different places. It is a generalization of the '<tt>br</tt>'
2644 instruction, allowing a branch to occur to one of many possible
2645 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2646
2647<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2648<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2649 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2650 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2651 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2652
2653<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2655 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2656 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2657 transferred to the corresponding destination; otherwise, control flow is
2658 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659
2660<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2661<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2662 <tt>switch</tt> instruction, this instruction may be code generated in
2663 different ways. For example, it could be generated as a series of chained
2664 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2665
2666<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667<pre>
2668 <i>; Emulate a conditional br instruction</i>
2669 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2670 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671
2672 <i>; Emulate an unconditional br instruction</i>
2673 switch i32 0, label %dest [ ]
2674
2675 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2676 switch i32 %val, label %otherwise [ i32 0, label %onzero
2677 i32 1, label %onone
2678 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2680
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2681</div>
2682
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2683
2684<!-- _______________________________________________________________________ -->
2685<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2686 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2687</div>
2688
2689<div class="doc_text">
2690
2691<h5>Syntax:</h5>
2692<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2693 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]2694</pre>
2695
2696<h5>Overview:</h5>
2697
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2698<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2699 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2700 "<tt>address</tt>". Address must be derived from a <a
2701 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2702
2703<h5>Arguments:</h5>
2704
2705<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2706 rest of the arguments indicate the full set of possible destinations that the
2707 address may point to. Blocks are allowed to occur multiple times in the
2708 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2709
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2710<p>This destination list is required so that dataflow analysis has an accurate
2711 understanding of the CFG.</p>
2712
2713<h5>Semantics:</h5>
2714
2715<p>Control transfers to the block specified in the address argument. All
2716 possible destination blocks must be listed in the label list, otherwise this
2717 instruction has undefined behavior. This implies that jumps to labels
2718 defined in other functions have undefined behavior as well.</p>
2719
2720<h5>Implementation:</h5>
2721
2722<p>This is typically implemented with a jump through a register.</p>
2723
2724<h5>Example:</h5>
2725<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2726 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2727</pre>
2728
2729</div>
2730
2731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<!-- _______________________________________________________________________ -->
2733<div class="doc_subsubsection">
2734 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2735</div>
2736
2737<div class="doc_text">
2738
2739<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2740<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2741 &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]2742 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2743</pre>
2744
2745<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2746<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2747 function, with the possibility of control flow transfer to either the
2748 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2749 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2750 control flow will return to the "normal" label. If the callee (or any
2751 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2752 instruction, control is interrupted and continued at the dynamically nearest
2753 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2754
2755<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756<p>This instruction requires several arguments:</p>
2757
2758<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2759 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2760 convention</a> the call should use. If none is specified, the call
2761 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2762
2763 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2764 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2765 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2767 <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]2768 function value being invoked. In most cases, this is a direct function
2769 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2770 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2771
2772 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2773 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2774
2775 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2776 signature argument types. If the function signature indicates the
2777 function accepts a variable number of arguments, the extra arguments can
2778 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779
2780 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2781 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782
2783 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2784 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2785
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2786 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2787 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2788 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2789</ol>
2790
2791<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2792<p>This instruction is designed to operate as a standard
2793 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2794 primary difference is that it establishes an association with a label, which
2795 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2796
2797<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2798 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2799 exception. Additionally, this is important for implementation of
2800 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2801
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2802<p>For the purposes of the SSA form, the definition of the value returned by the
2803 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2804 block to the "normal" label. If the callee unwinds then no return value is
2805 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807<h5>Example:</h5>
2808<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2809 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2810 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2811 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812 unwind label %TestCleanup <i>; {i32}:retval set</i>
2813</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2814
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2815</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2816
2817<!-- _______________________________________________________________________ -->
2818
2819<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2820Instruction</a> </div>
2821
2822<div class="doc_text">
2823
2824<h5>Syntax:</h5>
2825<pre>
2826 unwind
2827</pre>
2828
2829<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2830<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2831 at the first callee in the dynamic call stack which used
2832 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2833 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2834
2835<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2836<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2837 immediately halt. The dynamic call stack is then searched for the
2838 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2839 Once found, execution continues at the "exceptional" destination block
2840 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2841 instruction in the dynamic call chain, undefined behavior results.</p>
2842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2843</div>
2844
2845<!-- _______________________________________________________________________ -->
2846
2847<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2848Instruction</a> </div>
2849
2850<div class="doc_text">
2851
2852<h5>Syntax:</h5>
2853<pre>
2854 unreachable
2855</pre>
2856
2857<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2858<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2859 instruction is used to inform the optimizer that a particular portion of the
2860 code is not reachable. This can be used to indicate that the code after a
2861 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862
2863<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2864<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2865
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866</div>
2867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868<!-- ======================================================================= -->
2869<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2871<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2872
2873<p>Binary operators are used to do most of the computation in a program. They
2874 require two operands of the same type, execute an operation on them, and
2875 produce a single value. The operands might represent multiple data, as is
2876 the case with the <a href="#t_vector">vector</a> data type. The result value
2877 has the same type as its operands.</p>
2878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2879<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2881</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2883<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2884<div class="doc_subsubsection">
2885 <a name="i_add">'<tt>add</tt>' Instruction</a>
2886</div>
2887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2888<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2889
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2890<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2891<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2892 &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]2893 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2894 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2895 &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]2896</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898<h5>Overview:</h5>
2899<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2900
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2901<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2902<p>The two arguments to the '<tt>add</tt>' instruction must
2903 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2904 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2906<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2907<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2908
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2909<p>If the sum has unsigned overflow, the result returned is the mathematical
2910 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]2911
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2912<p>Because LLVM integers use a two's complement representation, this instruction
2913 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2914
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2915<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2916 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2917 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2918 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2921<pre>
2922 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2923</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2927<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2928<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2929 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2930</div>
2931
2932<div class="doc_text">
2933
2934<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2935<pre>
2936 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2937</pre>
2938
2939<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2940<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2941
2942<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2943<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2944 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2945 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2946
2947<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2948<p>The value produced is the floating point sum of the two operands.</p>
2949
2950<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2951<pre>
2952 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2953</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2954
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2955</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2956
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2957<!-- _______________________________________________________________________ -->
2958<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2959 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2960</div>
2961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2962<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2964<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2965<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2966 &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]2967 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2968 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2969 &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]2970</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2972<h5>Overview:</h5>
2973<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2974 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2975
2976<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2977 '<tt>neg</tt>' instruction present in most other intermediate
2978 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2979
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2981<p>The two arguments to the '<tt>sub</tt>' instruction must
2982 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2983 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2984
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2985<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2986<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2987
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2988<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2989 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2990 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2991
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2992<p>Because LLVM integers use a two's complement representation, this instruction
2993 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2994
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2995<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2996 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2997 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2998 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3000<h5>Example:</h5>
3001<pre>
3002 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3003 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3004</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3006</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3007
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3008<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3009<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3010 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3011</div>
3012
3013<div class="doc_text">
3014
3015<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3016<pre>
3017 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3018</pre>
3019
3020<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3021<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3022 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3023
3024<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3025 '<tt>fneg</tt>' instruction present in most other intermediate
3026 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3027
3028<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3029<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3030 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3031 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3032
3033<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3034<p>The value produced is the floating point difference of the two operands.</p>
3035
3036<h5>Example:</h5>
3037<pre>
3038 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3039 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3040</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3041
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3042</div>
3043
3044<!-- _______________________________________________________________________ -->
3045<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3046 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3047</div>
3048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3051<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3052<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3053 &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]3054 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3055 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3056 &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]3057</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3058
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3059<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3060<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3061
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3062<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3063<p>The two arguments to the '<tt>mul</tt>' instruction must
3064 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3065 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3066
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3067<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3068<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3069
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3070<p>If the result of the multiplication has unsigned overflow, the result
3071 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3072 width of the result.</p>
3073
3074<p>Because LLVM integers use a two's complement representation, and the result
3075 is the same width as the operands, this instruction returns the correct
3076 result for both signed and unsigned integers. If a full product
3077 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3078 be sign-extended or zero-extended as appropriate to the width of the full
3079 product.</p>
3080
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3081<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3082 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3083 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3084 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3086<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3087<pre>
3088 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3089</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3090
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3091</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3092
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3093<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3094<div class="doc_subsubsection">
3095 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3096</div>
3097
3098<div class="doc_text">
3099
3100<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3101<pre>
3102 &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]3103</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3104
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3105<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3106<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3107
3108<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3109<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3110 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3111 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3112
3113<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3114<p>The value produced is the floating point product of the two operands.</p>
3115
3116<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3117<pre>
3118 &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]3119</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3120
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3121</div>
3122
3123<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3124<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3125</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3129<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3130<pre>
3131 &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]3132</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3134<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3135<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3138<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3139 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3140 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3142<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3143<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3144
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3145<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3146 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3147
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3148<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3149
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3150<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3151<pre>
3152 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3154
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3155</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3157<!-- _______________________________________________________________________ -->
3158<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3159</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3160
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3163<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3164<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3165 &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]3166 &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]3167</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3169<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3170<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3173<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3174 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3175 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3177<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3178<p>The value produced is the signed integer quotient of the two operands rounded
3179 towards zero.</p>
3180
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3181<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3182 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3183
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3184<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3185 undefined behavior; this is a rare case, but can occur, for example, by doing
3186 a 32-bit division of -2147483648 by -1.</p>
3187
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3188<p>If the <tt>exact</tt> keyword is present, the result value of the
3189 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3190 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3191
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3192<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3193<pre>
3194 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3195</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3197</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3199<!-- _______________________________________________________________________ -->
3200<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3201Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3203<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3204
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3205<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3206<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3207 &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]3208</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3209
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3210<h5>Overview:</h5>
3211<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3213<h5>Arguments:</h5>
3214<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3215 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3216 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3218<h5>Semantics:</h5>
3219<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3221<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3222<pre>
3223 &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]3224</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3226</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3228<!-- _______________________________________________________________________ -->
3229<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3230</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3232<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3234<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235<pre>
3236 &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]3237</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3239<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3240<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3241 division of its two arguments.</p>
3242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3244<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3245 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3246 values. Both arguments must have identical types.</p>
3247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3248<h5>Semantics:</h5>
3249<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3250 This instruction always performs an unsigned division to get the
3251 remainder.</p>
3252
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3253<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3254 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3255
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3256<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3258<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3259<pre>
3260 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3261</pre>
3262
3263</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3264
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3265<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3266<div class="doc_subsubsection">
3267 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3268</div>
3269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3270<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3272<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3273<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3274 &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]3275</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3276
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3277<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3278<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3279 division of its two operands. This instruction can also take
3280 <a href="#t_vector">vector</a> versions of the values in which case the
3281 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3282
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3283<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3284<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3285 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3286 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3288<h5>Semantics:</h5>
3289<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3291 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3292 a value. For more information about the difference,
3293 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3294 Math Forum</a>. For a table of how this is implemented in various languages,
3295 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3296 Wikipedia: modulo operation</a>.</p>
3297
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3298<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3299 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3300
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3301<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3302 Overflow also leads to undefined behavior; this is a rare case, but can
3303 occur, for example, by taking the remainder of a 32-bit division of
3304 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3305 lets srem be implemented using instructions that return both the result of
3306 the division and the remainder.)</p>
3307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3308<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3309<pre>
3310 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3311</pre>
3312
3313</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3315<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3316<div class="doc_subsubsection">
3317 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3319<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3321<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322<pre>
3323 &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]3324</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3325
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3326<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3327<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3328 its two operands.</p>
3329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3330<h5>Arguments:</h5>
3331<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3332 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3333 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3334
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3335<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3336<p>This instruction returns the <i>remainder</i> of a division. The remainder
3337 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3340<pre>
3341 &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]3342</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344</div>
3345
3346<!-- ======================================================================= -->
3347<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3348Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3349
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3351
3352<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3353 program. They are generally very efficient instructions and can commonly be
3354 strength reduced from other instructions. They require two operands of the
3355 same type, execute an operation on them, and produce a single value. The
3356 resulting value is the same type as its operands.</p>
3357
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3358</div>
3359
3360<!-- _______________________________________________________________________ -->
3361<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3362Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3364<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3367<pre>
3368 &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]3369</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3371<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3372<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3373 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3375<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3376<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3377 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3378 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3380<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3381<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3382 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3383 is (statically or dynamically) negative or equal to or larger than the number
3384 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3385 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3386 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3387
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3388<h5>Example:</h5>
3389<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3390 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3391 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3392 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3393 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3394 &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]3395</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3397</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3399<!-- _______________________________________________________________________ -->
3400<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3401Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3403<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3404
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3405<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3406<pre>
3407 &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]3408</pre>
3409
3410<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3411<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3412 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3413
3414<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3415<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3416 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3417 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3418
3419<h5>Semantics:</h5>
3420<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3421 significant bits of the result will be filled with zero bits after the shift.
3422 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3423 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3424 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3425 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426
3427<h5>Example:</h5>
3428<pre>
3429 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3430 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3431 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3432 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3433 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3434 &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]3435</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437</div>
3438
3439<!-- _______________________________________________________________________ -->
3440<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3441Instruction</a> </div>
3442<div class="doc_text">
3443
3444<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3445<pre>
3446 &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]3447</pre>
3448
3449<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3450<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3451 operand shifted to the right a specified number of bits with sign
3452 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3453
3454<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3455<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3456 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3457 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3458
3459<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3460<p>This instruction always performs an arithmetic shift right operation, The
3461 most significant bits of the result will be filled with the sign bit
3462 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3463 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3464 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3465 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3466
3467<h5>Example:</h5>
3468<pre>
3469 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3470 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3471 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3472 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3473 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3474 &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]3475</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3477</div>
3478
3479<!-- _______________________________________________________________________ -->
3480<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3481Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3482
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3483<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3484
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3486<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3487 &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]3488</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3491<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3492 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3494<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3495<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3496 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3497 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3499<h5>Semantics:</h5>
3500<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3502<table border="1" cellspacing="0" cellpadding="4">
3503 <tbody>
3504 <tr>
3505 <td>In0</td>
3506 <td>In1</td>
3507 <td>Out</td>
3508 </tr>
3509 <tr>
3510 <td>0</td>
3511 <td>0</td>
3512 <td>0</td>
3513 </tr>
3514 <tr>
3515 <td>0</td>
3516 <td>1</td>
3517 <td>0</td>
3518 </tr>
3519 <tr>
3520 <td>1</td>
3521 <td>0</td>
3522 <td>0</td>
3523 </tr>
3524 <tr>
3525 <td>1</td>
3526 <td>1</td>
3527 <td>1</td>
3528 </tr>
3529 </tbody>
3530</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3532<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3533<pre>
3534 &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]3535 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3536 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3537</pre>
3538</div>
3539<!-- _______________________________________________________________________ -->
3540<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3541
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3542<div class="doc_text">
3543
3544<h5>Syntax:</h5>
3545<pre>
3546 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3547</pre>
3548
3549<h5>Overview:</h5>
3550<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3551 two operands.</p>
3552
3553<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3554<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3555 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3556 values. Both arguments must have identical types.</p>
3557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3558<h5>Semantics:</h5>
3559<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561<table border="1" cellspacing="0" cellpadding="4">
3562 <tbody>
3563 <tr>
3564 <td>In0</td>
3565 <td>In1</td>
3566 <td>Out</td>
3567 </tr>
3568 <tr>
3569 <td>0</td>
3570 <td>0</td>
3571 <td>0</td>
3572 </tr>
3573 <tr>
3574 <td>0</td>
3575 <td>1</td>
3576 <td>1</td>
3577 </tr>
3578 <tr>
3579 <td>1</td>
3580 <td>0</td>
3581 <td>1</td>
3582 </tr>
3583 <tr>
3584 <td>1</td>
3585 <td>1</td>
3586 <td>1</td>
3587 </tr>
3588 </tbody>
3589</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3591<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3592<pre>
3593 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3594 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3595 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3596</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3598</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3599
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3600<!-- _______________________________________________________________________ -->
3601<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3602Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3604<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3606<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3607<pre>
3608 &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]3609</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3610
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3611<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3612<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3613 its two operands. The <tt>xor</tt> is used to implement the "one's
3614 complement" operation, which is the "~" operator in C.</p>
3615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3616<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3617<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3618 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3619 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3621<h5>Semantics:</h5>
3622<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3624<table border="1" cellspacing="0" cellpadding="4">
3625 <tbody>
3626 <tr>
3627 <td>In0</td>
3628 <td>In1</td>
3629 <td>Out</td>
3630 </tr>
3631 <tr>
3632 <td>0</td>
3633 <td>0</td>
3634 <td>0</td>
3635 </tr>
3636 <tr>
3637 <td>0</td>
3638 <td>1</td>
3639 <td>1</td>
3640 </tr>
3641 <tr>
3642 <td>1</td>
3643 <td>0</td>
3644 <td>1</td>
3645 </tr>
3646 <tr>
3647 <td>1</td>
3648 <td>1</td>
3649 <td>0</td>
3650 </tr>
3651 </tbody>
3652</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3654<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3655<pre>
3656 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3657 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3658 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3659 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3660</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3662</div>
3663
3664<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3665<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3666 <a name="vectorops">Vector Operations</a>
3667</div>
3668
3669<div class="doc_text">
3670
3671<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3672 target-independent manner. These instructions cover the element-access and
3673 vector-specific operations needed to process vectors effectively. While LLVM
3674 does directly support these vector operations, many sophisticated algorithms
3675 will want to use target-specific intrinsics to take full advantage of a
3676 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3677
3678</div>
3679
3680<!-- _______________________________________________________________________ -->
3681<div class="doc_subsubsection">
3682 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3683</div>
3684
3685<div class="doc_text">
3686
3687<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3688<pre>
3689 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3690</pre>
3691
3692<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3693<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3694 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3695
3696
3697<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3698<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3699 of <a href="#t_vector">vector</a> type. The second operand is an index
3700 indicating the position from which to extract the element. The index may be
3701 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702
3703<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3704<p>The result is a scalar of the same type as the element type of
3705 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3706 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3707 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3708
3709<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3711 &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]3712</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3713
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3714</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3715
3716<!-- _______________________________________________________________________ -->
3717<div class="doc_subsubsection">
3718 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3719</div>
3720
3721<div class="doc_text">
3722
3723<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3724<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3725 &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]3726</pre>
3727
3728<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3729<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3730 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3731
3732<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3733<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3734 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3735 whose type must equal the element type of the first operand. The third
3736 operand is an index indicating the position at which to insert the value.
3737 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3738
3739<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3740<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3741 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3742 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3743 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3744
3745<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3747 &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]3748</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3750</div>
3751
3752<!-- _______________________________________________________________________ -->
3753<div class="doc_subsubsection">
3754 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3755</div>
3756
3757<div class="doc_text">
3758
3759<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3760<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3761 &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]3762</pre>
3763
3764<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3765<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3766 from two input vectors, returning a vector with the same element type as the
3767 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3768
3769<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3770<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3771 with types that match each other. The third argument is a shuffle mask whose
3772 element type is always 'i32'. The result of the instruction is a vector
3773 whose length is the same as the shuffle mask and whose element type is the
3774 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The shuffle mask operand is required to be a constant vector with either
3777 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3778
3779<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3780<p>The elements of the two input vectors are numbered from left to right across
3781 both of the vectors. The shuffle mask operand specifies, for each element of
3782 the result vector, which element of the two input vectors the result element
3783 gets. The element selector may be undef (meaning "don't care") and the
3784 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3785
3786<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3787<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3788 &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]3789 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3790 &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]3791 &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.
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3792 &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]3793 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3794 &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]3795 &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]3796</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3797
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3798</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3799
3800<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3801<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3802 <a name="aggregateops">Aggregate Operations</a>
3803</div>
3804
3805<div class="doc_text">
3806
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3807<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3808
3809</div>
3810
3811<!-- _______________________________________________________________________ -->
3812<div class="doc_subsubsection">
3813 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3814</div>
3815
3816<div class="doc_text">
3817
3818<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3819<pre>
3820 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3821</pre>
3822
3823<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3824<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3825 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3826
3827<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3828<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3829 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3830 operands are constant indices to specify which value to extract in a similar
3831 manner as indices in a
3832 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3833
3834<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3835<p>The result is the value at the position in the aggregate specified by the
3836 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3837
3838<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3839<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3840 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3841</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3842
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3843</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3844
3845<!-- _______________________________________________________________________ -->
3846<div class="doc_subsubsection">
3847 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3848</div>
3849
3850<div class="doc_text">
3851
3852<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3853<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3854 &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]3855</pre>
3856
3857<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3858<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3859 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3860
3861
3862<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3863<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3864 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3865 second operand is a first-class value to insert. The following operands are
3866 constant indices indicating the position at which to insert the value in a
3867 similar manner as indices in a
3868 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3869 value to insert must have the same type as the value identified by the
3870 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3871
3872<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3873<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3874 that of <tt>val</tt> except that the value at the position specified by the
3875 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3876
3877<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3878<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3879 &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]3880</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3881
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3882</div>
3883
3884
3885<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3886<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3887 <a name="memoryops">Memory Access and Addressing Operations</a>
3888</div>
3889
3890<div class="doc_text">
3891
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3892<p>A key design point of an SSA-based representation is how it represents
3893 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3894 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3895 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3896
3897</div>
3898
3899<!-- _______________________________________________________________________ -->
3900<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3901 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3902</div>
3903
3904<div class="doc_text">
3905
3906<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3907<pre>
3908 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3909</pre>
3910
3911<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3913 currently executing function, to be automatically released when this function
3914 returns to its caller. The object is always allocated in the generic address
3915 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3916
3917<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3918<p>The '<tt>alloca</tt>' instruction
3919 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3920 runtime stack, returning a pointer of the appropriate type to the program.
3921 If "NumElements" is specified, it is the number of elements allocated,
3922 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3923 specified, the value result of the allocation is guaranteed to be aligned to
3924 at least that boundary. If not specified, or if zero, the target can choose
3925 to align the allocation on any convenient boundary compatible with the
3926 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3927
3928<p>'<tt>type</tt>' may be any sized type.</p>
3929
3930<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3931<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3932 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3933 memory is automatically released when the function returns. The
3934 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3935 variables that must have an address available. When the function returns
3936 (either with the <tt><a href="#i_ret">ret</a></tt>
3937 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3938 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3939
3940<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3941<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3942 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3943 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3944 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3945 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3946</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3947
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3948</div>
3949
3950<!-- _______________________________________________________________________ -->
3951<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3952Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3954<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3956<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3957<pre>
3958 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3959 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3960</pre>
3961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3962<h5>Overview:</h5>
3963<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3966<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3967 from which to load. The pointer must point to
3968 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3969 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3970 number or order of execution of this <tt>load</tt> with other
3971 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3972 instructions. </p>
3973
3974<p>The optional constant "align" argument specifies the alignment of the
3975 operation (that is, the alignment of the memory address). A value of 0 or an
3976 omitted "align" argument means that the operation has the preferential
3977 alignment for the target. It is the responsibility of the code emitter to
3978 ensure that the alignment information is correct. Overestimating the
3979 alignment results in an undefined behavior. Underestimating the alignment may
3980 produce less efficient code. An alignment of 1 is always safe.</p>
3981
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3982<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3983<p>The location of memory pointed to is loaded. If the value being loaded is of
3984 scalar type then the number of bytes read does not exceed the minimum number
3985 of bytes needed to hold all bits of the type. For example, loading an
3986 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3987 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3988 is undefined if the value was not originally written using a store of the
3989 same type.</p>
3990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3991<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3992<pre>
3993 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3994 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3995 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3996</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3998</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000<!-- _______________________________________________________________________ -->
4001<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4002Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4003
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4004<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4006<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4007<pre>
4008 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]4009 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4010</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4012<h5>Overview:</h5>
4013<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4014
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4015<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4016<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4017 and an address at which to store it. The type of the
4018 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4019 the <a href="#t_firstclass">first class</a> type of the
4020 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4021 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4022 or order of execution of this <tt>store</tt> with other
4023 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4024 instructions.</p>
4025
4026<p>The optional constant "align" argument specifies the alignment of the
4027 operation (that is, the alignment of the memory address). A value of 0 or an
4028 omitted "align" argument means that the operation has the preferential
4029 alignment for the target. It is the responsibility of the code emitter to
4030 ensure that the alignment information is correct. Overestimating the
4031 alignment results in an undefined behavior. Underestimating the alignment may
4032 produce less efficient code. An alignment of 1 is always safe.</p>
4033
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4034<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4035<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4036 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4037 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4038 does not exceed the minimum number of bytes needed to hold all bits of the
4039 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4040 writing a value of a type like <tt>i20</tt> with a size that is not an
4041 integral number of bytes, it is unspecified what happens to the extra bits
4042 that do not belong to the type, but they will typically be overwritten.</p>
4043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4044<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4045<pre>
4046 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4047 store i32 3, i32* %ptr <i>; yields {void}</i>
4048 %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]4049</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051</div>
4052
4053<!-- _______________________________________________________________________ -->
4054<div class="doc_subsubsection">
4055 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4056</div>
4057
4058<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4059
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4060<h5>Syntax:</h5>
4061<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4062 &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]4063 &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]4064</pre>
4065
4066<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4067<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4068 subelement of an aggregate data structure. It performs address calculation
4069 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070
4071<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4072<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4073 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4074 elements of the aggregate object are indexed. The interpretation of each
4075 index is dependent on the type being indexed into. The first index always
4076 indexes the pointer value given as the first argument, the second index
4077 indexes a value of the type pointed to (not necessarily the value directly
4078 pointed to, since the first index can be non-zero), etc. The first type
4079 indexed into must be a pointer value, subsequent types can be arrays, vectors
4080 and structs. Note that subsequent types being indexed into can never be
4081 pointers, since that would require loading the pointer before continuing
4082 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4083
4084<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]4085 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4086 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4087 vector, integers of any width are allowed, and they are not required to be
4088 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4089
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4090<p>For example, let's consider a C code fragment and how it gets compiled to
4091 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4092
4093<div class="doc_code">
4094<pre>
4095struct RT {
4096 char A;
4097 int B[10][20];
4098 char C;
4099};
4100struct ST {
4101 int X;
4102 double Y;
4103 struct RT Z;
4104};
4105
4106int *foo(struct ST *s) {
4107 return &amp;s[1].Z.B[5][13];
4108}
4109</pre>
4110</div>
4111
4112<p>The LLVM code generated by the GCC frontend is:</p>
4113
4114<div class="doc_code">
4115<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4116%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4117%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4118
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4119define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120entry:
4121 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4122 ret i32* %reg
4123}
4124</pre>
4125</div>
4126
4127<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4128<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]4129 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4130 }</tt>' type, a structure. The second index indexes into the third element
4131 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4132 i8 }</tt>' type, another structure. The third index indexes into the second
4133 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4134 array. The two dimensions of the array are subscripted into, yielding an
4135 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4136 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4137
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4138<p>Note that it is perfectly legal to index partially through a structure,
4139 returning a pointer to an inner element. Because of this, the LLVM code for
4140 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141
4142<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4143 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4144 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4145 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4146 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4147 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4148 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4149 ret i32* %t5
4150 }
4151</pre>
4152
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4153<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4154 <tt>getelementptr</tt> is undefined if the base pointer is not an
4155 <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]4156 that would be formed by successive addition of the offsets implied by the
4157 indices to the base address with infinitely precise arithmetic are not an
4158 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4159 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4160 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4161
4162<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4163 the base address with silently-wrapping two's complement arithmetic, and
4164 the result value of the <tt>getelementptr</tt> may be outside the object
4165 pointed to by the base pointer. The result value may not necessarily be
4166 used to access memory though, even if it happens to point into allocated
4167 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4168 section for more information.</p>
4169
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4170<p>The getelementptr instruction is often confusing. For some more insight into
4171 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4172
4173<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4174<pre>
4175 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4176 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4177 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4178 %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]4179 <i>; yields i8*:eptr</i>
4180 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4181 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4182 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4183</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4184
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4185</div>
4186
4187<!-- ======================================================================= -->
4188<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4189</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4191<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4193<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4194 which all take a single operand and a type. They perform various bit
4195 conversions on the operand.</p>
4196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4197</div>
4198
4199<!-- _______________________________________________________________________ -->
4200<div class="doc_subsubsection">
4201 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4202</div>
4203<div class="doc_text">
4204
4205<h5>Syntax:</h5>
4206<pre>
4207 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4208</pre>
4209
4210<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4211<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4212 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4213
4214<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4215<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4216 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4217 size and type of the result, which must be
4218 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4219 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4220 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221
4222<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4223<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4224 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4225 source size must be larger than the destination size, <tt>trunc</tt> cannot
4226 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227
4228<h5>Example:</h5>
4229<pre>
4230 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4231 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4232 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4233</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4234
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4235</div>
4236
4237<!-- _______________________________________________________________________ -->
4238<div class="doc_subsubsection">
4239 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4240</div>
4241<div class="doc_text">
4242
4243<h5>Syntax:</h5>
4244<pre>
4245 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4246</pre>
4247
4248<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4249<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4250 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4251
4252
4253<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4254<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]4255 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4256 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4257 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4258 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4259
4260<h5>Semantics:</h5>
4261<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]4262 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4263
4264<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4265
4266<h5>Example:</h5>
4267<pre>
4268 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4269 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4270</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272</div>
4273
4274<!-- _______________________________________________________________________ -->
4275<div class="doc_subsubsection">
4276 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4277</div>
4278<div class="doc_text">
4279
4280<h5>Syntax:</h5>
4281<pre>
4282 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4283</pre>
4284
4285<h5>Overview:</h5>
4286<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4287
4288<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4289<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4290 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4291 also be of <a href="#t_integer">integer</a> type. The bit size of the
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4292 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4293 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4294
4295<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4296<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4297 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4298 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4299
4300<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4301
4302<h5>Example:</h5>
4303<pre>
4304 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4305 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4306</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4308</div>
4309
4310<!-- _______________________________________________________________________ -->
4311<div class="doc_subsubsection">
4312 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4313</div>
4314
4315<div class="doc_text">
4316
4317<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4318<pre>
4319 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4320</pre>
4321
4322<h5>Overview:</h5>
4323<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4324 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4325
4326<h5>Arguments:</h5>
4327<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4328 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4329 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4330 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4332
4333<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4334<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4335 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4336 <a href="#t_floating">floating point</a> type. If the value cannot fit
4337 within the destination type, <tt>ty2</tt>, then the results are
4338 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4339
4340<h5>Example:</h5>
4341<pre>
4342 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4343 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4344</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4345
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4346</div>
4347
4348<!-- _______________________________________________________________________ -->
4349<div class="doc_subsubsection">
4350 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4351</div>
4352<div class="doc_text">
4353
4354<h5>Syntax:</h5>
4355<pre>
4356 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4357</pre>
4358
4359<h5>Overview:</h5>
4360<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]4361 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4362
4363<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4364<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4365 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4366 a <a href="#t_floating">floating point</a> type to cast it to. The source
4367 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4368
4369<h5>Semantics:</h5>
4370<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4371 <a href="#t_floating">floating point</a> type to a larger
4372 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4373 used to make a <i>no-op cast</i> because it always changes bits. Use
4374 <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]4375
4376<h5>Example:</h5>
4377<pre>
4378 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4379 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4380</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4381
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4382</div>
4383
4384<!-- _______________________________________________________________________ -->
4385<div class="doc_subsubsection">
4386 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4387</div>
4388<div class="doc_text">
4389
4390<h5>Syntax:</h5>
4391<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4392 &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]4393</pre>
4394
4395<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4396<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4397 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4398
4399<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4400<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4401 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4402 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4403 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4404 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4405
4406<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4407<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4408 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4409 towards zero) unsigned integer value. If the value cannot fit
4410 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4412<h5>Example:</h5>
4413<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4414 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4415 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4416 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4417</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4419</div>
4420
4421<!-- _______________________________________________________________________ -->
4422<div class="doc_subsubsection">
4423 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4424</div>
4425<div class="doc_text">
4426
4427<h5>Syntax:</h5>
4428<pre>
4429 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4430</pre>
4431
4432<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4433<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4434 <a href="#t_floating">floating point</a> <tt>value</tt> to
4435 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4437<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4438<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4439 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4440 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4441 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4442 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4443
4444<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4445<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4446 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4447 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4448 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4450<h5>Example:</h5>
4451<pre>
4452 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4453 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4454 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4455</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4456
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4457</div>
4458
4459<!-- _______________________________________________________________________ -->
4460<div class="doc_subsubsection">
4461 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4462</div>
4463<div class="doc_text">
4464
4465<h5>Syntax:</h5>
4466<pre>
4467 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4468</pre>
4469
4470<h5>Overview:</h5>
4471<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4472 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4475<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]4476 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4477 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4478 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4479 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480
4481<h5>Semantics:</h5>
4482<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4483 integer quantity and converts it to the corresponding floating point
4484 value. If the value cannot fit in the floating point value, the results are
4485 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4487<h5>Example:</h5>
4488<pre>
4489 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4490 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4491</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4493</div>
4494
4495<!-- _______________________________________________________________________ -->
4496<div class="doc_subsubsection">
4497 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4498</div>
4499<div class="doc_text">
4500
4501<h5>Syntax:</h5>
4502<pre>
4503 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4504</pre>
4505
4506<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4507<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4508 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4509
4510<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4511<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]4512 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4513 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4514 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4515 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516
4517<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4518<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4519 quantity and converts it to the corresponding floating point value. If the
4520 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4521
4522<h5>Example:</h5>
4523<pre>
4524 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4525 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4526</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4528</div>
4529
4530<!-- _______________________________________________________________________ -->
4531<div class="doc_subsubsection">
4532 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4533</div>
4534<div class="doc_text">
4535
4536<h5>Syntax:</h5>
4537<pre>
4538 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4539</pre>
4540
4541<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4542<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4543 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4544
4545<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4546<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4547 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4548 <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]4549
4550<h5>Semantics:</h5>
4551<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4552 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4553 truncating or zero extending that value to the size of the integer type. If
4554 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4555 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4556 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4557 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4558
4559<h5>Example:</h5>
4560<pre>
4561 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4562 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4563</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4565</div>
4566
4567<!-- _______________________________________________________________________ -->
4568<div class="doc_subsubsection">
4569 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4570</div>
4571<div class="doc_text">
4572
4573<h5>Syntax:</h5>
4574<pre>
4575 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4576</pre>
4577
4578<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4579<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4580 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4581
4582<h5>Arguments:</h5>
4583<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4584 value to cast, and a type to cast it to, which must be a
4585 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4586
4587<h5>Semantics:</h5>
4588<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4589 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4590 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4591 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4592 than the size of a pointer then a zero extension is done. If they are the
4593 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4594
4595<h5>Example:</h5>
4596<pre>
4597 %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]4598 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4599 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4600</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602</div>
4603
4604<!-- _______________________________________________________________________ -->
4605<div class="doc_subsubsection">
4606 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4607</div>
4608<div class="doc_text">
4609
4610<h5>Syntax:</h5>
4611<pre>
4612 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4613</pre>
4614
4615<h5>Overview:</h5>
4616<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4617 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4618
4619<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4620<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4621 non-aggregate first class value, and a type to cast it to, which must also be
4622 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4623 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4624 identical. If the source type is a pointer, the destination type must also be
4625 a pointer. This instruction supports bitwise conversion of vectors to
4626 integers and to vectors of other types (as long as they have the same
4627 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4628
4629<h5>Semantics:</h5>
4630<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4631 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4632 this conversion. The conversion is done as if the <tt>value</tt> had been
4633 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4634 be converted to other pointer types with this instruction. To convert
4635 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4636 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4637
4638<h5>Example:</h5>
4639<pre>
4640 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4641 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4642 %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]4643</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4645</div>
4646
4647<!-- ======================================================================= -->
4648<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4650<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4651
4652<p>The instructions in this category are the "miscellaneous" instructions, which
4653 defy better classification.</p>
4654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4655</div>
4656
4657<!-- _______________________________________________________________________ -->
4658<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4659</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4661<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4663<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664<pre>
4665 &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]4666</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4668<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4669<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4670 boolean values based on comparison of its two integer, integer vector, or
4671 pointer operands.</p>
4672
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673<h5>Arguments:</h5>
4674<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4675 the condition code indicating the kind of comparison to perform. It is not a
4676 value, just a keyword. The possible condition code are:</p>
4677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4678<ol>
4679 <li><tt>eq</tt>: equal</li>
4680 <li><tt>ne</tt>: not equal </li>
4681 <li><tt>ugt</tt>: unsigned greater than</li>
4682 <li><tt>uge</tt>: unsigned greater or equal</li>
4683 <li><tt>ult</tt>: unsigned less than</li>
4684 <li><tt>ule</tt>: unsigned less or equal</li>
4685 <li><tt>sgt</tt>: signed greater than</li>
4686 <li><tt>sge</tt>: signed greater or equal</li>
4687 <li><tt>slt</tt>: signed less than</li>
4688 <li><tt>sle</tt>: signed less or equal</li>
4689</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4692 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4693 typed. They must also be identical types.</p>
4694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4695<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4696<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4697 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4698 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]4699 result, as follows:</p>
4700
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4701<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4702 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4703 <tt>false</tt> otherwise. No sign interpretation is necessary or
4704 performed.</li>
4705
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4706 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4707 <tt>false</tt> otherwise. No sign interpretation is necessary or
4708 performed.</li>
4709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4710 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4711 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4713 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4714 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4715 to <tt>op2</tt>.</li>
4716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4717 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4718 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4724 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4728 to <tt>op2</tt>.</li>
4729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4730 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4731 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4733 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4734 <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]4735</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4737<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4738 values are compared as if they were integers.</p>
4739
4740<p>If the operands are integer vectors, then they are compared element by
4741 element. The result is an <tt>i1</tt> vector with the same number of elements
4742 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4743
4744<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4745<pre>
4746 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4747 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4748 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4749 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4750 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4751 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4752</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4753
4754<p>Note that the code generator does not yet support vector types with
4755 the <tt>icmp</tt> instruction.</p>
4756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757</div>
4758
4759<!-- _______________________________________________________________________ -->
4760<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4761</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4765<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4766<pre>
4767 &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]4768</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4770<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4771<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4772 values based on comparison of its operands.</p>
4773
4774<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]4775(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4776
4777<p>If the operands are floating point vectors, then the result type is a vector
4778 of boolean with the same number of elements as the operands being
4779 compared.</p>
4780
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4781<h5>Arguments:</h5>
4782<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4783 the condition code indicating the kind of comparison to perform. It is not a
4784 value, just a keyword. The possible condition code are:</p>
4785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4786<ol>
4787 <li><tt>false</tt>: no comparison, always returns false</li>
4788 <li><tt>oeq</tt>: ordered and equal</li>
4789 <li><tt>ogt</tt>: ordered and greater than </li>
4790 <li><tt>oge</tt>: ordered and greater than or equal</li>
4791 <li><tt>olt</tt>: ordered and less than </li>
4792 <li><tt>ole</tt>: ordered and less than or equal</li>
4793 <li><tt>one</tt>: ordered and not equal</li>
4794 <li><tt>ord</tt>: ordered (no nans)</li>
4795 <li><tt>ueq</tt>: unordered or equal</li>
4796 <li><tt>ugt</tt>: unordered or greater than </li>
4797 <li><tt>uge</tt>: unordered or greater than or equal</li>
4798 <li><tt>ult</tt>: unordered or less than </li>
4799 <li><tt>ule</tt>: unordered or less than or equal</li>
4800 <li><tt>une</tt>: unordered or not equal</li>
4801 <li><tt>uno</tt>: unordered (either nans)</li>
4802 <li><tt>true</tt>: no comparison, always returns true</li>
4803</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4804
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4805<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4806 <i>unordered</i> means that either operand may be a QNAN.</p>
4807
4808<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4809 a <a href="#t_floating">floating point</a> type or
4810 a <a href="#t_vector">vector</a> of floating point type. They must have
4811 identical types.</p>
4812
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4813<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4814<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4815 according to the condition code given as <tt>cond</tt>. If the operands are
4816 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4817 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4818 follows:</p>
4819
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4820<ol>
4821 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4822
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4823 <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]4824 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4826 <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]4827 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4828
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4829 <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]4830 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4831
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4832 <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]4833 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4834
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4835 <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]4836 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4837
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4838 <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]4839 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4841 <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]4842
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4843 <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]4844 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4845
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4846 <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]4847 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4848
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4849 <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]4850 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4851
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4852 <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]4853 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4854
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4855 <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]4856 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4857
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4858 <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]4859 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4860
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4861 <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]4862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4864</ol>
4865
4866<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4867<pre>
4868 &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]4869 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4870 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4871 &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]4872</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4873
4874<p>Note that the code generator does not yet support vector types with
4875 the <tt>fcmp</tt> instruction.</p>
4876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4877</div>
4878
4879<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4880<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4881 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4882</div>
4883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4885
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4886<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4887<pre>
4888 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4889</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4891<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4892<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4893 SSA graph representing the function.</p>
4894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4895<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4896<p>The type of the incoming values is specified with the first type field. After
4897 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4898 one pair for each predecessor basic block of the current block. Only values
4899 of <a href="#t_firstclass">first class</a> type may be used as the value
4900 arguments to the PHI node. Only labels may be used as the label
4901 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4903<p>There must be no non-phi instructions between the start of a basic block and
4904 the PHI instructions: i.e. PHI instructions must be first in a basic
4905 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4906
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4907<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4908 occur on the edge from the corresponding predecessor block to the current
4909 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4910 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4912<h5>Semantics:</h5>
4913<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4914 specified by the pair corresponding to the predecessor basic block that
4915 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4917<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4918<pre>
4919Loop: ; Infinite loop that counts from 0 on up...
4920 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4921 %nextindvar = add i32 %indvar, 1
4922 br label %Loop
4923</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4925</div>
4926
4927<!-- _______________________________________________________________________ -->
4928<div class="doc_subsubsection">
4929 <a name="i_select">'<tt>select</tt>' Instruction</a>
4930</div>
4931
4932<div class="doc_text">
4933
4934<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4935<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4936 &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>
4937
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4938 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4939</pre>
4940
4941<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4942<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4943 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4944
4945
4946<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4947<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4948 values indicating the condition, and two values of the
4949 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4950 vectors and the condition is a scalar, then entire vectors are selected, not
4951 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4952
4953<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4954<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4955 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4956
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4957<p>If the condition is a vector of i1, then the value arguments must be vectors
4958 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4959
4960<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4961<pre>
4962 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4963</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4964
4965<p>Note that the code generator does not yet support conditions
4966 with vector type.</p>
4967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4968</div>
4969
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4970<!-- _______________________________________________________________________ -->
4971<div class="doc_subsubsection">
4972 <a name="i_call">'<tt>call</tt>' Instruction</a>
4973</div>
4974
4975<div class="doc_text">
4976
4977<h5>Syntax:</h5>
4978<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4979 &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]4980</pre>
4981
4982<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4983<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4984
4985<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4986<p>This instruction requires several arguments:</p>
4987
4988<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4989 <li>The optional "tail" marker indicates whether the callee function accesses
4990 any allocas or varargs in the caller. If the "tail" marker is present,
4991 the function call is eligible for tail call optimization. Note that calls
4992 may be marked "tail" even if they do not occur before
4993 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4994
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4995 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4996 convention</a> the call should use. If none is specified, the call
4997 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4998
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4999 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5000 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5001 '<tt>inreg</tt>' attributes are valid here.</li>
5002
5003 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5004 type of the return value. Functions that return no value are marked
5005 <tt><a href="#t_void">void</a></tt>.</li>
5006
5007 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5008 being invoked. The argument types must match the types implied by this
5009 signature. This type can be omitted if the function is not varargs and if
5010 the function type does not return a pointer to a function.</li>
5011
5012 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5013 be invoked. In most cases, this is a direct function invocation, but
5014 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5015 to function value.</li>
5016
5017 <li>'<tt>function args</tt>': argument list whose types match the function
5018 signature argument types. All arguments must be of
5019 <a href="#t_firstclass">first class</a> type. If the function signature
5020 indicates the function accepts a variable number of arguments, the extra
5021 arguments can be specified.</li>
5022
5023 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5024 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5025 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5026</ol>
5027
5028<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5029<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5030 a specified function, with its incoming arguments bound to the specified
5031 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5032 function, control flow continues with the instruction after the function
5033 call, and the return value of the function is bound to the result
5034 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5035
5036<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5037<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5038 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5039 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5040 %X = tail call i32 @foo() <i>; yields i32</i>
5041 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5042 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5043
5044 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5045 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5046 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5047 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5048 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5049 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5050</pre>
5051
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5052<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5053standard C99 library as being the C99 library functions, and may perform
5054optimizations or generate code for them under that assumption. This is
5055something we'd like to change in the future to provide better support for
5056freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5057
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5058</div>
5059
5060<!-- _______________________________________________________________________ -->
5061<div class="doc_subsubsection">
5062 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5063</div>
5064
5065<div class="doc_text">
5066
5067<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5068<pre>
5069 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5070</pre>
5071
5072<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5073<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5074 the "variable argument" area of a function call. It is used to implement the
5075 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5076
5077<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5078<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5079 argument. It returns a value of the specified argument type and increments
5080 the <tt>va_list</tt> to point to the next argument. The actual type
5081 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5082
5083<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5084<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5085 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5086 to the next argument. For more information, see the variable argument
5087 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088
5089<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]5090 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5091 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5093<p><tt>va_arg</tt> is an LLVM instruction instead of
5094 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5095 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5096
5097<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5098<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5099
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5100<p>Note that the code generator does not yet fully support va_arg on many
5101 targets. Also, it does not currently support va_arg with aggregate types on
5102 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5103
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5104</div>
5105
5106<!-- *********************************************************************** -->
5107<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5108<!-- *********************************************************************** -->
5109
5110<div class="doc_text">
5111
5112<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5113 well known names and semantics and are required to follow certain
5114 restrictions. Overall, these intrinsics represent an extension mechanism for
5115 the LLVM language that does not require changing all of the transformations
5116 in LLVM when adding to the language (or the bitcode reader/writer, the
5117 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5118
5119<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5120 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5121 begin with this prefix. Intrinsic functions must always be external
5122 functions: you cannot define the body of intrinsic functions. Intrinsic
5123 functions may only be used in call or invoke instructions: it is illegal to
5124 take the address of an intrinsic function. Additionally, because intrinsic
5125 functions are part of the LLVM language, it is required if any are added that
5126 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5127
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5128<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5129 family of functions that perform the same operation but on different data
5130 types. Because LLVM can represent over 8 million different integer types,
5131 overloading is used commonly to allow an intrinsic function to operate on any
5132 integer type. One or more of the argument types or the result type can be
5133 overloaded to accept any integer type. Argument types may also be defined as
5134 exactly matching a previous argument's type or the result type. This allows
5135 an intrinsic function which accepts multiple arguments, but needs all of them
5136 to be of the same type, to only be overloaded with respect to a single
5137 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5138
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5139<p>Overloaded intrinsics will have the names of its overloaded argument types
5140 encoded into its function name, each preceded by a period. Only those types
5141 which are overloaded result in a name suffix. Arguments whose type is matched
5142 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5143 can take an integer of any width and returns an integer of exactly the same
5144 integer width. This leads to a family of functions such as
5145 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5146 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5147 suffix is required. Because the argument's type is matched against the return
5148 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5149
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5150<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5151 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5152
5153</div>
5154
5155<!-- ======================================================================= -->
5156<div class="doc_subsection">
5157 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5158</div>
5159
5160<div class="doc_text">
5161
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5162<p>Variable argument support is defined in LLVM with
5163 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5164 intrinsic functions. These functions are related to the similarly named
5165 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5166
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5167<p>All of these functions operate on arguments that use a target-specific value
5168 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5169 not define what this type is, so all transformations should be prepared to
5170 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5171
5172<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]5173 instruction and the variable argument handling intrinsic functions are
5174 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5175
5176<div class="doc_code">
5177<pre>
5178define i32 @test(i32 %X, ...) {
5179 ; Initialize variable argument processing
5180 %ap = alloca i8*
5181 %ap2 = bitcast i8** %ap to i8*
5182 call void @llvm.va_start(i8* %ap2)
5183
5184 ; Read a single integer argument
5185 %tmp = va_arg i8** %ap, i32
5186
5187 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5188 %aq = alloca i8*
5189 %aq2 = bitcast i8** %aq to i8*
5190 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5191 call void @llvm.va_end(i8* %aq2)
5192
5193 ; Stop processing of arguments.
5194 call void @llvm.va_end(i8* %ap2)
5195 ret i32 %tmp
5196}
5197
5198declare void @llvm.va_start(i8*)
5199declare void @llvm.va_copy(i8*, i8*)
5200declare void @llvm.va_end(i8*)
5201</pre>
5202</div>
5203
5204</div>
5205
5206<!-- _______________________________________________________________________ -->
5207<div class="doc_subsubsection">
5208 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5209</div>
5210
5211
5212<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5213
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5214<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5215<pre>
5216 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5217</pre>
5218
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5219<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5220<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5221 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]5222
5223<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5224<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]5225
5226<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5227<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]5228 macro available in C. In a target-dependent way, it initializes
5229 the <tt>va_list</tt> element to which the argument points, so that the next
5230 call to <tt>va_arg</tt> will produce the first variable argument passed to
5231 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5232 need to know the last argument of the function as the compiler can figure
5233 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5234
5235</div>
5236
5237<!-- _______________________________________________________________________ -->
5238<div class="doc_subsubsection">
5239 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5240</div>
5241
5242<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5243
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5244<h5>Syntax:</h5>
5245<pre>
5246 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5247</pre>
5248
5249<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5250<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5251 which has been initialized previously
5252 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5253 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5254
5255<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5256<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5257
5258<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5259<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]5260 macro available in C. In a target-dependent way, it destroys
5261 the <tt>va_list</tt> element to which the argument points. Calls
5262 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5263 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5264 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5265
5266</div>
5267
5268<!-- _______________________________________________________________________ -->
5269<div class="doc_subsubsection">
5270 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5271</div>
5272
5273<div class="doc_text">
5274
5275<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5276<pre>
5277 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5278</pre>
5279
5280<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5281<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5282 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5283
5284<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285<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]5286 The second argument is a pointer to a <tt>va_list</tt> element to copy
5287 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5288
5289<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5290<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]5291 macro available in C. In a target-dependent way, it copies the
5292 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5293 element. This intrinsic is necessary because
5294 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5295 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5296
5297</div>
5298
5299<!-- ======================================================================= -->
5300<div class="doc_subsection">
5301 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5302</div>
5303
5304<div class="doc_text">
5305
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5306<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5307Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5308intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5309roots on the stack</a>, as well as garbage collector implementations that
5310require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5311barriers. Front-ends for type-safe garbage collected languages should generate
5312these intrinsics to make use of the LLVM garbage collectors. For more details,
5313see <a href="GarbageCollection.html">Accurate Garbage Collection with
5314LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5315
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5316<p>The garbage collection intrinsics only operate on objects in the generic
5317 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5319</div>
5320
5321<!-- _______________________________________________________________________ -->
5322<div class="doc_subsubsection">
5323 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5324</div>
5325
5326<div class="doc_text">
5327
5328<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5329<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5330 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5331</pre>
5332
5333<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5334<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]5335 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5336
5337<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5338<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5339 root pointer. The second pointer (which must be either a constant or a
5340 global value address) contains the meta-data to be associated with the
5341 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5342
5343<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5344<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]5345 location. At compile-time, the code generator generates information to allow
5346 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5347 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5348 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5349
5350</div>
5351
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5352<!-- _______________________________________________________________________ -->
5353<div class="doc_subsubsection">
5354 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5355</div>
5356
5357<div class="doc_text">
5358
5359<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5360<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5361 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5362</pre>
5363
5364<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5365<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5366 locations, allowing garbage collector implementations that require read
5367 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5368
5369<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5370<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]5371 allocated from the garbage collector. The first object is a pointer to the
5372 start of the referenced object, if needed by the language runtime (otherwise
5373 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5374
5375<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5376<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5377 instruction, but may be replaced with substantially more complex code by the
5378 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5379 may only be used in a function which <a href="#gc">specifies a GC
5380 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5381
5382</div>
5383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384<!-- _______________________________________________________________________ -->
5385<div class="doc_subsubsection">
5386 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5387</div>
5388
5389<div class="doc_text">
5390
5391<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5392<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5393 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5394</pre>
5395
5396<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5397<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5398 locations, allowing garbage collector implementations that require write
5399 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400
5401<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5402<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]5403 object to store it to, and the third is the address of the field of Obj to
5404 store to. If the runtime does not require a pointer to the object, Obj may
5405 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406
5407<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5408<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5409 instruction, but may be replaced with substantially more complex code by the
5410 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5411 may only be used in a function which <a href="#gc">specifies a GC
5412 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5413
5414</div>
5415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5416<!-- ======================================================================= -->
5417<div class="doc_subsection">
5418 <a name="int_codegen">Code Generator Intrinsics</a>
5419</div>
5420
5421<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5422
5423<p>These intrinsics are provided by LLVM to expose special features that may
5424 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5425
5426</div>
5427
5428<!-- _______________________________________________________________________ -->
5429<div class="doc_subsubsection">
5430 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5431</div>
5432
5433<div class="doc_text">
5434
5435<h5>Syntax:</h5>
5436<pre>
5437 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5438</pre>
5439
5440<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5441<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5442 target-specific value indicating the return address of the current function
5443 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5444
5445<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5446<p>The argument to this intrinsic indicates which function to return the address
5447 for. Zero indicates the calling function, one indicates its caller, etc.
5448 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5449
5450<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5451<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5452 indicating the return address of the specified call frame, or zero if it
5453 cannot be identified. The value returned by this intrinsic is likely to be
5454 incorrect or 0 for arguments other than zero, so it should only be used for
5455 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5456
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5457<p>Note that calling this intrinsic does not prevent function inlining or other
5458 aggressive transformations, so the value returned may not be that of the
5459 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461</div>
5462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463<!-- _______________________________________________________________________ -->
5464<div class="doc_subsubsection">
5465 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5466</div>
5467
5468<div class="doc_text">
5469
5470<h5>Syntax:</h5>
5471<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5472 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473</pre>
5474
5475<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5476<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5477 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5478
5479<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5480<p>The argument to this intrinsic indicates which function to return the frame
5481 pointer for. Zero indicates the calling function, one indicates its caller,
5482 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5483
5484<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5485<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5486 indicating the frame address of the specified call frame, or zero if it
5487 cannot be identified. The value returned by this intrinsic is likely to be
5488 incorrect or 0 for arguments other than zero, so it should only be used for
5489 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5490
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5491<p>Note that calling this intrinsic does not prevent function inlining or other
5492 aggressive transformations, so the value returned may not be that of the
5493 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5495</div>
5496
5497<!-- _______________________________________________________________________ -->
5498<div class="doc_subsubsection">
5499 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5500</div>
5501
5502<div class="doc_text">
5503
5504<h5>Syntax:</h5>
5505<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5506 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5507</pre>
5508
5509<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5510<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5511 of the function stack, for use
5512 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5513 useful for implementing language features like scoped automatic variable
5514 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5515
5516<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5517<p>This intrinsic returns a opaque pointer value that can be passed
5518 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5519 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5520 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5521 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5522 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5523 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5524
5525</div>
5526
5527<!-- _______________________________________________________________________ -->
5528<div class="doc_subsubsection">
5529 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5530</div>
5531
5532<div class="doc_text">
5533
5534<h5>Syntax:</h5>
5535<pre>
5536 declare void @llvm.stackrestore(i8 * %ptr)
5537</pre>
5538
5539<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5540<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5541 the function stack to the state it was in when the
5542 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5543 executed. This is useful for implementing language features like scoped
5544 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5545
5546<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5547<p>See the description
5548 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549
5550</div>
5551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5552<!-- _______________________________________________________________________ -->
5553<div class="doc_subsubsection">
5554 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5555</div>
5556
5557<div class="doc_text">
5558
5559<h5>Syntax:</h5>
5560<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5561 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]5562</pre>
5563
5564<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5565<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5566 insert a prefetch instruction if supported; otherwise, it is a noop.
5567 Prefetches have no effect on the behavior of the program but can change its
5568 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5569
5570<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5571<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5572 specifier determining if the fetch should be for a read (0) or write (1),
5573 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5574 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5575 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5576
5577<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5578<p>This intrinsic does not modify the behavior of the program. In particular,
5579 prefetches cannot trap and do not produce a value. On targets that support
5580 this intrinsic, the prefetch can provide hints to the processor cache for
5581 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5582
5583</div>
5584
5585<!-- _______________________________________________________________________ -->
5586<div class="doc_subsubsection">
5587 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5588</div>
5589
5590<div class="doc_text">
5591
5592<h5>Syntax:</h5>
5593<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5594 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5595</pre>
5596
5597<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5598<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5599 Counter (PC) in a region of code to simulators and other tools. The method
5600 is target specific, but it is expected that the marker will use exported
5601 symbols to transmit the PC of the marker. The marker makes no guarantees
5602 that it will remain with any specific instruction after optimizations. It is
5603 possible that the presence of a marker will inhibit optimizations. The
5604 intended use is to be inserted after optimizations to allow correlations of
5605 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5606
5607<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5608<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5609
5610<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5611<p>This intrinsic does not modify the behavior of the program. Backends that do
5612 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5613
5614</div>
5615
5616<!-- _______________________________________________________________________ -->
5617<div class="doc_subsubsection">
5618 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5619</div>
5620
5621<div class="doc_text">
5622
5623<h5>Syntax:</h5>
5624<pre>
5625 declare i64 @llvm.readcyclecounter( )
5626</pre>
5627
5628<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5629<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5630 counter register (or similar low latency, high accuracy clocks) on those
5631 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5632 should map to RPCC. As the backing counters overflow quickly (on the order
5633 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634
5635<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5636<p>When directly supported, reading the cycle counter should not modify any
5637 memory. Implementations are allowed to either return a application specific
5638 value or a system wide value. On backends without support, this is lowered
5639 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5640
5641</div>
5642
5643<!-- ======================================================================= -->
5644<div class="doc_subsection">
5645 <a name="int_libc">Standard C Library Intrinsics</a>
5646</div>
5647
5648<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5649
5650<p>LLVM provides intrinsics for a few important standard C library functions.
5651 These intrinsics allow source-language front-ends to pass information about
5652 the alignment of the pointer arguments to the code generator, providing
5653 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5654
5655</div>
5656
5657<!-- _______________________________________________________________________ -->
5658<div class="doc_subsubsection">
5659 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5660</div>
5661
5662<div class="doc_text">
5663
5664<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5665<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5666 integer bit width. Not all targets support all bit widths however.</p>
5667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5668<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5669 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5670 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5671 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5672 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5673 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5674 i32 &lt;len&gt;, i32 &lt;align&gt;)
5675 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5676 i64 &lt;len&gt;, i32 &lt;align&gt;)
5677</pre>
5678
5679<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5680<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5681 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5682
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5683<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5684 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685
5686<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5687<p>The first argument is a pointer to the destination, the second is a pointer
5688 to the source. The third argument is an integer argument specifying the
5689 number of bytes to copy, and the fourth argument is the alignment of the
5690 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5691
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5692<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5693 then the caller guarantees that both the source and destination pointers are
5694 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695
5696<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5697<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5698 source location to the destination location, which are not allowed to
5699 overlap. It copies "len" bytes of memory over. If the argument is known to
5700 be aligned to some boundary, this can be specified as the fourth argument,
5701 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5703</div>
5704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5705<!-- _______________________________________________________________________ -->
5706<div class="doc_subsubsection">
5707 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5708</div>
5709
5710<div class="doc_text">
5711
5712<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5713<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5714 width. Not all targets support all bit widths however.</p>
5715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5717 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5719 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5720 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5721 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5722 i32 &lt;len&gt;, i32 &lt;align&gt;)
5723 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5724 i64 &lt;len&gt;, i32 &lt;align&gt;)
5725</pre>
5726
5727<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5728<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5729 source location to the destination location. It is similar to the
5730 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5731 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5732
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5733<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5734 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735
5736<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5737<p>The first argument is a pointer to the destination, the second is a pointer
5738 to the source. The third argument is an integer argument specifying the
5739 number of bytes to copy, and the fourth argument is the alignment of the
5740 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5742<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5743 then the caller guarantees that the source and destination pointers are
5744 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5745
5746<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5747<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5748 source location to the destination location, which may overlap. It copies
5749 "len" bytes of memory over. If the argument is known to be aligned to some
5750 boundary, this can be specified as the fourth argument, otherwise it should
5751 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5753</div>
5754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5755<!-- _______________________________________________________________________ -->
5756<div class="doc_subsubsection">
5757 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5758</div>
5759
5760<div class="doc_text">
5761
5762<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5763<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]5764 width. Not all targets support all bit widths however.</p>
5765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5766<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5767 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5768 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5769 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5770 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5771 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5772 i32 &lt;len&gt;, i32 &lt;align&gt;)
5773 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5774 i64 &lt;len&gt;, i32 &lt;align&gt;)
5775</pre>
5776
5777<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5778<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5779 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5780
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5781<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5782 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5783
5784<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5785<p>The first argument is a pointer to the destination to fill, the second is the
5786 byte value to fill it with, the third argument is an integer argument
5787 specifying the number of bytes to fill, and the fourth argument is the known
5788 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5789
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5790<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5791 then the caller guarantees that the destination pointer is aligned to that
5792 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5793
5794<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5795<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5796 at the destination location. If the argument is known to be aligned to some
5797 boundary, this can be specified as the fourth argument, otherwise it should
5798 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5800</div>
5801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5802<!-- _______________________________________________________________________ -->
5803<div class="doc_subsubsection">
5804 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5805</div>
5806
5807<div class="doc_text">
5808
5809<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5810<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5811 floating point or vector of floating point type. Not all targets support all
5812 types however.</p>
5813
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5814<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5815 declare float @llvm.sqrt.f32(float %Val)
5816 declare double @llvm.sqrt.f64(double %Val)
5817 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5818 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5819 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5820</pre>
5821
5822<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5823<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5824 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5825 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5826 behavior for negative numbers other than -0.0 (which allows for better
5827 optimization, because there is no need to worry about errno being
5828 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]5829
5830<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5831<p>The argument and return value are floating point numbers of the same
5832 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5833
5834<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5835<p>This function returns the sqrt of the specified operand if it is a
5836 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5838</div>
5839
5840<!-- _______________________________________________________________________ -->
5841<div class="doc_subsubsection">
5842 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5843</div>
5844
5845<div class="doc_text">
5846
5847<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5848<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5849 floating point or vector of floating point type. Not all targets support all
5850 types however.</p>
5851
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5852<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5853 declare float @llvm.powi.f32(float %Val, i32 %power)
5854 declare double @llvm.powi.f64(double %Val, i32 %power)
5855 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5856 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5857 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5858</pre>
5859
5860<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5861<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5862 specified (positive or negative) power. The order of evaluation of
5863 multiplications is not defined. When a vector of floating point type is
5864 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5865
5866<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5867<p>The second argument is an integer power, and the first is a value to raise to
5868 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5869
5870<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5871<p>This function returns the first value raised to the second power with an
5872 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5874</div>
5875
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5876<!-- _______________________________________________________________________ -->
5877<div class="doc_subsubsection">
5878 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5879</div>
5880
5881<div class="doc_text">
5882
5883<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5884<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5885 floating point or vector of floating point type. Not all targets support all
5886 types however.</p>
5887
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5888<pre>
5889 declare float @llvm.sin.f32(float %Val)
5890 declare double @llvm.sin.f64(double %Val)
5891 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5892 declare fp128 @llvm.sin.f128(fp128 %Val)
5893 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5894</pre>
5895
5896<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5897<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5898
5899<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5900<p>The argument and return value are floating point numbers of the same
5901 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5902
5903<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5904<p>This function returns the sine of the specified operand, returning the same
5905 values as the libm <tt>sin</tt> functions would, and handles error conditions
5906 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5907
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5908</div>
5909
5910<!-- _______________________________________________________________________ -->
5911<div class="doc_subsubsection">
5912 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5913</div>
5914
5915<div class="doc_text">
5916
5917<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5918<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5919 floating point or vector of floating point type. Not all targets support all
5920 types however.</p>
5921
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5922<pre>
5923 declare float @llvm.cos.f32(float %Val)
5924 declare double @llvm.cos.f64(double %Val)
5925 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5926 declare fp128 @llvm.cos.f128(fp128 %Val)
5927 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5928</pre>
5929
5930<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5931<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5932
5933<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5934<p>The argument and return value are floating point numbers of the same
5935 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5936
5937<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5938<p>This function returns the cosine of the specified operand, returning the same
5939 values as the libm <tt>cos</tt> functions would, and handles error conditions
5940 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5941
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5942</div>
5943
5944<!-- _______________________________________________________________________ -->
5945<div class="doc_subsubsection">
5946 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5947</div>
5948
5949<div class="doc_text">
5950
5951<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5952<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5953 floating point or vector of floating point type. Not all targets support all
5954 types however.</p>
5955
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5956<pre>
5957 declare float @llvm.pow.f32(float %Val, float %Power)
5958 declare double @llvm.pow.f64(double %Val, double %Power)
5959 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5960 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5961 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5962</pre>
5963
5964<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5965<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5966 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5967
5968<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5969<p>The second argument is a floating point power, and the first is a value to
5970 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5971
5972<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5973<p>This function returns the first value raised to the second power, returning
5974 the same values as the libm <tt>pow</tt> functions would, and handles error
5975 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5976
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5977</div>
5978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5979<!-- ======================================================================= -->
5980<div class="doc_subsection">
5981 <a name="int_manip">Bit Manipulation Intrinsics</a>
5982</div>
5983
5984<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5985
5986<p>LLVM provides intrinsics for a few important bit manipulation operations.
5987 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5988
5989</div>
5990
5991<!-- _______________________________________________________________________ -->
5992<div class="doc_subsubsection">
5993 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5994</div>
5995
5996<div class="doc_text">
5997
5998<h5>Syntax:</h5>
5999<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6000 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6002<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6003 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6004 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6005 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6006</pre>
6007
6008<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6009<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6010 values with an even number of bytes (positive multiple of 16 bits). These
6011 are useful for performing operations on data that is not in the target's
6012 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013
6014<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6015<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6016 and low byte of the input i16 swapped. Similarly,
6017 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6018 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6019 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6020 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6021 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6022 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6023
6024</div>
6025
6026<!-- _______________________________________________________________________ -->
6027<div class="doc_subsubsection">
6028 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6029</div>
6030
6031<div class="doc_text">
6032
6033<h5>Syntax:</h5>
6034<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]6035 width. Not all targets support all bit widths however.</p>
6036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6037<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6038 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6039 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6040 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6041 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6042 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6043</pre>
6044
6045<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6046<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6047 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6048
6049<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6050<p>The only argument is the value to be counted. The argument may be of any
6051 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6052
6053<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6054<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]6055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6056</div>
6057
6058<!-- _______________________________________________________________________ -->
6059<div class="doc_subsubsection">
6060 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6061</div>
6062
6063<div class="doc_text">
6064
6065<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6066<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6067 integer bit width. Not all targets support all bit widths however.</p>
6068
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6069<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6070 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6071 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6072 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6073 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6074 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6075</pre>
6076
6077<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6078<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6079 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6080
6081<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6082<p>The only argument is the value to be counted. The argument may be of any
6083 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6084
6085<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6086<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6087 zeros in a variable. If the src == 0 then the result is the size in bits of
6088 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6090</div>
6091
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6092<!-- _______________________________________________________________________ -->
6093<div class="doc_subsubsection">
6094 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6095</div>
6096
6097<div class="doc_text">
6098
6099<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6100<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6101 integer bit width. Not all targets support all bit widths however.</p>
6102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6103<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6104 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6105 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6106 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6107 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6108 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6109</pre>
6110
6111<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6112<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6113 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6114
6115<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6116<p>The only argument is the value to be counted. The argument may be of any
6117 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6118
6119<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6120<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6121 zeros in a variable. If the src == 0 then the result is the size in bits of
6122 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6124</div>
6125
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6126<!-- ======================================================================= -->
6127<div class="doc_subsection">
6128 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6129</div>
6130
6131<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6132
6133<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6134
6135</div>
6136
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6137<!-- _______________________________________________________________________ -->
6138<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6139 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6140</div>
6141
6142<div class="doc_text">
6143
6144<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6145<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]6146 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6147
6148<pre>
6149 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6150 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6151 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6152</pre>
6153
6154<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6155<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6156 a signed addition of the two arguments, and indicate whether an overflow
6157 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6158
6159<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6160<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]6161 be of integer types of any bit width, but they must have the same bit
6162 width. The second element of the result structure must be of
6163 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6164 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6165
6166<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6167<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6168 a signed addition of the two variables. They return a structure &mdash; the
6169 first element of which is the signed summation, and the second element of
6170 which is a bit specifying if the signed summation resulted in an
6171 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6172
6173<h5>Examples:</h5>
6174<pre>
6175 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6176 %sum = extractvalue {i32, i1} %res, 0
6177 %obit = extractvalue {i32, i1} %res, 1
6178 br i1 %obit, label %overflow, label %normal
6179</pre>
6180
6181</div>
6182
6183<!-- _______________________________________________________________________ -->
6184<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6185 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6186</div>
6187
6188<div class="doc_text">
6189
6190<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6191<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]6192 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6193
6194<pre>
6195 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6196 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6197 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6198</pre>
6199
6200<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6201<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6202 an unsigned addition of the two arguments, and indicate whether a carry
6203 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6204
6205<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6206<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]6207 be of integer types of any bit width, but they must have the same bit
6208 width. The second element of the result structure must be of
6209 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6210 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6211
6212<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6213<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6214 an unsigned addition of the two arguments. They return a structure &mdash;
6215 the first element of which is the sum, and the second element of which is a
6216 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6217
6218<h5>Examples:</h5>
6219<pre>
6220 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6221 %sum = extractvalue {i32, i1} %res, 0
6222 %obit = extractvalue {i32, i1} %res, 1
6223 br i1 %obit, label %carry, label %normal
6224</pre>
6225
6226</div>
6227
6228<!-- _______________________________________________________________________ -->
6229<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6230 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6231</div>
6232
6233<div class="doc_text">
6234
6235<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6236<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]6237 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6238
6239<pre>
6240 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6241 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6242 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6243</pre>
6244
6245<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6246<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6247 a signed subtraction of the two arguments, and indicate whether an overflow
6248 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6249
6250<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6251<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]6252 be of integer types of any bit width, but they must have the same bit
6253 width. The second element of the result structure must be of
6254 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6255 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6256
6257<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6258<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6259 a signed subtraction of the two arguments. They return a structure &mdash;
6260 the first element of which is the subtraction, and the second element of
6261 which is a bit specifying if the signed subtraction resulted in an
6262 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6263
6264<h5>Examples:</h5>
6265<pre>
6266 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6267 %sum = extractvalue {i32, i1} %res, 0
6268 %obit = extractvalue {i32, i1} %res, 1
6269 br i1 %obit, label %overflow, label %normal
6270</pre>
6271
6272</div>
6273
6274<!-- _______________________________________________________________________ -->
6275<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6276 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6277</div>
6278
6279<div class="doc_text">
6280
6281<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6282<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]6283 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6284
6285<pre>
6286 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6287 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6288 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6289</pre>
6290
6291<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6292<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6293 an unsigned subtraction of the two arguments, and indicate whether an
6294 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6295
6296<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6297<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]6298 be of integer types of any bit width, but they must have the same bit
6299 width. The second element of the result structure must be of
6300 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6301 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6302
6303<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6304<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6305 an unsigned subtraction of the two arguments. They return a structure &mdash;
6306 the first element of which is the subtraction, and the second element of
6307 which is a bit specifying if the unsigned subtraction resulted in an
6308 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6309
6310<h5>Examples:</h5>
6311<pre>
6312 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6313 %sum = extractvalue {i32, i1} %res, 0
6314 %obit = extractvalue {i32, i1} %res, 1
6315 br i1 %obit, label %overflow, label %normal
6316</pre>
6317
6318</div>
6319
6320<!-- _______________________________________________________________________ -->
6321<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6322 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6323</div>
6324
6325<div class="doc_text">
6326
6327<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6328<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]6329 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6330
6331<pre>
6332 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6333 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6334 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6335</pre>
6336
6337<h5>Overview:</h5>
6338
6339<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6340 a signed multiplication of the two arguments, and indicate whether an
6341 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6342
6343<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6344<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]6345 be of integer types of any bit width, but they must have the same bit
6346 width. The second element of the result structure must be of
6347 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6348 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6349
6350<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6351<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6352 a signed multiplication of the two arguments. They return a structure &mdash;
6353 the first element of which is the multiplication, and the second element of
6354 which is a bit specifying if the signed multiplication resulted in an
6355 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6356
6357<h5>Examples:</h5>
6358<pre>
6359 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6360 %sum = extractvalue {i32, i1} %res, 0
6361 %obit = extractvalue {i32, i1} %res, 1
6362 br i1 %obit, label %overflow, label %normal
6363</pre>
6364
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6365</div>
6366
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6367<!-- _______________________________________________________________________ -->
6368<div class="doc_subsubsection">
6369 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6370</div>
6371
6372<div class="doc_text">
6373
6374<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6375<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]6376 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6377
6378<pre>
6379 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6380 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6381 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6382</pre>
6383
6384<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6385<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6386 a unsigned multiplication of the two arguments, and indicate whether an
6387 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6388
6389<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6390<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]6391 be of integer types of any bit width, but they must have the same bit
6392 width. The second element of the result structure must be of
6393 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6394 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6395
6396<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6397<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6398 an unsigned multiplication of the two arguments. They return a structure
6399 &mdash; the first element of which is the multiplication, and the second
6400 element of which is a bit specifying if the unsigned multiplication resulted
6401 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6402
6403<h5>Examples:</h5>
6404<pre>
6405 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6406 %sum = extractvalue {i32, i1} %res, 0
6407 %obit = extractvalue {i32, i1} %res, 1
6408 br i1 %obit, label %overflow, label %normal
6409</pre>
6410
6411</div>
6412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6413<!-- ======================================================================= -->
6414<div class="doc_subsection">
6415 <a name="int_debugger">Debugger Intrinsics</a>
6416</div>
6417
6418<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6419
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6420<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6421 prefix), are described in
6422 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6423 Level Debugging</a> document.</p>
6424
6425</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6426
6427<!-- ======================================================================= -->
6428<div class="doc_subsection">
6429 <a name="int_eh">Exception Handling Intrinsics</a>
6430</div>
6431
6432<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6433
6434<p>The LLVM exception handling intrinsics (which all start with
6435 <tt>llvm.eh.</tt> prefix), are described in
6436 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6437 Handling</a> document.</p>
6438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6439</div>
6440
6441<!-- ======================================================================= -->
6442<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6443 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6444</div>
6445
6446<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6447
6448<p>This intrinsic makes it possible to excise one parameter, marked with
6449 the <tt>nest</tt> attribute, from a function. The result is a callable
6450 function pointer lacking the nest parameter - the caller does not need to
6451 provide a value for it. Instead, the value to use is stored in advance in a
6452 "trampoline", a block of memory usually allocated on the stack, which also
6453 contains code to splice the nest value into the argument list. This is used
6454 to implement the GCC nested function address extension.</p>
6455
6456<p>For example, if the function is
6457 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6458 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6459 follows:</p>
6460
6461<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6462<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6463 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6464 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6465 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6466 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6467</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6468</div>
6469
6470<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6471 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6472
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6473</div>
6474
6475<!-- _______________________________________________________________________ -->
6476<div class="doc_subsubsection">
6477 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6478</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6479
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6480<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6481
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6482<h5>Syntax:</h5>
6483<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6484 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]6485</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6486
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6487<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6488<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6489 function pointer suitable for executing it.</p>
6490
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6491<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6492<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6493 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6494 sufficiently aligned block of memory; this memory is written to by the
6495 intrinsic. Note that the size and the alignment are target-specific - LLVM
6496 currently provides no portable way of determining them, so a front-end that
6497 generates this intrinsic needs to have some target-specific knowledge.
6498 The <tt>func</tt> argument must hold a function bitcast to
6499 an <tt>i8*</tt>.</p>
6500
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6501<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6502<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6503 dependent code, turning it into a function. A pointer to this function is
6504 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6505 function pointer type</a> before being called. The new function's signature
6506 is the same as that of <tt>func</tt> with any arguments marked with
6507 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6508 is allowed, and it must be of pointer type. Calling the new function is
6509 equivalent to calling <tt>func</tt> with the same argument list, but
6510 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6511 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6512 by <tt>tramp</tt> is modified, then the effect of any later call to the
6513 returned function pointer is undefined.</p>
6514
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6515</div>
6516
6517<!-- ======================================================================= -->
6518<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6519 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6520</div>
6521
6522<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6523
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6524<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6525 hardware constructs for atomic operations and memory synchronization. This
6526 provides an interface to the hardware, not an interface to the programmer. It
6527 is aimed at a low enough level to allow any programming models or APIs
6528 (Application Programming Interfaces) which need atomic behaviors to map
6529 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6530 hardware provides a "universal IR" for source languages, it also provides a
6531 starting point for developing a "universal" atomic operation and
6532 synchronization IR.</p>
6533
6534<p>These do <em>not</em> form an API such as high-level threading libraries,
6535 software transaction memory systems, atomic primitives, and intrinsic
6536 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6537 application libraries. The hardware interface provided by LLVM should allow
6538 a clean implementation of all of these APIs and parallel programming models.
6539 No one model or paradigm should be selected above others unless the hardware
6540 itself ubiquitously does so.</p>
6541
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6542</div>
6543
6544<!-- _______________________________________________________________________ -->
6545<div class="doc_subsubsection">
6546 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6547</div>
6548<div class="doc_text">
6549<h5>Syntax:</h5>
6550<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6551 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]6552</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6553
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6554<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6555<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6556 specific pairs of memory access types.</p>
6557
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6558<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6559<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6560 The first four arguments enables a specific barrier as listed below. The
6561 fith argument specifies that the barrier applies to io or device or uncached
6562 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6563
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6564<ul>
6565 <li><tt>ll</tt>: load-load barrier</li>
6566 <li><tt>ls</tt>: load-store barrier</li>
6567 <li><tt>sl</tt>: store-load barrier</li>
6568 <li><tt>ss</tt>: store-store barrier</li>
6569 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6570</ul>
6571
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6572<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6573<p>This intrinsic causes the system to enforce some ordering constraints upon
6574 the loads and stores of the program. This barrier does not
6575 indicate <em>when</em> any events will occur, it only enforces
6576 an <em>order</em> in which they occur. For any of the specified pairs of load
6577 and store operations (f.ex. load-load, or store-load), all of the first
6578 operations preceding the barrier will complete before any of the second
6579 operations succeeding the barrier begin. Specifically the semantics for each
6580 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6581
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6582<ul>
6583 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6584 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6585 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6586 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6587 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6588 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6589 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6590 load after the barrier begins.</li>
6591</ul>
6592
6593<p>These semantics are applied with a logical "and" behavior when more than one
6594 is enabled in a single memory barrier intrinsic.</p>
6595
6596<p>Backends may implement stronger barriers than those requested when they do
6597 not support as fine grained a barrier as requested. Some architectures do
6598 not need all types of barriers and on such architectures, these become
6599 noops.</p>
6600
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6601<h5>Example:</h5>
6602<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6603%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6604%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6605 store i32 4, %ptr
6606
6607%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6608 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6609 <i>; guarantee the above finishes</i>
6610 store i32 8, %ptr <i>; before this begins</i>
6611</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6612
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6613</div>
6614
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6615<!-- _______________________________________________________________________ -->
6616<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6617 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6618</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6619
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6620<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6621
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6622<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6623<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6624 any integer bit width and for different address spaces. Not all targets
6625 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6626
6627<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6628 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6629 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6630 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6631 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]6632</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6633
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6634<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6635<p>This loads a value in memory and compares it to a given value. If they are
6636 equal, it stores a new value into the memory.</p>
6637
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6638<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6639<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6640 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6641 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6642 this integer type. While any bit width integer may be used, targets may only
6643 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6644
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6645<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6646<p>This entire intrinsic must be executed atomically. It first loads the value
6647 in memory pointed to by <tt>ptr</tt> and compares it with the
6648 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6649 memory. The loaded value is yielded in all cases. This provides the
6650 equivalent of an atomic compare-and-swap operation within the SSA
6651 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6652
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6653<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6654<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6655%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6656%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6657 store i32 4, %ptr
6658
6659%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6660%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6661 <i>; yields {i32}:result1 = 4</i>
6662%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6663%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6664
6665%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6666%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6667 <i>; yields {i32}:result2 = 8</i>
6668%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6669
6670%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6671</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6672
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6673</div>
6674
6675<!-- _______________________________________________________________________ -->
6676<div class="doc_subsubsection">
6677 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6678</div>
6679<div class="doc_text">
6680<h5>Syntax:</h5>
6681
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6682<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6683 integer bit width. Not all targets support all bit widths however.</p>
6684
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6685<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6686 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6687 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6688 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6689 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]6690</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6691
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6692<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6693<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6694 the value from memory. It then stores the value in <tt>val</tt> in the memory
6695 at <tt>ptr</tt>.</p>
6696
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6697<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6698<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6699 the <tt>val</tt> argument and the result must be integers of the same bit
6700 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6701 integer type. The targets may only lower integer representations they
6702 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6703
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6704<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6705<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6706 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6707 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6708
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6709<h5>Examples:</h5>
6710<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6711%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6712%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6713 store i32 4, %ptr
6714
6715%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6716%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6717 <i>; yields {i32}:result1 = 4</i>
6718%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6719%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6720
6721%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6722%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6723 <i>; yields {i32}:result2 = 8</i>
6724
6725%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6726%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6727</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6728
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6729</div>
6730
6731<!-- _______________________________________________________________________ -->
6732<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6733 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6734
6735</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6736
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6737<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6738
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6739<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6740<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6741 any integer bit width. Not all targets support all bit widths however.</p>
6742
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6743<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6744 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6745 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6746 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6747 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]6748</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6749
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6750<h5>Overview:</h5>
6751<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6752 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6753
6754<h5>Arguments:</h5>
6755<p>The intrinsic takes two arguments, the first a pointer to an integer value
6756 and the second an integer value. The result is also an integer value. These
6757 integer types can have any bit width, but they must all have the same bit
6758 width. The targets may only lower integer representations they support.</p>
6759
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6760<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6761<p>This intrinsic does a series of operations atomically. It first loads the
6762 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6763 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]6764
6765<h5>Examples:</h5>
6766<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6767%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6768%ptr = bitcast i8* %mallocP to i32*
6769 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6770%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6771 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6772%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6773 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6774%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6775 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6776%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6777</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6778
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6779</div>
6780
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6781<!-- _______________________________________________________________________ -->
6782<div class="doc_subsubsection">
6783 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6784
6785</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6786
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6787<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6788
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6789<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6790<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6791 any integer bit width and for different address spaces. Not all targets
6792 support all bit widths however.</p>
6793
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6794<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6795 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6796 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6797 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6798 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]6799</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6800
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6801<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6802<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6803 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6804
6805<h5>Arguments:</h5>
6806<p>The intrinsic takes two arguments, the first a pointer to an integer value
6807 and the second an integer value. The result is also an integer value. These
6808 integer types can have any bit width, but they must all have the same bit
6809 width. The targets may only lower integer representations they support.</p>
6810
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6811<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6812<p>This intrinsic does a series of operations atomically. It first loads the
6813 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6814 result to <tt>ptr</tt>. It yields the original value stored
6815 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6816
6817<h5>Examples:</h5>
6818<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6819%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6820%ptr = bitcast i8* %mallocP to i32*
6821 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6822%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6823 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6824%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6826%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6827 <i>; yields {i32}:result3 = 2</i>
6828%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6829</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6830
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6831</div>
6832
6833<!-- _______________________________________________________________________ -->
6834<div class="doc_subsubsection">
6835 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6836 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6837 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6838 <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]6839</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6840
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6841<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6842
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6843<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6844<p>These are overloaded intrinsics. You can
6845 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6846 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6847 bit width and for different address spaces. Not all targets support all bit
6848 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6849
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6850<pre>
6851 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6852 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6853 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6854 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]6855</pre>
6856
6857<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6858 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6859 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6860 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6861 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]6862</pre>
6863
6864<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6865 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6866 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6867 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6868 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]6869</pre>
6870
6871<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6872 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6873 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6874 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6875 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]6876</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6877
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6878<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6879<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6880 the value stored in memory at <tt>ptr</tt>. It yields the original value
6881 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6882
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6883<h5>Arguments:</h5>
6884<p>These intrinsics take two arguments, the first a pointer to an integer value
6885 and the second an integer value. The result is also an integer value. These
6886 integer types can have any bit width, but they must all have the same bit
6887 width. The targets may only lower integer representations they support.</p>
6888
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6889<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6890<p>These intrinsics does a series of operations atomically. They first load the
6891 value stored at <tt>ptr</tt>. They then do the bitwise
6892 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6893 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6894
6895<h5>Examples:</h5>
6896<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6897%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6898%ptr = bitcast i8* %mallocP to i32*
6899 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6900%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6901 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6902%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6903 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6904%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6905 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6906%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6907 <i>; yields {i32}:result3 = FF</i>
6908%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6909</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6910
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6911</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6912
6913<!-- _______________________________________________________________________ -->
6914<div class="doc_subsubsection">
6915 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6916 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6917 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6918 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6919</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6920
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6921<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6922
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6923<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6924<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6925 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6926 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6927 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6929<pre>
6930 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6931 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6932 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6933 declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6934</pre>
6935
6936<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6937 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6938 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6939 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6940 declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6941</pre>
6942
6943<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6944 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6945 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6946 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6947 declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6948</pre>
6949
6950<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6951 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6952 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6953 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6954 declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6955</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6956
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6957<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6958<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6959 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6960 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6961
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6962<h5>Arguments:</h5>
6963<p>These intrinsics take two arguments, the first a pointer to an integer value
6964 and the second an integer value. The result is also an integer value. These
6965 integer types can have any bit width, but they must all have the same bit
6966 width. The targets may only lower integer representations they support.</p>
6967
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6968<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6969<p>These intrinsics does a series of operations atomically. They first load the
6970 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6971 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6972 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6973
6974<h5>Examples:</h5>
6975<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6976%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6977%ptr = bitcast i8* %mallocP to i32*
6978 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6979%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6980 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6981%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6982 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6983%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6984 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6985%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6986 <i>; yields {i32}:result3 = 8</i>
6987%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6988</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6989
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6990</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6991
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6992
6993<!-- ======================================================================= -->
6994<div class="doc_subsection">
6995 <a name="int_memorymarkers">Memory Use Markers</a>
6996</div>
6997
6998<div class="doc_text">
6999
7000<p>This class of intrinsics exists to information about the lifetime of memory
7001 objects and ranges where variables are immutable.</p>
7002
7003</div>
7004
7005<!-- _______________________________________________________________________ -->
7006<div class="doc_subsubsection">
7007 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7008</div>
7009
7010<div class="doc_text">
7011
7012<h5>Syntax:</h5>
7013<pre>
7014 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7015</pre>
7016
7017<h5>Overview:</h5>
7018<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7019 object's lifetime.</p>
7020
7021<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7022<p>The first argument is a constant integer representing the size of the
7023 object, or -1 if it is variable sized. The second argument is a pointer to
7024 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7025
7026<h5>Semantics:</h5>
7027<p>This intrinsic indicates that before this point in the code, the value of the
7028 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]7029 never be used and has an undefined value. A load from the pointer that
7030 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7031 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7032
7033</div>
7034
7035<!-- _______________________________________________________________________ -->
7036<div class="doc_subsubsection">
7037 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7038</div>
7039
7040<div class="doc_text">
7041
7042<h5>Syntax:</h5>
7043<pre>
7044 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7045</pre>
7046
7047<h5>Overview:</h5>
7048<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7049 object's lifetime.</p>
7050
7051<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7052<p>The first argument is a constant integer representing the size of the
7053 object, or -1 if it is variable sized. The second argument is a pointer to
7054 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7055
7056<h5>Semantics:</h5>
7057<p>This intrinsic indicates that after this point in the code, the value of the
7058 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7059 never be used and has an undefined value. Any stores into the memory object
7060 following this intrinsic may be removed as dead.
7061
7062</div>
7063
7064<!-- _______________________________________________________________________ -->
7065<div class="doc_subsubsection">
7066 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7067</div>
7068
7069<div class="doc_text">
7070
7071<h5>Syntax:</h5>
7072<pre>
7073 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7074</pre>
7075
7076<h5>Overview:</h5>
7077<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7078 a memory object will not change.</p>
7079
7080<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7081<p>The first argument is a constant integer representing the size of the
7082 object, or -1 if it is variable sized. The second argument is a pointer to
7083 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7084
7085<h5>Semantics:</h5>
7086<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7087 the return value, the referenced memory location is constant and
7088 unchanging.</p>
7089
7090</div>
7091
7092<!-- _______________________________________________________________________ -->
7093<div class="doc_subsubsection">
7094 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7095</div>
7096
7097<div class="doc_text">
7098
7099<h5>Syntax:</h5>
7100<pre>
7101 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7102</pre>
7103
7104<h5>Overview:</h5>
7105<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7106 a memory object are mutable.</p>
7107
7108<h5>Arguments:</h5>
7109<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7110 The second argument is a constant integer representing the size of the
7111 object, or -1 if it is variable sized and the third argument is a pointer
7112 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7113
7114<h5>Semantics:</h5>
7115<p>This intrinsic indicates that the memory is mutable again.</p>
7116
7117</div>
7118
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7119<!-- ======================================================================= -->
7120<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7121 <a name="int_general">General Intrinsics</a>
7122</div>
7123
7124<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7125
7126<p>This class of intrinsics is designed to be generic and has no specific
7127 purpose.</p>
7128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7129</div>
7130
7131<!-- _______________________________________________________________________ -->
7132<div class="doc_subsubsection">
7133 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7134</div>
7135
7136<div class="doc_text">
7137
7138<h5>Syntax:</h5>
7139<pre>
7140 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7141</pre>
7142
7143<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7144<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7145
7146<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7147<p>The first argument is a pointer to a value, the second is a pointer to a
7148 global string, the third is a pointer to a global string which is the source
7149 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7150
7151<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7152<p>This intrinsic allows annotation of local variables with arbitrary strings.
7153 This can be useful for special purpose optimizations that want to look for
7154 these annotations. These have no other defined use, they are ignored by code
7155 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7157</div>
7158
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7159<!-- _______________________________________________________________________ -->
7160<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7161 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7162</div>
7163
7164<div class="doc_text">
7165
7166<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7167<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7168 any integer bit width.</p>
7169
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7170<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7171 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7172 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7173 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7174 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7175 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]7176</pre>
7177
7178<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7179<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7180
7181<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7182<p>The first argument is an integer value (result of some expression), the
7183 second is a pointer to a global string, the third is a pointer to a global
7184 string which is the source file name, and the last argument is the line
7185 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7186
7187<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7188<p>This intrinsic allows annotations to be put on arbitrary expressions with
7189 arbitrary strings. This can be useful for special purpose optimizations that
7190 want to look for these annotations. These have no other defined use, they
7191 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7192
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7193</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7194
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7195<!-- _______________________________________________________________________ -->
7196<div class="doc_subsubsection">
7197 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7198</div>
7199
7200<div class="doc_text">
7201
7202<h5>Syntax:</h5>
7203<pre>
7204 declare void @llvm.trap()
7205</pre>
7206
7207<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7208<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7209
7210<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7211<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7212
7213<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7214<p>This intrinsics is lowered to the target dependent trap instruction. If the
7215 target does not have a trap instruction, this intrinsic will be lowered to
7216 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7217
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7218</div>
7219
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7220<!-- _______________________________________________________________________ -->
7221<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7222 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7223</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7224
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7225<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7226
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7227<h5>Syntax:</h5>
7228<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7229 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7230</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7231
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7232<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7233<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7234 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7235 ensure that it is placed on the stack before local variables.</p>
7236
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7237<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7238<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7239 arguments. The first argument is the value loaded from the stack
7240 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7241 that has enough space to hold the value of the guard.</p>
7242
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7243<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7244<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7245 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7246 stack. This is to ensure that if a local variable on the stack is
7247 overwritten, it will destroy the value of the guard. When the function exits,
7248 the guard on the stack is checked against the original guard. If they're
7249 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7250 function.</p>
7251
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7252</div>
7253
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7254<!-- _______________________________________________________________________ -->
7255<div class="doc_subsubsection">
7256 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7257</div>
7258
7259<div class="doc_text">
7260
7261<h5>Syntax:</h5>
7262<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7263 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7264 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7265</pre>
7266
7267<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7268<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame^]7269 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7270 operation like memcpy will either overflow a buffer that corresponds to
7271 an object, or b) to determine that a runtime check for overflow isn't
7272 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7273 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7274
7275<h5>Arguments:</h5>
7276<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7277 argument is a pointer to or into the <tt>object</tt>. The second argument
7278 is a boolean 0 or 1. This argument determines whether you want the
7279 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7280 1, variables are not allowed.</p>
7281
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7282<h5>Semantics:</h5>
7283<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7284 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7285 (depending on the <tt>type</tt> argument if the size cannot be determined
7286 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7287
7288</div>
7289
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7290<!-- *********************************************************************** -->
7291<hr>
7292<address>
7293 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7295 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7297
7298 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7299 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7300 Last modified: $Date$
7301</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7303</body>
7304</html>