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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 0101f9df1ab37d7f99cd6ea3c8777946e4c1b2ee / . / 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
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2332<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2333 the program that isn't available in the instructions, or that isn't easily
2334 computable. Similarly, the code generator may expect a certain metadata
2335 format to be used to express debugging information.</p>
2336
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2337</div>
2338
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2339<!-- *********************************************************************** -->
2340<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2341<!-- *********************************************************************** -->
2342
2343<!-- ======================================================================= -->
2344<div class="doc_subsection">
2345<a name="inlineasm">Inline Assembler Expressions</a>
2346</div>
2347
2348<div class="doc_text">
2349
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2350<p>LLVM supports inline assembler expressions (as opposed
2351 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2352 a special value. This value represents the inline assembler as a string
2353 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2354 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2355 expression has side effects, and a flag indicating whether the function
2356 containing the asm needs to align its stack conservatively. An example
2357 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2358
2359<div class="doc_code">
2360<pre>
2361i32 (i32) asm "bswap $0", "=r,r"
2362</pre>
2363</div>
2364
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2365<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2366 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2367 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2368
2369<div class="doc_code">
2370<pre>
2371%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2372</pre>
2373</div>
2374
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2375<p>Inline asms with side effects not visible in the constraint list must be
2376 marked as having side effects. This is done through the use of the
2377 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378
2379<div class="doc_code">
2380<pre>
2381call void asm sideeffect "eieio", ""()
2382</pre>
2383</div>
2384
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2385<p>In some cases inline asms will contain code that will not work unless the
2386 stack is aligned in some way, such as calls or SSE instructions on x86,
2387 yet will not contain code that does that alignment within the asm.
2388 The compiler should make conservative assumptions about what the asm might
2389 contain and should generate its usual stack alignment code in the prologue
2390 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2391
2392<div class="doc_code">
2393<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2394call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2395</pre>
2396</div>
2397
2398<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2399 first.</p>
2400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2401<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2402 documented here. Constraints on what can be done (e.g. duplication, moving,
2403 etc need to be documented). This is probably best done by reference to
2404 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2405
2406</div>
2407
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2408
2409<!-- *********************************************************************** -->
2410<div class="doc_section">
2411 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2412</div>
2413<!-- *********************************************************************** -->
2414
2415<p>LLVM has a number of "magic" global variables that contain data that affect
2416code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2417of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2418section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2419by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2420
2421<!-- ======================================================================= -->
2422<div class="doc_subsection">
2423<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2424</div>
2425
2426<div class="doc_text">
2427
2428<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2429href="#linkage_appending">appending linkage</a>. This array contains a list of
2430pointers to global variables and functions which may optionally have a pointer
2431cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2432
2433<pre>
2434 @X = global i8 4
2435 @Y = global i32 123
2436
2437 @llvm.used = appending global [2 x i8*] [
2438 i8* @X,
2439 i8* bitcast (i32* @Y to i8*)
2440 ], section "llvm.metadata"
2441</pre>
2442
2443<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2444compiler, assembler, and linker are required to treat the symbol as if there is
2445a reference to the global that it cannot see. For example, if a variable has
2446internal linkage and no references other than that from the <tt>@llvm.used</tt>
2447list, it cannot be deleted. This is commonly used to represent references from
2448inline asms and other things the compiler cannot "see", and corresponds to
2449"attribute((used))" in GNU C.</p>
2450
2451<p>On some targets, the code generator must emit a directive to the assembler or
2452object file to prevent the assembler and linker from molesting the symbol.</p>
2453
2454</div>
2455
2456<!-- ======================================================================= -->
2457<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2458<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2459</div>
2460
2461<div class="doc_text">
2462
2463<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2464<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2465touching the symbol. On targets that support it, this allows an intelligent
2466linker to optimize references to the symbol without being impeded as it would be
2467by <tt>@llvm.used</tt>.</p>
2468
2469<p>This is a rare construct that should only be used in rare circumstances, and
2470should not be exposed to source languages.</p>
2471
2472</div>
2473
2474<!-- ======================================================================= -->
2475<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2476<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2477</div>
2478
2479<div class="doc_text">
2480
2481<p>TODO: Describe this.</p>
2482
2483</div>
2484
2485<!-- ======================================================================= -->
2486<div class="doc_subsection">
2487<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2488</div>
2489
2490<div class="doc_text">
2491
2492<p>TODO: Describe this.</p>
2493
2494</div>
2495
2496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2497<!-- *********************************************************************** -->
2498<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2499<!-- *********************************************************************** -->
2500
2501<div class="doc_text">
2502
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2503<p>The LLVM instruction set consists of several different classifications of
2504 instructions: <a href="#terminators">terminator
2505 instructions</a>, <a href="#binaryops">binary instructions</a>,
2506 <a href="#bitwiseops">bitwise binary instructions</a>,
2507 <a href="#memoryops">memory instructions</a>, and
2508 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2509
2510</div>
2511
2512<!-- ======================================================================= -->
2513<div class="doc_subsection"> <a name="terminators">Terminator
2514Instructions</a> </div>
2515
2516<div class="doc_text">
2517
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2518<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2519 in a program ends with a "Terminator" instruction, which indicates which
2520 block should be executed after the current block is finished. These
2521 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2522 control flow, not values (the one exception being the
2523 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2524
2525<p>There are six different terminator instructions: the
2526 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2527 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2528 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2529 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2530 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2531 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2532 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2533
2534</div>
2535
2536<!-- _______________________________________________________________________ -->
2537<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2538Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2539
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2542<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2543<pre>
2544 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]2545 ret void <i>; Return from void function</i>
2546</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2549<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2550 a value) from a function back to the caller.</p>
2551
2552<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2553 value and then causes control flow, and one that just causes control flow to
2554 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2556<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2557<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2558 return value. The type of the return value must be a
2559 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2560
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2561<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2562 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2563 value or a return value with a type that does not match its type, or if it
2564 has a void return type and contains a '<tt>ret</tt>' instruction with a
2565 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2567<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2568<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2569 the calling function's context. If the caller is a
2570 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2571 instruction after the call. If the caller was an
2572 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2573 the beginning of the "normal" destination block. If the instruction returns
2574 a value, that value shall set the call or invoke instruction's return
2575 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2578<pre>
2579 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2581 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]2582</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2584</div>
2585<!-- _______________________________________________________________________ -->
2586<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2588<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2591<pre>
2592 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]2593</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2595<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2596<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2597 different basic block in the current function. There are two forms of this
2598 instruction, corresponding to a conditional branch and an unconditional
2599 branch.</p>
2600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2601<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2602<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2603 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2604 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2605 target.</p>
2606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2607<h5>Semantics:</h5>
2608<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2609 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2610 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2611 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2613<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2614<pre>
2615Test:
2616 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2617 br i1 %cond, label %IfEqual, label %IfUnequal
2618IfEqual:
2619 <a href="#i_ret">ret</a> i32 1
2620IfUnequal:
2621 <a href="#i_ret">ret</a> i32 0
2622</pre>
2623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2626<!-- _______________________________________________________________________ -->
2627<div class="doc_subsubsection">
2628 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2629</div>
2630
2631<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2632
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2633<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634<pre>
2635 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2636</pre>
2637
2638<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2639<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]2640 several different places. It is a generalization of the '<tt>br</tt>'
2641 instruction, allowing a branch to occur to one of many possible
2642 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643
2644<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2646 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2647 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2648 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2649
2650<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2651<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2652 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2653 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2654 transferred to the corresponding destination; otherwise, control flow is
2655 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656
2657<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2658<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2659 <tt>switch</tt> instruction, this instruction may be code generated in
2660 different ways. For example, it could be generated as a series of chained
2661 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662
2663<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2664<pre>
2665 <i>; Emulate a conditional br instruction</i>
2666 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2667 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668
2669 <i>; Emulate an unconditional br instruction</i>
2670 switch i32 0, label %dest [ ]
2671
2672 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2673 switch i32 %val, label %otherwise [ i32 0, label %onzero
2674 i32 1, label %onone
2675 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2676</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2678</div>
2679
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2680
2681<!-- _______________________________________________________________________ -->
2682<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2683 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2684</div>
2685
2686<div class="doc_text">
2687
2688<h5>Syntax:</h5>
2689<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2690 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]2691</pre>
2692
2693<h5>Overview:</h5>
2694
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2695<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2696 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2697 "<tt>address</tt>". Address must be derived from a <a
2698 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2699
2700<h5>Arguments:</h5>
2701
2702<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2703 rest of the arguments indicate the full set of possible destinations that the
2704 address may point to. Blocks are allowed to occur multiple times in the
2705 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2706
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2707<p>This destination list is required so that dataflow analysis has an accurate
2708 understanding of the CFG.</p>
2709
2710<h5>Semantics:</h5>
2711
2712<p>Control transfers to the block specified in the address argument. All
2713 possible destination blocks must be listed in the label list, otherwise this
2714 instruction has undefined behavior. This implies that jumps to labels
2715 defined in other functions have undefined behavior as well.</p>
2716
2717<h5>Implementation:</h5>
2718
2719<p>This is typically implemented with a jump through a register.</p>
2720
2721<h5>Example:</h5>
2722<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2723 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2724</pre>
2725
2726</div>
2727
2728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2729<!-- _______________________________________________________________________ -->
2730<div class="doc_subsubsection">
2731 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2732</div>
2733
2734<div class="doc_text">
2735
2736<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2737<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2738 &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]2739 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2740</pre>
2741
2742<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2743<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2744 function, with the possibility of control flow transfer to either the
2745 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2746 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2747 control flow will return to the "normal" label. If the callee (or any
2748 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2749 instruction, control is interrupted and continued at the dynamically nearest
2750 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2751
2752<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2753<p>This instruction requires several arguments:</p>
2754
2755<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2756 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2757 convention</a> the call should use. If none is specified, the call
2758 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2759
2760 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2761 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2762 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2763
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2764 <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]2765 function value being invoked. In most cases, this is a direct function
2766 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2767 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768
2769 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2770 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2771
2772 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2773 signature argument types. If the function signature indicates the
2774 function accepts a variable number of arguments, the extra arguments can
2775 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2776
2777 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2778 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779
2780 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2781 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2783 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2784 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2785 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2786</ol>
2787
2788<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2789<p>This instruction is designed to operate as a standard
2790 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2791 primary difference is that it establishes an association with a label, which
2792 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793
2794<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2795 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2796 exception. Additionally, this is important for implementation of
2797 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2799<p>For the purposes of the SSA form, the definition of the value returned by the
2800 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2801 block to the "normal" label. If the callee unwinds then no return value is
2802 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<h5>Example:</h5>
2805<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2806 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2808 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809 unwind label %TestCleanup <i>; {i32}:retval set</i>
2810</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2811
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2812</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2813
2814<!-- _______________________________________________________________________ -->
2815
2816<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2817Instruction</a> </div>
2818
2819<div class="doc_text">
2820
2821<h5>Syntax:</h5>
2822<pre>
2823 unwind
2824</pre>
2825
2826<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2827<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2828 at the first callee in the dynamic call stack which used
2829 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2830 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2831
2832<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2833<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2834 immediately halt. The dynamic call stack is then searched for the
2835 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2836 Once found, execution continues at the "exceptional" destination block
2837 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2838 instruction in the dynamic call chain, undefined behavior results.</p>
2839
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2840</div>
2841
2842<!-- _______________________________________________________________________ -->
2843
2844<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2845Instruction</a> </div>
2846
2847<div class="doc_text">
2848
2849<h5>Syntax:</h5>
2850<pre>
2851 unreachable
2852</pre>
2853
2854<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2856 instruction is used to inform the optimizer that a particular portion of the
2857 code is not reachable. This can be used to indicate that the code after a
2858 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2859
2860<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2861<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2863</div>
2864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865<!-- ======================================================================= -->
2866<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2869
2870<p>Binary operators are used to do most of the computation in a program. They
2871 require two operands of the same type, execute an operation on them, and
2872 produce a single value. The operands might represent multiple data, as is
2873 the case with the <a href="#t_vector">vector</a> data type. The result value
2874 has the same type as its operands.</p>
2875
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2876<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2878</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2880<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2881<div class="doc_subsubsection">
2882 <a name="i_add">'<tt>add</tt>' Instruction</a>
2883</div>
2884
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2885<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2887<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2888<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2889 &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]2890 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2891 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2892 &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]2893</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2895<h5>Overview:</h5>
2896<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2899<p>The two arguments to the '<tt>add</tt>' instruction must
2900 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2901 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2903<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2904<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2905
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2906<p>If the sum has unsigned overflow, the result returned is the mathematical
2907 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]2908
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2909<p>Because LLVM integers use a two's complement representation, this instruction
2910 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2911
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2912<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2913 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2914 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2915 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2918<pre>
2919 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2922</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2924<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2925<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2926 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2927</div>
2928
2929<div class="doc_text">
2930
2931<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2932<pre>
2933 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2934</pre>
2935
2936<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2937<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2938
2939<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2940<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2941 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2942 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2943
2944<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2945<p>The value produced is the floating point sum of the two operands.</p>
2946
2947<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2948<pre>
2949 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2950</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2951
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2952</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2953
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
2955<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2956 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2957</div>
2958
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2960
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2961<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2962<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2963 &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]2964 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2965 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2966 &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]2967</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2968
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2969<h5>Overview:</h5>
2970<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2971 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2972
2973<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2974 '<tt>neg</tt>' instruction present in most other intermediate
2975 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2977<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2978<p>The two arguments to the '<tt>sub</tt>' instruction must
2979 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2980 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2981
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2982<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2983<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2984
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2985<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2986 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
2987 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2988
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2989<p>Because LLVM integers use a two's complement representation, this instruction
2990 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2991
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2992<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2993 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2994 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
2995 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2997<h5>Example:</h5>
2998<pre>
2999 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3000 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3001</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3002
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3003</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3005<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3006<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3007 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3008</div>
3009
3010<div class="doc_text">
3011
3012<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3013<pre>
3014 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3015</pre>
3016
3017<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3018<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3019 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3020
3021<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3022 '<tt>fneg</tt>' instruction present in most other intermediate
3023 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3024
3025<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3026<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3027 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3028 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3029
3030<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3031<p>The value produced is the floating point difference of the two operands.</p>
3032
3033<h5>Example:</h5>
3034<pre>
3035 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3036 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3037</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3038
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3039</div>
3040
3041<!-- _______________________________________________________________________ -->
3042<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3043 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3044</div>
3045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3046<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3048<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3049<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3050 &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]3051 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3052 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3053 &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]3054</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3055
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3056<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3057<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3058
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3059<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3060<p>The two arguments to the '<tt>mul</tt>' instruction must
3061 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3062 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3063
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3064<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3065<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3066
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3067<p>If the result of the multiplication has unsigned overflow, the result
3068 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3069 width of the result.</p>
3070
3071<p>Because LLVM integers use a two's complement representation, and the result
3072 is the same width as the operands, this instruction returns the correct
3073 result for both signed and unsigned integers. If a full product
3074 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3075 be sign-extended or zero-extended as appropriate to the width of the full
3076 product.</p>
3077
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3078<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3079 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3080 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3081 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3082
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3083<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3084<pre>
3085 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3086</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3087
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3088</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3090<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3091<div class="doc_subsubsection">
3092 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3093</div>
3094
3095<div class="doc_text">
3096
3097<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3098<pre>
3099 &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]3100</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3101
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3102<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3103<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3104
3105<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3106<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3107 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3108 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3109
3110<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3111<p>The value produced is the floating point product of the two operands.</p>
3112
3113<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3114<pre>
3115 &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]3116</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3117
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3118</div>
3119
3120<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3121<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3122</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3123
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3124<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3126<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3127<pre>
3128 &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]3129</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3130
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3131<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3132<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3134<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3135<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3136 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3137 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3138
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3139<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3140<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3141
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3142<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3143 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3144
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3145<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3146
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3147<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3148<pre>
3149 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3150</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3151
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3152</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3154<!-- _______________________________________________________________________ -->
3155<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3156</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3158<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3160<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3161<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3162 &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]3163 &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]3164</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3165
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3166<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3167<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3169<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3170<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3171 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3172 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175<p>The value produced is the signed integer quotient of the two operands rounded
3176 towards zero.</p>
3177
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3178<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3179 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3180
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3181<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3182 undefined behavior; this is a rare case, but can occur, for example, by doing
3183 a 32-bit division of -2147483648 by -1.</p>
3184
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3185<p>If the <tt>exact</tt> keyword is present, the result value of the
3186 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3187 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3190<pre>
3191 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3192</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3194</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3195
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3196<!-- _______________________________________________________________________ -->
3197<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3198Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3200<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3202<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3203<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3204 &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]3205</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3206
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3207<h5>Overview:</h5>
3208<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3210<h5>Arguments:</h5>
3211<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3212 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3213 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3215<h5>Semantics:</h5>
3216<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3218<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3219<pre>
3220 &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]3221</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3224
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3225<!-- _______________________________________________________________________ -->
3226<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3227</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3229<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3231<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3232<pre>
3233 &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]3234</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3236<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3237<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3238 division of its two arguments.</p>
3239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3240<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3241<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3242 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3243 values. Both arguments must have identical types.</p>
3244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3245<h5>Semantics:</h5>
3246<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3247 This instruction always performs an unsigned division to get the
3248 remainder.</p>
3249
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3250<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3251 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3252
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3253<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3256<pre>
3257 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3258</pre>
3259
3260</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3262<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3263<div class="doc_subsubsection">
3264 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3265</div>
3266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3267<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3268
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3269<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3270<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3271 &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]3272</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3274<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3275<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3276 division of its two operands. This instruction can also take
3277 <a href="#t_vector">vector</a> versions of the values in which case the
3278 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3280<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3281<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3282 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3283 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3285<h5>Semantics:</h5>
3286<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3287 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3288 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3289 a value. For more information about the difference,
3290 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3291 Math Forum</a>. For a table of how this is implemented in various languages,
3292 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3293 Wikipedia: modulo operation</a>.</p>
3294
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3295<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3296 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3297
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3298<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3299 Overflow also leads to undefined behavior; this is a rare case, but can
3300 occur, for example, by taking the remainder of a 32-bit division of
3301 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3302 lets srem be implemented using instructions that return both the result of
3303 the division and the remainder.)</p>
3304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3305<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3306<pre>
3307 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3308</pre>
3309
3310</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3311
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3312<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3313<div class="doc_subsubsection">
3314 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3316<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3318<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3319<pre>
3320 &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]3321</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3322
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3323<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3324<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3325 its two operands.</p>
3326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327<h5>Arguments:</h5>
3328<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3329 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3330 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3332<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3333<p>This instruction returns the <i>remainder</i> of a division. The remainder
3334 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3336<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3337<pre>
3338 &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]3339</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341</div>
3342
3343<!-- ======================================================================= -->
3344<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3345Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3346
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3347<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3348
3349<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3350 program. They are generally very efficient instructions and can commonly be
3351 strength reduced from other instructions. They require two operands of the
3352 same type, execute an operation on them, and produce a single value. The
3353 resulting value is the same type as its operands.</p>
3354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3355</div>
3356
3357<!-- _______________________________________________________________________ -->
3358<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
3359Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3362
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3363<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3364<pre>
3365 &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]3366</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3368<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3369<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3370 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3372<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3373<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3374 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3375 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3376
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3377<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3378<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3379 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3380 is (statically or dynamically) negative or equal to or larger than the number
3381 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3382 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3383 shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3384
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3385<h5>Example:</h5>
3386<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3387 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3388 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3389 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3390 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3391 &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]3392</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3393
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3394</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3396<!-- _______________________________________________________________________ -->
3397<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3398Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3400<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3402<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3403<pre>
3404 &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]3405</pre>
3406
3407<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3408<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3409 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3410
3411<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3412<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3413 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3414 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3415
3416<h5>Semantics:</h5>
3417<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3418 significant bits of the result will be filled with zero bits after the shift.
3419 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3420 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3421 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3422 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3423
3424<h5>Example:</h5>
3425<pre>
3426 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3427 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3428 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3429 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3430 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3431 &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]3432</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3433
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3434</div>
3435
3436<!-- _______________________________________________________________________ -->
3437<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3438Instruction</a> </div>
3439<div class="doc_text">
3440
3441<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3442<pre>
3443 &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]3444</pre>
3445
3446<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3447<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3448 operand shifted to the right a specified number of bits with sign
3449 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450
3451<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3452<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3453 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3454 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3455
3456<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3457<p>This instruction always performs an arithmetic shift right operation, The
3458 most significant bits of the result will be filled with the sign bit
3459 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3460 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3461 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3462 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3463
3464<h5>Example:</h5>
3465<pre>
3466 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3467 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3468 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3469 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3470 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3471 &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]3472</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3474</div>
3475
3476<!-- _______________________________________________________________________ -->
3477<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3478Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3480<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3482<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3483<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3484 &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]3485</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3487<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3488<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3489 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3491<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3492<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3493 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3494 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3496<h5>Semantics:</h5>
3497<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3499<table border="1" cellspacing="0" cellpadding="4">
3500 <tbody>
3501 <tr>
3502 <td>In0</td>
3503 <td>In1</td>
3504 <td>Out</td>
3505 </tr>
3506 <tr>
3507 <td>0</td>
3508 <td>0</td>
3509 <td>0</td>
3510 </tr>
3511 <tr>
3512 <td>0</td>
3513 <td>1</td>
3514 <td>0</td>
3515 </tr>
3516 <tr>
3517 <td>1</td>
3518 <td>0</td>
3519 <td>0</td>
3520 </tr>
3521 <tr>
3522 <td>1</td>
3523 <td>1</td>
3524 <td>1</td>
3525 </tr>
3526 </tbody>
3527</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3529<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3530<pre>
3531 &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]3532 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3533 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3534</pre>
3535</div>
3536<!-- _______________________________________________________________________ -->
3537<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3538
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3539<div class="doc_text">
3540
3541<h5>Syntax:</h5>
3542<pre>
3543 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3544</pre>
3545
3546<h5>Overview:</h5>
3547<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3548 two operands.</p>
3549
3550<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3551<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3552 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3553 values. Both arguments must have identical types.</p>
3554
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3555<h5>Semantics:</h5>
3556<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3557
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3558<table border="1" cellspacing="0" cellpadding="4">
3559 <tbody>
3560 <tr>
3561 <td>In0</td>
3562 <td>In1</td>
3563 <td>Out</td>
3564 </tr>
3565 <tr>
3566 <td>0</td>
3567 <td>0</td>
3568 <td>0</td>
3569 </tr>
3570 <tr>
3571 <td>0</td>
3572 <td>1</td>
3573 <td>1</td>
3574 </tr>
3575 <tr>
3576 <td>1</td>
3577 <td>0</td>
3578 <td>1</td>
3579 </tr>
3580 <tr>
3581 <td>1</td>
3582 <td>1</td>
3583 <td>1</td>
3584 </tr>
3585 </tbody>
3586</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3588<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3589<pre>
3590 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3591 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3592 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3593</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3595</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3597<!-- _______________________________________________________________________ -->
3598<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3599Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3601<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3603<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3604<pre>
3605 &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]3606</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3608<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3609<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3610 its two operands. The <tt>xor</tt> is used to implement the "one's
3611 complement" operation, which is the "~" operator in C.</p>
3612
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3613<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3614<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3615 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3616 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618<h5>Semantics:</h5>
3619<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3621<table border="1" cellspacing="0" cellpadding="4">
3622 <tbody>
3623 <tr>
3624 <td>In0</td>
3625 <td>In1</td>
3626 <td>Out</td>
3627 </tr>
3628 <tr>
3629 <td>0</td>
3630 <td>0</td>
3631 <td>0</td>
3632 </tr>
3633 <tr>
3634 <td>0</td>
3635 <td>1</td>
3636 <td>1</td>
3637 </tr>
3638 <tr>
3639 <td>1</td>
3640 <td>0</td>
3641 <td>1</td>
3642 </tr>
3643 <tr>
3644 <td>1</td>
3645 <td>1</td>
3646 <td>0</td>
3647 </tr>
3648 </tbody>
3649</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3650
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3651<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3652<pre>
3653 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3654 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3655 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3656 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3657</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3659</div>
3660
3661<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3662<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3663 <a name="vectorops">Vector Operations</a>
3664</div>
3665
3666<div class="doc_text">
3667
3668<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3669 target-independent manner. These instructions cover the element-access and
3670 vector-specific operations needed to process vectors effectively. While LLVM
3671 does directly support these vector operations, many sophisticated algorithms
3672 will want to use target-specific intrinsics to take full advantage of a
3673 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3674
3675</div>
3676
3677<!-- _______________________________________________________________________ -->
3678<div class="doc_subsubsection">
3679 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3680</div>
3681
3682<div class="doc_text">
3683
3684<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3685<pre>
3686 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3687</pre>
3688
3689<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3690<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3691 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3692
3693
3694<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3695<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3696 of <a href="#t_vector">vector</a> type. The second operand is an index
3697 indicating the position from which to extract the element. The index may be
3698 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3699
3700<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3701<p>The result is a scalar of the same type as the element type of
3702 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3703 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3704 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705
3706<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3707<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3708 &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]3709</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3711</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712
3713<!-- _______________________________________________________________________ -->
3714<div class="doc_subsubsection">
3715 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3716</div>
3717
3718<div class="doc_text">
3719
3720<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3721<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3722 &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]3723</pre>
3724
3725<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3726<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3727 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3728
3729<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3730<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3731 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3732 whose type must equal the element type of the first operand. The third
3733 operand is an index indicating the position at which to insert the value.
3734 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735
3736<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3737<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3738 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3739 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3740 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3741
3742<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3743<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3744 &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]3745</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3747</div>
3748
3749<!-- _______________________________________________________________________ -->
3750<div class="doc_subsubsection">
3751 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3752</div>
3753
3754<div class="doc_text">
3755
3756<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3757<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3758 &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]3759</pre>
3760
3761<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3762<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3763 from two input vectors, returning a vector with the same element type as the
3764 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3765
3766<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3767<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3768 with types that match each other. The third argument is a shuffle mask whose
3769 element type is always 'i32'. The result of the instruction is a vector
3770 whose length is the same as the shuffle mask and whose element type is the
3771 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3772
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3773<p>The shuffle mask operand is required to be a constant vector with either
3774 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3775
3776<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3777<p>The elements of the two input vectors are numbered from left to right across
3778 both of the vectors. The shuffle mask operand specifies, for each element of
3779 the result vector, which element of the two input vectors the result element
3780 gets. The element selector may be undef (meaning "don't care") and the
3781 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3782
3783<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3784<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3785 &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]3786 &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]3787 &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]3788 &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]3789 &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]3790 &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]3791 &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]3792 &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]3793</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3794
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3795</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3796
3797<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3798<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3799 <a name="aggregateops">Aggregate Operations</a>
3800</div>
3801
3802<div class="doc_text">
3803
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3804<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3805
3806</div>
3807
3808<!-- _______________________________________________________________________ -->
3809<div class="doc_subsubsection">
3810 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3811</div>
3812
3813<div class="doc_text">
3814
3815<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3816<pre>
3817 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3818</pre>
3819
3820<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3821<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3822 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3823
3824<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3825<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3826 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3827 operands are constant indices to specify which value to extract in a similar
3828 manner as indices in a
3829 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3830
3831<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3832<p>The result is the value at the position in the aggregate specified by the
3833 index operands.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3834
3835<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3836<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3837 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3838</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3839
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3840</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3841
3842<!-- _______________________________________________________________________ -->
3843<div class="doc_subsubsection">
3844 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3845</div>
3846
3847<div class="doc_text">
3848
3849<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3850<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3851 &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]3852</pre>
3853
3854<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3855<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3856 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3857
3858
3859<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3860<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3861 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3862 second operand is a first-class value to insert. The following operands are
3863 constant indices indicating the position at which to insert the value in a
3864 similar manner as indices in a
3865 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3866 value to insert must have the same type as the value identified by the
3867 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3868
3869<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3870<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3871 that of <tt>val</tt> except that the value at the position specified by the
3872 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3873
3874<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3875<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3876 &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]3877</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3878
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3879</div>
3880
3881
3882<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3883<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3884 <a name="memoryops">Memory Access and Addressing Operations</a>
3885</div>
3886
3887<div class="doc_text">
3888
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3889<p>A key design point of an SSA-based representation is how it represents
3890 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3891 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3892 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3893
3894</div>
3895
3896<!-- _______________________________________________________________________ -->
3897<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3899</div>
3900
3901<div class="doc_text">
3902
3903<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3904<pre>
3905 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3906</pre>
3907
3908<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3910 currently executing function, to be automatically released when this function
3911 returns to its caller. The object is always allocated in the generic address
3912 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3913
3914<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3915<p>The '<tt>alloca</tt>' instruction
3916 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3917 runtime stack, returning a pointer of the appropriate type to the program.
3918 If "NumElements" is specified, it is the number of elements allocated,
3919 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3920 specified, the value result of the allocation is guaranteed to be aligned to
3921 at least that boundary. If not specified, or if zero, the target can choose
3922 to align the allocation on any convenient boundary compatible with the
3923 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3924
3925<p>'<tt>type</tt>' may be any sized type.</p>
3926
3927<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3928<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3929 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3930 memory is automatically released when the function returns. The
3931 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3932 variables that must have an address available. When the function returns
3933 (either with the <tt><a href="#i_ret">ret</a></tt>
3934 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3935 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3936
3937<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3939 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3940 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3941 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3942 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3943</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3945</div>
3946
3947<!-- _______________________________________________________________________ -->
3948<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3949Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3950
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3951<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3952
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3953<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3954<pre>
3955 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3956 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3957</pre>
3958
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3959<h5>Overview:</h5>
3960<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3962<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3963<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
3964 from which to load. The pointer must point to
3965 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3966 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
3967 number or order of execution of this <tt>load</tt> with other
3968 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3969 instructions. </p>
3970
3971<p>The optional constant "align" argument specifies the alignment of the
3972 operation (that is, the alignment of the memory address). A value of 0 or an
3973 omitted "align" argument means that the operation has the preferential
3974 alignment for the target. It is the responsibility of the code emitter to
3975 ensure that the alignment information is correct. Overestimating the
3976 alignment results in an undefined behavior. Underestimating the alignment may
3977 produce less efficient code. An alignment of 1 is always safe.</p>
3978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3980<p>The location of memory pointed to is loaded. If the value being loaded is of
3981 scalar type then the number of bytes read does not exceed the minimum number
3982 of bytes needed to hold all bits of the type. For example, loading an
3983 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
3984 <tt>i20</tt> with a size that is not an integral number of bytes, the result
3985 is undefined if the value was not originally written using a store of the
3986 same type.</p>
3987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3988<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3989<pre>
3990 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3991 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3992 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3993</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3994
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3995</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3996
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3997<!-- _______________________________________________________________________ -->
3998<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3999Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4000
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4001<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4002
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4003<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4004<pre>
4005 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]4006 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4007</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4008
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4009<h5>Overview:</h5>
4010<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4011
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4012<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4013<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4014 and an address at which to store it. The type of the
4015 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4016 the <a href="#t_firstclass">first class</a> type of the
4017 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4018 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4019 or order of execution of this <tt>store</tt> with other
4020 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4021 instructions.</p>
4022
4023<p>The optional constant "align" argument specifies the alignment of the
4024 operation (that is, the alignment of the memory address). A value of 0 or an
4025 omitted "align" argument means that the operation has the preferential
4026 alignment for the target. It is the responsibility of the code emitter to
4027 ensure that the alignment information is correct. Overestimating the
4028 alignment results in an undefined behavior. Underestimating the alignment may
4029 produce less efficient code. An alignment of 1 is always safe.</p>
4030
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4031<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4032<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4033 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4034 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4035 does not exceed the minimum number of bytes needed to hold all bits of the
4036 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4037 writing a value of a type like <tt>i20</tt> with a size that is not an
4038 integral number of bytes, it is unspecified what happens to the extra bits
4039 that do not belong to the type, but they will typically be overwritten.</p>
4040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4042<pre>
4043 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4044 store i32 3, i32* %ptr <i>; yields {void}</i>
4045 %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]4046</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4047
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4048</div>
4049
4050<!-- _______________________________________________________________________ -->
4051<div class="doc_subsubsection">
4052 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4053</div>
4054
4055<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4056
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057<h5>Syntax:</h5>
4058<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4059 &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]4060 &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]4061</pre>
4062
4063<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4064<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4065 subelement of an aggregate data structure. It performs address calculation
4066 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4067
4068<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4069<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4070 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4071 elements of the aggregate object are indexed. The interpretation of each
4072 index is dependent on the type being indexed into. The first index always
4073 indexes the pointer value given as the first argument, the second index
4074 indexes a value of the type pointed to (not necessarily the value directly
4075 pointed to, since the first index can be non-zero), etc. The first type
4076 indexed into must be a pointer value, subsequent types can be arrays, vectors
4077 and structs. Note that subsequent types being indexed into can never be
4078 pointers, since that would require loading the pointer before continuing
4079 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4080
4081<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]4082 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4083 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4084 vector, integers of any width are allowed, and they are not required to be
4085 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4086
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4087<p>For example, let's consider a C code fragment and how it gets compiled to
4088 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4089
4090<div class="doc_code">
4091<pre>
4092struct RT {
4093 char A;
4094 int B[10][20];
4095 char C;
4096};
4097struct ST {
4098 int X;
4099 double Y;
4100 struct RT Z;
4101};
4102
4103int *foo(struct ST *s) {
4104 return &amp;s[1].Z.B[5][13];
4105}
4106</pre>
4107</div>
4108
4109<p>The LLVM code generated by the GCC frontend is:</p>
4110
4111<div class="doc_code">
4112<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4113%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4114%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4115
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4116define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4117entry:
4118 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4119 ret i32* %reg
4120}
4121</pre>
4122</div>
4123
4124<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4125<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]4126 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4127 }</tt>' type, a structure. The second index indexes into the third element
4128 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4129 i8 }</tt>' type, another structure. The third index indexes into the second
4130 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4131 array. The two dimensions of the array are subscripted into, yielding an
4132 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4133 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4134
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4135<p>Note that it is perfectly legal to index partially through a structure,
4136 returning a pointer to an inner element. Because of this, the LLVM code for
4137 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4138
4139<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4140 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4142 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4143 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4144 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4145 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4146 ret i32* %t5
4147 }
4148</pre>
4149
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4150<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4151 <tt>getelementptr</tt> is undefined if the base pointer is not an
4152 <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]4153 that would be formed by successive addition of the offsets implied by the
4154 indices to the base address with infinitely precise arithmetic are not an
4155 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4156 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4157 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4158
4159<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4160 the base address with silently-wrapping two's complement arithmetic, and
4161 the result value of the <tt>getelementptr</tt> may be outside the object
4162 pointed to by the base pointer. The result value may not necessarily be
4163 used to access memory though, even if it happens to point into allocated
4164 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4165 section for more information.</p>
4166
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4167<p>The getelementptr instruction is often confusing. For some more insight into
4168 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4169
4170<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4171<pre>
4172 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4173 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4174 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4175 %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]4176 <i>; yields i8*:eptr</i>
4177 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4178 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4179 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4180</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4182</div>
4183
4184<!-- ======================================================================= -->
4185<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4186</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4188<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4190<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4191 which all take a single operand and a type. They perform various bit
4192 conversions on the operand.</p>
4193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4194</div>
4195
4196<!-- _______________________________________________________________________ -->
4197<div class="doc_subsubsection">
4198 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4199</div>
4200<div class="doc_text">
4201
4202<h5>Syntax:</h5>
4203<pre>
4204 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4205</pre>
4206
4207<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4208<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4209 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210
4211<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4212<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4213 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4214 size and type of the result, which must be
4215 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4216 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4217 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4218
4219<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4220<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4221 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4222 source size must be larger than the destination size, <tt>trunc</tt> cannot
4223 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4224
4225<h5>Example:</h5>
4226<pre>
4227 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4228 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4229 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4230</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4232</div>
4233
4234<!-- _______________________________________________________________________ -->
4235<div class="doc_subsubsection">
4236 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4237</div>
4238<div class="doc_text">
4239
4240<h5>Syntax:</h5>
4241<pre>
4242 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4243</pre>
4244
4245<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4246<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4247 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4248
4249
4250<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4251<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]4252 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4253 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]4254 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4255 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4256
4257<h5>Semantics:</h5>
4258<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]4259 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260
4261<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4262
4263<h5>Example:</h5>
4264<pre>
4265 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4266 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4267</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4268
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4269</div>
4270
4271<!-- _______________________________________________________________________ -->
4272<div class="doc_subsubsection">
4273 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4274</div>
4275<div class="doc_text">
4276
4277<h5>Syntax:</h5>
4278<pre>
4279 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4280</pre>
4281
4282<h5>Overview:</h5>
4283<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4284
4285<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4286<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]4287 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4288 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]4289 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4290 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4291
4292<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4293<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4294 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4295 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4296
4297<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4298
4299<h5>Example:</h5>
4300<pre>
4301 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4302 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4303</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4305</div>
4306
4307<!-- _______________________________________________________________________ -->
4308<div class="doc_subsubsection">
4309 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4310</div>
4311
4312<div class="doc_text">
4313
4314<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315<pre>
4316 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4317</pre>
4318
4319<h5>Overview:</h5>
4320<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4321 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322
4323<h5>Arguments:</h5>
4324<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4325 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4326 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]4327 <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]4328 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4329
4330<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4331<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4332 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4333 <a href="#t_floating">floating point</a> type. If the value cannot fit
4334 within the destination type, <tt>ty2</tt>, then the results are
4335 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4336
4337<h5>Example:</h5>
4338<pre>
4339 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4340 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4341</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4343</div>
4344
4345<!-- _______________________________________________________________________ -->
4346<div class="doc_subsubsection">
4347 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4348</div>
4349<div class="doc_text">
4350
4351<h5>Syntax:</h5>
4352<pre>
4353 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4354</pre>
4355
4356<h5>Overview:</h5>
4357<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]4358 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359
4360<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4361<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4362 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4363 a <a href="#t_floating">floating point</a> type to cast it to. The source
4364 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4365
4366<h5>Semantics:</h5>
4367<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4368 <a href="#t_floating">floating point</a> type to a larger
4369 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4370 used to make a <i>no-op cast</i> because it always changes bits. Use
4371 <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]4372
4373<h5>Example:</h5>
4374<pre>
4375 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4376 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4377</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4379</div>
4380
4381<!-- _______________________________________________________________________ -->
4382<div class="doc_subsubsection">
4383 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4384</div>
4385<div class="doc_text">
4386
4387<h5>Syntax:</h5>
4388<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4389 &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]4390</pre>
4391
4392<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4393<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4394 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4395
4396<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4397<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4398 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4399 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4400 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4401 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4402
4403<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4404<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4405 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4406 towards zero) unsigned integer value. If the value cannot fit
4407 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4409<h5>Example:</h5>
4410<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4411 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4412 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4413 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4414</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4416</div>
4417
4418<!-- _______________________________________________________________________ -->
4419<div class="doc_subsubsection">
4420 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4421</div>
4422<div class="doc_text">
4423
4424<h5>Syntax:</h5>
4425<pre>
4426 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4427</pre>
4428
4429<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4430<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4431 <a href="#t_floating">floating point</a> <tt>value</tt> to
4432 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4433
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4434<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4435<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4436 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4437 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4438 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4439 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4440
4441<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4442<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4443 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4444 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4445 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4447<h5>Example:</h5>
4448<pre>
4449 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4450 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4451 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4452</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4453
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454</div>
4455
4456<!-- _______________________________________________________________________ -->
4457<div class="doc_subsubsection">
4458 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4459</div>
4460<div class="doc_text">
4461
4462<h5>Syntax:</h5>
4463<pre>
4464 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4465</pre>
4466
4467<h5>Overview:</h5>
4468<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4469 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4471<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4472<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]4473 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4474 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4475 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4476 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477
4478<h5>Semantics:</h5>
4479<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4480 integer quantity and converts it to the corresponding floating point
4481 value. If the value cannot fit in the floating point value, the results are
4482 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484<h5>Example:</h5>
4485<pre>
4486 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4487 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4488</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490</div>
4491
4492<!-- _______________________________________________________________________ -->
4493<div class="doc_subsubsection">
4494 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4495</div>
4496<div class="doc_text">
4497
4498<h5>Syntax:</h5>
4499<pre>
4500 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4501</pre>
4502
4503<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4504<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4505 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4506
4507<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4508<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]4509 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4510 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4511 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4512 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4513
4514<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4515<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4516 quantity and converts it to the corresponding floating point value. If the
4517 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4518
4519<h5>Example:</h5>
4520<pre>
4521 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4522 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4523</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4525</div>
4526
4527<!-- _______________________________________________________________________ -->
4528<div class="doc_subsubsection">
4529 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4530</div>
4531<div class="doc_text">
4532
4533<h5>Syntax:</h5>
4534<pre>
4535 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4536</pre>
4537
4538<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4539<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4540 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4541
4542<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4543<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4544 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4545 <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]4546
4547<h5>Semantics:</h5>
4548<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4549 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4550 truncating or zero extending that value to the size of the integer type. If
4551 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4552 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4553 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4554 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4555
4556<h5>Example:</h5>
4557<pre>
4558 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4559 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4560</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4562</div>
4563
4564<!-- _______________________________________________________________________ -->
4565<div class="doc_subsubsection">
4566 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4567</div>
4568<div class="doc_text">
4569
4570<h5>Syntax:</h5>
4571<pre>
4572 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4573</pre>
4574
4575<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4576<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4577 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4578
4579<h5>Arguments:</h5>
4580<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4581 value to cast, and a type to cast it to, which must be a
4582 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4583
4584<h5>Semantics:</h5>
4585<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4586 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4587 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4588 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4589 than the size of a pointer then a zero extension is done. If they are the
4590 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4591
4592<h5>Example:</h5>
4593<pre>
4594 %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]4595 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4596 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4597</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4598
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4599</div>
4600
4601<!-- _______________________________________________________________________ -->
4602<div class="doc_subsubsection">
4603 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4604</div>
4605<div class="doc_text">
4606
4607<h5>Syntax:</h5>
4608<pre>
4609 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4610</pre>
4611
4612<h5>Overview:</h5>
4613<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4614 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4615
4616<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4617<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4618 non-aggregate first class value, and a type to cast it to, which must also be
4619 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4620 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4621 identical. If the source type is a pointer, the destination type must also be
4622 a pointer. This instruction supports bitwise conversion of vectors to
4623 integers and to vectors of other types (as long as they have the same
4624 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4625
4626<h5>Semantics:</h5>
4627<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4628 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4629 this conversion. The conversion is done as if the <tt>value</tt> had been
4630 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4631 be converted to other pointer types with this instruction. To convert
4632 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4633 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4634
4635<h5>Example:</h5>
4636<pre>
4637 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4638 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4639 %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]4640</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4641
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4642</div>
4643
4644<!-- ======================================================================= -->
4645<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4647<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4648
4649<p>The instructions in this category are the "miscellaneous" instructions, which
4650 defy better classification.</p>
4651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4652</div>
4653
4654<!-- _______________________________________________________________________ -->
4655<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4656</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4658<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4660<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4661<pre>
4662 &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]4663</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4665<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4666<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4667 boolean values based on comparison of its two integer, integer vector, or
4668 pointer operands.</p>
4669
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4670<h5>Arguments:</h5>
4671<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4672 the condition code indicating the kind of comparison to perform. It is not a
4673 value, just a keyword. The possible condition code are:</p>
4674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4675<ol>
4676 <li><tt>eq</tt>: equal</li>
4677 <li><tt>ne</tt>: not equal </li>
4678 <li><tt>ugt</tt>: unsigned greater than</li>
4679 <li><tt>uge</tt>: unsigned greater or equal</li>
4680 <li><tt>ult</tt>: unsigned less than</li>
4681 <li><tt>ule</tt>: unsigned less or equal</li>
4682 <li><tt>sgt</tt>: signed greater than</li>
4683 <li><tt>sge</tt>: signed greater or equal</li>
4684 <li><tt>slt</tt>: signed less than</li>
4685 <li><tt>sle</tt>: signed less or equal</li>
4686</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4688<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4689 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4690 typed. They must also be identical types.</p>
4691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4692<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4693<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4694 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4695 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]4696 result, as follows:</p>
4697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4698<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4699 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4700 <tt>false</tt> otherwise. No sign interpretation is necessary or
4701 performed.</li>
4702
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4703 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4704 <tt>false</tt> otherwise. No sign interpretation is necessary or
4705 performed.</li>
4706
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4707 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4708 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4710 <li><tt>uge</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 or equal
4712 to <tt>op2</tt>.</li>
4713
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4714 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4715 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4717 <li><tt>ule</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 or equal to <tt>op2</tt>.</li>
4719
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4721 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723 <li><tt>sge</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 or equal
4725 to <tt>op2</tt>.</li>
4726
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4727 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4728 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4729
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4730 <li><tt>sle</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 or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4734<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4735 values are compared as if they were integers.</p>
4736
4737<p>If the operands are integer vectors, then they are compared element by
4738 element. The result is an <tt>i1</tt> vector with the same number of elements
4739 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4740
4741<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4742<pre>
4743 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4744 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4745 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4746 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4747 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4748 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4749</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4750
4751<p>Note that the code generator does not yet support vector types with
4752 the <tt>icmp</tt> instruction.</p>
4753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4754</div>
4755
4756<!-- _______________________________________________________________________ -->
4757<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4758</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4760<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4762<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4763<pre>
4764 &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]4765</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4767<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4768<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4769 values based on comparison of its operands.</p>
4770
4771<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]4772(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4773
4774<p>If the operands are floating point vectors, then the result type is a vector
4775 of boolean with the same number of elements as the operands being
4776 compared.</p>
4777
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4778<h5>Arguments:</h5>
4779<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4780 the condition code indicating the kind of comparison to perform. It is not a
4781 value, just a keyword. The possible condition code are:</p>
4782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4783<ol>
4784 <li><tt>false</tt>: no comparison, always returns false</li>
4785 <li><tt>oeq</tt>: ordered and equal</li>
4786 <li><tt>ogt</tt>: ordered and greater than </li>
4787 <li><tt>oge</tt>: ordered and greater than or equal</li>
4788 <li><tt>olt</tt>: ordered and less than </li>
4789 <li><tt>ole</tt>: ordered and less than or equal</li>
4790 <li><tt>one</tt>: ordered and not equal</li>
4791 <li><tt>ord</tt>: ordered (no nans)</li>
4792 <li><tt>ueq</tt>: unordered or equal</li>
4793 <li><tt>ugt</tt>: unordered or greater than </li>
4794 <li><tt>uge</tt>: unordered or greater than or equal</li>
4795 <li><tt>ult</tt>: unordered or less than </li>
4796 <li><tt>ule</tt>: unordered or less than or equal</li>
4797 <li><tt>une</tt>: unordered or not equal</li>
4798 <li><tt>uno</tt>: unordered (either nans)</li>
4799 <li><tt>true</tt>: no comparison, always returns true</li>
4800</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4803 <i>unordered</i> means that either operand may be a QNAN.</p>
4804
4805<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4806 a <a href="#t_floating">floating point</a> type or
4807 a <a href="#t_vector">vector</a> of floating point type. They must have
4808 identical types.</p>
4809
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4810<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4811<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4812 according to the condition code given as <tt>cond</tt>. If the operands are
4813 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4814 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4815 follows:</p>
4816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4817<ol>
4818 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4819
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4820 <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]4821 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4823 <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]4824 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4825
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4826 <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]4827 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4828
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4829 <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]4830 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4831
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4832 <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]4833 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4834
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4835 <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]4836 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4838 <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]4839
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4840 <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]4841 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4842
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4843 <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]4844 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4845
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4846 <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]4847 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4848
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4849 <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]4850 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4851
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4852 <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]4853 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4854
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4855 <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]4856 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4857
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4858 <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]4859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4860 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4861</ol>
4862
4863<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4864<pre>
4865 &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]4866 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4867 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4868 &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]4869</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4870
4871<p>Note that the code generator does not yet support vector types with
4872 the <tt>fcmp</tt> instruction.</p>
4873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4874</div>
4875
4876<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4877<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4878 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4879</div>
4880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4881<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4883<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4884<pre>
4885 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4886</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4887
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4888<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4889<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4890 SSA graph representing the function.</p>
4891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4892<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4893<p>The type of the incoming values is specified with the first type field. After
4894 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4895 one pair for each predecessor basic block of the current block. Only values
4896 of <a href="#t_firstclass">first class</a> type may be used as the value
4897 arguments to the PHI node. Only labels may be used as the label
4898 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4899
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4900<p>There must be no non-phi instructions between the start of a basic block and
4901 the PHI instructions: i.e. PHI instructions must be first in a basic
4902 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4903
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4904<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4905 occur on the edge from the corresponding predecessor block to the current
4906 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4907 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4909<h5>Semantics:</h5>
4910<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4911 specified by the pair corresponding to the predecessor basic block that
4912 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4914<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4915<pre>
4916Loop: ; Infinite loop that counts from 0 on up...
4917 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4918 %nextindvar = add i32 %indvar, 1
4919 br label %Loop
4920</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4921
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4922</div>
4923
4924<!-- _______________________________________________________________________ -->
4925<div class="doc_subsubsection">
4926 <a name="i_select">'<tt>select</tt>' Instruction</a>
4927</div>
4928
4929<div class="doc_text">
4930
4931<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4932<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4933 &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>
4934
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4935 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4936</pre>
4937
4938<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4939<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4940 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4941
4942
4943<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4944<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4945 values indicating the condition, and two values of the
4946 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4947 vectors and the condition is a scalar, then entire vectors are selected, not
4948 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4949
4950<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4951<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4952 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4953
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4954<p>If the condition is a vector of i1, then the value arguments must be vectors
4955 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4956
4957<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4958<pre>
4959 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4960</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4961
4962<p>Note that the code generator does not yet support conditions
4963 with vector type.</p>
4964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4965</div>
4966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4967<!-- _______________________________________________________________________ -->
4968<div class="doc_subsubsection">
4969 <a name="i_call">'<tt>call</tt>' Instruction</a>
4970</div>
4971
4972<div class="doc_text">
4973
4974<h5>Syntax:</h5>
4975<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4976 &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]4977</pre>
4978
4979<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4980<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4981
4982<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4983<p>This instruction requires several arguments:</p>
4984
4985<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4986 <li>The optional "tail" marker indicates whether the callee function accesses
4987 any allocas or varargs in the caller. If the "tail" marker is present,
4988 the function call is eligible for tail call optimization. Note that calls
4989 may be marked "tail" even if they do not occur before
4990 a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4991
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4992 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
4993 convention</a> the call should use. If none is specified, the call
4994 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4995
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4996 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4997 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
4998 '<tt>inreg</tt>' attributes are valid here.</li>
4999
5000 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5001 type of the return value. Functions that return no value are marked
5002 <tt><a href="#t_void">void</a></tt>.</li>
5003
5004 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5005 being invoked. The argument types must match the types implied by this
5006 signature. This type can be omitted if the function is not varargs and if
5007 the function type does not return a pointer to a function.</li>
5008
5009 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5010 be invoked. In most cases, this is a direct function invocation, but
5011 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5012 to function value.</li>
5013
5014 <li>'<tt>function args</tt>': argument list whose types match the function
5015 signature argument types. All arguments must be of
5016 <a href="#t_firstclass">first class</a> type. If the function signature
5017 indicates the function accepts a variable number of arguments, the extra
5018 arguments can be specified.</li>
5019
5020 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5021 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5022 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5023</ol>
5024
5025<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5026<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5027 a specified function, with its incoming arguments bound to the specified
5028 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5029 function, control flow continues with the instruction after the function
5030 call, and the return value of the function is bound to the result
5031 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5032
5033<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5034<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5035 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5036 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5037 %X = tail call i32 @foo() <i>; yields i32</i>
5038 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5039 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5040
5041 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5042 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5043 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5044 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5045 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5046 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5047</pre>
5048
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5049<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5050standard C99 library as being the C99 library functions, and may perform
5051optimizations or generate code for them under that assumption. This is
5052something we'd like to change in the future to provide better support for
5053freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5055</div>
5056
5057<!-- _______________________________________________________________________ -->
5058<div class="doc_subsubsection">
5059 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5060</div>
5061
5062<div class="doc_text">
5063
5064<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5065<pre>
5066 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5067</pre>
5068
5069<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5070<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5071 the "variable argument" area of a function call. It is used to implement the
5072 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5073
5074<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5075<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5076 argument. It returns a value of the specified argument type and increments
5077 the <tt>va_list</tt> to point to the next argument. The actual type
5078 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079
5080<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5081<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5082 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5083 to the next argument. For more information, see the variable argument
5084 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5085
5086<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]5087 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5088 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5089
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5090<p><tt>va_arg</tt> is an LLVM instruction instead of
5091 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5092 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5093
5094<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5095<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5096
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5097<p>Note that the code generator does not yet fully support va_arg on many
5098 targets. Also, it does not currently support va_arg with aggregate types on
5099 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5100
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5101</div>
5102
5103<!-- *********************************************************************** -->
5104<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5105<!-- *********************************************************************** -->
5106
5107<div class="doc_text">
5108
5109<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5110 well known names and semantics and are required to follow certain
5111 restrictions. Overall, these intrinsics represent an extension mechanism for
5112 the LLVM language that does not require changing all of the transformations
5113 in LLVM when adding to the language (or the bitcode reader/writer, the
5114 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5115
5116<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5117 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5118 begin with this prefix. Intrinsic functions must always be external
5119 functions: you cannot define the body of intrinsic functions. Intrinsic
5120 functions may only be used in call or invoke instructions: it is illegal to
5121 take the address of an intrinsic function. Additionally, because intrinsic
5122 functions are part of the LLVM language, it is required if any are added that
5123 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5124
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5125<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5126 family of functions that perform the same operation but on different data
5127 types. Because LLVM can represent over 8 million different integer types,
5128 overloading is used commonly to allow an intrinsic function to operate on any
5129 integer type. One or more of the argument types or the result type can be
5130 overloaded to accept any integer type. Argument types may also be defined as
5131 exactly matching a previous argument's type or the result type. This allows
5132 an intrinsic function which accepts multiple arguments, but needs all of them
5133 to be of the same type, to only be overloaded with respect to a single
5134 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5135
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5136<p>Overloaded intrinsics will have the names of its overloaded argument types
5137 encoded into its function name, each preceded by a period. Only those types
5138 which are overloaded result in a name suffix. Arguments whose type is matched
5139 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5140 can take an integer of any width and returns an integer of exactly the same
5141 integer width. This leads to a family of functions such as
5142 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5143 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5144 suffix is required. Because the argument's type is matched against the return
5145 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5146
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5147<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5148 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5149
5150</div>
5151
5152<!-- ======================================================================= -->
5153<div class="doc_subsection">
5154 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5155</div>
5156
5157<div class="doc_text">
5158
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5159<p>Variable argument support is defined in LLVM with
5160 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5161 intrinsic functions. These functions are related to the similarly named
5162 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5163
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5164<p>All of these functions operate on arguments that use a target-specific value
5165 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5166 not define what this type is, so all transformations should be prepared to
5167 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5168
5169<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]5170 instruction and the variable argument handling intrinsic functions are
5171 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5172
5173<div class="doc_code">
5174<pre>
5175define i32 @test(i32 %X, ...) {
5176 ; Initialize variable argument processing
5177 %ap = alloca i8*
5178 %ap2 = bitcast i8** %ap to i8*
5179 call void @llvm.va_start(i8* %ap2)
5180
5181 ; Read a single integer argument
5182 %tmp = va_arg i8** %ap, i32
5183
5184 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5185 %aq = alloca i8*
5186 %aq2 = bitcast i8** %aq to i8*
5187 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5188 call void @llvm.va_end(i8* %aq2)
5189
5190 ; Stop processing of arguments.
5191 call void @llvm.va_end(i8* %ap2)
5192 ret i32 %tmp
5193}
5194
5195declare void @llvm.va_start(i8*)
5196declare void @llvm.va_copy(i8*, i8*)
5197declare void @llvm.va_end(i8*)
5198</pre>
5199</div>
5200
5201</div>
5202
5203<!-- _______________________________________________________________________ -->
5204<div class="doc_subsubsection">
5205 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5206</div>
5207
5208
5209<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5211<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5212<pre>
5213 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5214</pre>
5215
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5216<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5217<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5218 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]5219
5220<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5221<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]5222
5223<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5224<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]5225 macro available in C. In a target-dependent way, it initializes
5226 the <tt>va_list</tt> element to which the argument points, so that the next
5227 call to <tt>va_arg</tt> will produce the first variable argument passed to
5228 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5229 need to know the last argument of the function as the compiler can figure
5230 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5231
5232</div>
5233
5234<!-- _______________________________________________________________________ -->
5235<div class="doc_subsubsection">
5236 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5237</div>
5238
5239<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5240
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5241<h5>Syntax:</h5>
5242<pre>
5243 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5244</pre>
5245
5246<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5247<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5248 which has been initialized previously
5249 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5250 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5251
5252<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5253<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5254
5255<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5256<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]5257 macro available in C. In a target-dependent way, it destroys
5258 the <tt>va_list</tt> element to which the argument points. Calls
5259 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5260 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5261 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5262
5263</div>
5264
5265<!-- _______________________________________________________________________ -->
5266<div class="doc_subsubsection">
5267 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5268</div>
5269
5270<div class="doc_text">
5271
5272<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5273<pre>
5274 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5275</pre>
5276
5277<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5278<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5279 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5280
5281<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5282<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]5283 The second argument is a pointer to a <tt>va_list</tt> element to copy
5284 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285
5286<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5287<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]5288 macro available in C. In a target-dependent way, it copies the
5289 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5290 element. This intrinsic is necessary because
5291 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5292 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5293
5294</div>
5295
5296<!-- ======================================================================= -->
5297<div class="doc_subsection">
5298 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5299</div>
5300
5301<div class="doc_text">
5302
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5303<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5304Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5305intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5306roots on the stack</a>, as well as garbage collector implementations that
5307require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5308barriers. Front-ends for type-safe garbage collected languages should generate
5309these intrinsics to make use of the LLVM garbage collectors. For more details,
5310see <a href="GarbageCollection.html">Accurate Garbage Collection with
5311LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5312
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5313<p>The garbage collection intrinsics only operate on objects in the generic
5314 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5316</div>
5317
5318<!-- _______________________________________________________________________ -->
5319<div class="doc_subsubsection">
5320 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5321</div>
5322
5323<div class="doc_text">
5324
5325<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5326<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5327 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5328</pre>
5329
5330<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5331<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]5332 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5333
5334<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5335<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5336 root pointer. The second pointer (which must be either a constant or a
5337 global value address) contains the meta-data to be associated with the
5338 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339
5340<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5341<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]5342 location. At compile-time, the code generator generates information to allow
5343 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5344 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5345 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5346
5347</div>
5348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5349<!-- _______________________________________________________________________ -->
5350<div class="doc_subsubsection">
5351 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5352</div>
5353
5354<div class="doc_text">
5355
5356<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5357<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5358 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5359</pre>
5360
5361<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5362<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5363 locations, allowing garbage collector implementations that require read
5364 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5365
5366<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5367<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]5368 allocated from the garbage collector. The first object is a pointer to the
5369 start of the referenced object, if needed by the language runtime (otherwise
5370 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5371
5372<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5373<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5374 instruction, but may be replaced with substantially more complex code by the
5375 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5376 may only be used in a function which <a href="#gc">specifies a GC
5377 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5378
5379</div>
5380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5381<!-- _______________________________________________________________________ -->
5382<div class="doc_subsubsection">
5383 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5384</div>
5385
5386<div class="doc_text">
5387
5388<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5389<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5390 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5391</pre>
5392
5393<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5394<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5395 locations, allowing garbage collector implementations that require write
5396 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5397
5398<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399<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]5400 object to store it to, and the third is the address of the field of Obj to
5401 store to. If the runtime does not require a pointer to the object, Obj may
5402 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5403
5404<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5405<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5406 instruction, but may be replaced with substantially more complex code by the
5407 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5408 may only be used in a function which <a href="#gc">specifies a GC
5409 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5410
5411</div>
5412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5413<!-- ======================================================================= -->
5414<div class="doc_subsection">
5415 <a name="int_codegen">Code Generator Intrinsics</a>
5416</div>
5417
5418<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5419
5420<p>These intrinsics are provided by LLVM to expose special features that may
5421 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5422
5423</div>
5424
5425<!-- _______________________________________________________________________ -->
5426<div class="doc_subsubsection">
5427 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5428</div>
5429
5430<div class="doc_text">
5431
5432<h5>Syntax:</h5>
5433<pre>
5434 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5435</pre>
5436
5437<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5438<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5439 target-specific value indicating the return address of the current function
5440 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5441
5442<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5443<p>The argument to this intrinsic indicates which function to return the address
5444 for. Zero indicates the calling function, one indicates its caller, etc.
5445 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5446
5447<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5448<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5449 indicating the return address of the specified call frame, or zero if it
5450 cannot be identified. The value returned by this intrinsic is likely to be
5451 incorrect or 0 for arguments other than zero, so it should only be used for
5452 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5453
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5454<p>Note that calling this intrinsic does not prevent function inlining or other
5455 aggressive transformations, so the value returned may not be that of the
5456 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5457
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5458</div>
5459
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5460<!-- _______________________________________________________________________ -->
5461<div class="doc_subsubsection">
5462 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5463</div>
5464
5465<div class="doc_text">
5466
5467<h5>Syntax:</h5>
5468<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5469 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5470</pre>
5471
5472<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5473<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5474 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5475
5476<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5477<p>The argument to this intrinsic indicates which function to return the frame
5478 pointer for. Zero indicates the calling function, one indicates its caller,
5479 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5480
5481<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5482<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5483 indicating the frame address of the specified call frame, or zero if it
5484 cannot be identified. The value returned by this intrinsic is likely to be
5485 incorrect or 0 for arguments other than zero, so it should only be used for
5486 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5488<p>Note that calling this intrinsic does not prevent function inlining or other
5489 aggressive transformations, so the value returned may not be that of the
5490 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5492</div>
5493
5494<!-- _______________________________________________________________________ -->
5495<div class="doc_subsubsection">
5496 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5497</div>
5498
5499<div class="doc_text">
5500
5501<h5>Syntax:</h5>
5502<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5503 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5504</pre>
5505
5506<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5507<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5508 of the function stack, for use
5509 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5510 useful for implementing language features like scoped automatic variable
5511 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5512
5513<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5514<p>This intrinsic returns a opaque pointer value that can be passed
5515 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5516 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5517 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5518 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5519 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5520 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521
5522</div>
5523
5524<!-- _______________________________________________________________________ -->
5525<div class="doc_subsubsection">
5526 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5527</div>
5528
5529<div class="doc_text">
5530
5531<h5>Syntax:</h5>
5532<pre>
5533 declare void @llvm.stackrestore(i8 * %ptr)
5534</pre>
5535
5536<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5537<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5538 the function stack to the state it was in when the
5539 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5540 executed. This is useful for implementing language features like scoped
5541 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5542
5543<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5544<p>See the description
5545 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5546
5547</div>
5548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549<!-- _______________________________________________________________________ -->
5550<div class="doc_subsubsection">
5551 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5552</div>
5553
5554<div class="doc_text">
5555
5556<h5>Syntax:</h5>
5557<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5558 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]5559</pre>
5560
5561<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5562<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5563 insert a prefetch instruction if supported; otherwise, it is a noop.
5564 Prefetches have no effect on the behavior of the program but can change its
5565 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566
5567<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5568<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5569 specifier determining if the fetch should be for a read (0) or write (1),
5570 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5571 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5572 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5573
5574<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5575<p>This intrinsic does not modify the behavior of the program. In particular,
5576 prefetches cannot trap and do not produce a value. On targets that support
5577 this intrinsic, the prefetch can provide hints to the processor cache for
5578 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579
5580</div>
5581
5582<!-- _______________________________________________________________________ -->
5583<div class="doc_subsubsection">
5584 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5585</div>
5586
5587<div class="doc_text">
5588
5589<h5>Syntax:</h5>
5590<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5591 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5592</pre>
5593
5594<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5595<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5596 Counter (PC) in a region of code to simulators and other tools. The method
5597 is target specific, but it is expected that the marker will use exported
5598 symbols to transmit the PC of the marker. The marker makes no guarantees
5599 that it will remain with any specific instruction after optimizations. It is
5600 possible that the presence of a marker will inhibit optimizations. The
5601 intended use is to be inserted after optimizations to allow correlations of
5602 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5603
5604<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5605<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5606
5607<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5608<p>This intrinsic does not modify the behavior of the program. Backends that do
5609 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5610
5611</div>
5612
5613<!-- _______________________________________________________________________ -->
5614<div class="doc_subsubsection">
5615 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5616</div>
5617
5618<div class="doc_text">
5619
5620<h5>Syntax:</h5>
5621<pre>
5622 declare i64 @llvm.readcyclecounter( )
5623</pre>
5624
5625<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5626<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5627 counter register (or similar low latency, high accuracy clocks) on those
5628 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5629 should map to RPCC. As the backing counters overflow quickly (on the order
5630 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5631
5632<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5633<p>When directly supported, reading the cycle counter should not modify any
5634 memory. Implementations are allowed to either return a application specific
5635 value or a system wide value. On backends without support, this is lowered
5636 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5637
5638</div>
5639
5640<!-- ======================================================================= -->
5641<div class="doc_subsection">
5642 <a name="int_libc">Standard C Library Intrinsics</a>
5643</div>
5644
5645<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5646
5647<p>LLVM provides intrinsics for a few important standard C library functions.
5648 These intrinsics allow source-language front-ends to pass information about
5649 the alignment of the pointer arguments to the code generator, providing
5650 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5651
5652</div>
5653
5654<!-- _______________________________________________________________________ -->
5655<div class="doc_subsubsection">
5656 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5657</div>
5658
5659<div class="doc_text">
5660
5661<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5662<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5663 integer bit width. Not all targets support all bit widths however.</p>
5664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5665<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5666 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5667 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5668 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5669 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5670 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5671 i32 &lt;len&gt;, i32 &lt;align&gt;)
5672 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5673 i64 &lt;len&gt;, i32 &lt;align&gt;)
5674</pre>
5675
5676<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5677<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5678 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5679
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5680<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5681 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5682
5683<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5684<p>The first argument is a pointer to the destination, the second is a pointer
5685 to the source. The third argument is an integer argument specifying the
5686 number of bytes to copy, and the fourth argument is the alignment of the
5687 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5688
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5689<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5690 then the caller guarantees that both the source and destination pointers are
5691 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5692
5693<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5694<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5695 source location to the destination location, which are not allowed to
5696 overlap. It copies "len" bytes of memory over. If the argument is known to
5697 be aligned to some boundary, this can be specified as the fourth argument,
5698 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5700</div>
5701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5702<!-- _______________________________________________________________________ -->
5703<div class="doc_subsubsection">
5704 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5705</div>
5706
5707<div class="doc_text">
5708
5709<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5710<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]5711 width. Not all targets support all bit widths however.</p>
5712
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5713<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5714 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5715 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5716 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5717 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5718 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5719 i32 &lt;len&gt;, i32 &lt;align&gt;)
5720 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5721 i64 &lt;len&gt;, i32 &lt;align&gt;)
5722</pre>
5723
5724<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5725<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5726 source location to the destination location. It is similar to the
5727 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5728 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5730<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5731 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5732
5733<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5734<p>The first argument is a pointer to the destination, the second is a pointer
5735 to the source. The third argument is an integer argument specifying the
5736 number of bytes to copy, and the fourth argument is the alignment of the
5737 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5739<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5740 then the caller guarantees that the source and destination pointers are
5741 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742
5743<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5744<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5745 source location to the destination location, which may overlap. It copies
5746 "len" bytes of memory over. If the argument is known to be aligned to some
5747 boundary, this can be specified as the fourth argument, otherwise it should
5748 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5750</div>
5751
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752<!-- _______________________________________________________________________ -->
5753<div class="doc_subsubsection">
5754 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5755</div>
5756
5757<div class="doc_text">
5758
5759<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5760<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]5761 width. Not all targets support all bit widths however.</p>
5762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5763<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5764 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5765 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5766 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5767 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5768 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5769 i32 &lt;len&gt;, i32 &lt;align&gt;)
5770 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5771 i64 &lt;len&gt;, i32 &lt;align&gt;)
5772</pre>
5773
5774<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5775<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5776 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5777
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5778<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5779 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5780
5781<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5782<p>The first argument is a pointer to the destination to fill, the second is the
5783 byte value to fill it with, the third argument is an integer argument
5784 specifying the number of bytes to fill, and the fourth argument is the known
5785 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5786
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5787<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5788 then the caller guarantees that the destination pointer is aligned to that
5789 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5790
5791<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5792<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5793 at the destination location. If the argument is known to be aligned to some
5794 boundary, this can be specified as the fourth argument, otherwise it should
5795 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5796
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5797</div>
5798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5799<!-- _______________________________________________________________________ -->
5800<div class="doc_subsubsection">
5801 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5802</div>
5803
5804<div class="doc_text">
5805
5806<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5807<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5808 floating point or vector of floating point type. Not all targets support all
5809 types however.</p>
5810
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5811<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5812 declare float @llvm.sqrt.f32(float %Val)
5813 declare double @llvm.sqrt.f64(double %Val)
5814 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5815 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5816 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5817</pre>
5818
5819<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5820<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5821 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5822 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5823 behavior for negative numbers other than -0.0 (which allows for better
5824 optimization, because there is no need to worry about errno being
5825 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]5826
5827<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5828<p>The argument and return value are floating point numbers of the same
5829 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5830
5831<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5832<p>This function returns the sqrt of the specified operand if it is a
5833 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5835</div>
5836
5837<!-- _______________________________________________________________________ -->
5838<div class="doc_subsubsection">
5839 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5840</div>
5841
5842<div class="doc_text">
5843
5844<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5845<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5846 floating point or vector of floating point type. Not all targets support all
5847 types however.</p>
5848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5849<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5850 declare float @llvm.powi.f32(float %Val, i32 %power)
5851 declare double @llvm.powi.f64(double %Val, i32 %power)
5852 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5853 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5854 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855</pre>
5856
5857<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5858<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5859 specified (positive or negative) power. The order of evaluation of
5860 multiplications is not defined. When a vector of floating point type is
5861 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5862
5863<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5864<p>The second argument is an integer power, and the first is a value to raise to
5865 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5866
5867<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5868<p>This function returns the first value raised to the second power with an
5869 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5870
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5871</div>
5872
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5873<!-- _______________________________________________________________________ -->
5874<div class="doc_subsubsection">
5875 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5876</div>
5877
5878<div class="doc_text">
5879
5880<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5881<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5882 floating point or vector of floating point type. Not all targets support all
5883 types however.</p>
5884
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5885<pre>
5886 declare float @llvm.sin.f32(float %Val)
5887 declare double @llvm.sin.f64(double %Val)
5888 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5889 declare fp128 @llvm.sin.f128(fp128 %Val)
5890 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5891</pre>
5892
5893<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5894<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5895
5896<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5897<p>The argument and return value are floating point numbers of the same
5898 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5899
5900<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5901<p>This function returns the sine of the specified operand, returning the same
5902 values as the libm <tt>sin</tt> functions would, and handles error conditions
5903 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5904
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5905</div>
5906
5907<!-- _______________________________________________________________________ -->
5908<div class="doc_subsubsection">
5909 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5910</div>
5911
5912<div class="doc_text">
5913
5914<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5915<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5916 floating point or vector of floating point type. Not all targets support all
5917 types however.</p>
5918
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5919<pre>
5920 declare float @llvm.cos.f32(float %Val)
5921 declare double @llvm.cos.f64(double %Val)
5922 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5923 declare fp128 @llvm.cos.f128(fp128 %Val)
5924 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5925</pre>
5926
5927<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5928<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5929
5930<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5931<p>The argument and return value are floating point numbers of the same
5932 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5933
5934<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5935<p>This function returns the cosine of the specified operand, returning the same
5936 values as the libm <tt>cos</tt> functions would, and handles error conditions
5937 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5938
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5939</div>
5940
5941<!-- _______________________________________________________________________ -->
5942<div class="doc_subsubsection">
5943 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5944</div>
5945
5946<div class="doc_text">
5947
5948<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5949<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5950 floating point or vector of floating point type. Not all targets support all
5951 types however.</p>
5952
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5953<pre>
5954 declare float @llvm.pow.f32(float %Val, float %Power)
5955 declare double @llvm.pow.f64(double %Val, double %Power)
5956 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5957 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5958 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5959</pre>
5960
5961<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5962<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5963 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5964
5965<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5966<p>The second argument is a floating point power, and the first is a value to
5967 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5968
5969<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5970<p>This function returns the first value raised to the second power, returning
5971 the same values as the libm <tt>pow</tt> functions would, and handles error
5972 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5973
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5974</div>
5975
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5976<!-- ======================================================================= -->
5977<div class="doc_subsection">
5978 <a name="int_manip">Bit Manipulation Intrinsics</a>
5979</div>
5980
5981<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5982
5983<p>LLVM provides intrinsics for a few important bit manipulation operations.
5984 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5985
5986</div>
5987
5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
5990 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5991</div>
5992
5993<div class="doc_text">
5994
5995<h5>Syntax:</h5>
5996<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5997 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
5998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5999<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6000 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6001 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6002 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6003</pre>
6004
6005<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6006<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6007 values with an even number of bytes (positive multiple of 16 bits). These
6008 are useful for performing operations on data that is not in the target's
6009 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6010
6011<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6012<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6013 and low byte of the input i16 swapped. Similarly,
6014 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6015 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6016 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6017 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6018 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6019 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6020
6021</div>
6022
6023<!-- _______________________________________________________________________ -->
6024<div class="doc_subsubsection">
6025 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6026</div>
6027
6028<div class="doc_text">
6029
6030<h5>Syntax:</h5>
6031<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]6032 width. Not all targets support all bit widths however.</p>
6033
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6034<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6035 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6036 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6037 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6038 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6039 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6040</pre>
6041
6042<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6043<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6044 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6045
6046<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6047<p>The only argument is the value to be counted. The argument may be of any
6048 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6049
6050<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6051<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]6052
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6053</div>
6054
6055<!-- _______________________________________________________________________ -->
6056<div class="doc_subsubsection">
6057 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6058</div>
6059
6060<div class="doc_text">
6061
6062<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6063<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6064 integer bit width. Not all targets support all bit widths however.</p>
6065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6066<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6067 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6068 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6069 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6070 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6071 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6072</pre>
6073
6074<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6075<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6076 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6077
6078<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6079<p>The only argument is the value to be counted. The argument may be of any
6080 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081
6082<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6083<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6084 zeros in a variable. If the src == 0 then the result is the size in bits of
6085 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6087</div>
6088
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6089<!-- _______________________________________________________________________ -->
6090<div class="doc_subsubsection">
6091 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6092</div>
6093
6094<div class="doc_text">
6095
6096<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6097<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6098 integer bit width. Not all targets support all bit widths however.</p>
6099
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6100<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6101 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6102 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6103 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6104 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6105 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6106</pre>
6107
6108<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6109<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6110 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6111
6112<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6113<p>The only argument is the value to be counted. The argument may be of any
6114 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6115
6116<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6117<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6118 zeros in a variable. If the src == 0 then the result is the size in bits of
6119 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6121</div>
6122
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6123<!-- ======================================================================= -->
6124<div class="doc_subsection">
6125 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6126</div>
6127
6128<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6129
6130<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6131
6132</div>
6133
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6134<!-- _______________________________________________________________________ -->
6135<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6136 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6137</div>
6138
6139<div class="doc_text">
6140
6141<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6142<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]6143 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6144
6145<pre>
6146 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6147 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6148 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6149</pre>
6150
6151<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6152<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6153 a signed addition of the two arguments, and indicate whether an overflow
6154 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6155
6156<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6157<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]6158 be of integer types of any bit width, but they must have the same bit
6159 width. The second element of the result structure must be of
6160 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6161 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6162
6163<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6164<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6165 a signed addition of the two variables. They return a structure &mdash; the
6166 first element of which is the signed summation, and the second element of
6167 which is a bit specifying if the signed summation resulted in an
6168 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6169
6170<h5>Examples:</h5>
6171<pre>
6172 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6173 %sum = extractvalue {i32, i1} %res, 0
6174 %obit = extractvalue {i32, i1} %res, 1
6175 br i1 %obit, label %overflow, label %normal
6176</pre>
6177
6178</div>
6179
6180<!-- _______________________________________________________________________ -->
6181<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6182 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6183</div>
6184
6185<div class="doc_text">
6186
6187<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6188<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]6189 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6190
6191<pre>
6192 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6193 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6194 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6195</pre>
6196
6197<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6198<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6199 an unsigned addition of the two arguments, and indicate whether a carry
6200 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6201
6202<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6203<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]6204 be of integer types of any bit width, but they must have the same bit
6205 width. The second element of the result structure must be of
6206 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6207 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6208
6209<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6210<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6211 an unsigned addition of the two arguments. They return a structure &mdash;
6212 the first element of which is the sum, and the second element of which is a
6213 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6214
6215<h5>Examples:</h5>
6216<pre>
6217 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6218 %sum = extractvalue {i32, i1} %res, 0
6219 %obit = extractvalue {i32, i1} %res, 1
6220 br i1 %obit, label %carry, label %normal
6221</pre>
6222
6223</div>
6224
6225<!-- _______________________________________________________________________ -->
6226<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6227 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6228</div>
6229
6230<div class="doc_text">
6231
6232<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6233<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]6234 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6235
6236<pre>
6237 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6238 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6239 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6240</pre>
6241
6242<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6243<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6244 a signed subtraction of the two arguments, and indicate whether an overflow
6245 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6246
6247<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6248<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]6249 be of integer types of any bit width, but they must have the same bit
6250 width. The second element of the result structure must be of
6251 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6252 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6253
6254<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6255<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6256 a signed subtraction of the two arguments. They return a structure &mdash;
6257 the first element of which is the subtraction, and the second element of
6258 which is a bit specifying if the signed subtraction resulted in an
6259 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6260
6261<h5>Examples:</h5>
6262<pre>
6263 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6264 %sum = extractvalue {i32, i1} %res, 0
6265 %obit = extractvalue {i32, i1} %res, 1
6266 br i1 %obit, label %overflow, label %normal
6267</pre>
6268
6269</div>
6270
6271<!-- _______________________________________________________________________ -->
6272<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6273 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6274</div>
6275
6276<div class="doc_text">
6277
6278<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6279<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]6280 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6281
6282<pre>
6283 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6284 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6285 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6286</pre>
6287
6288<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6289<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6290 an unsigned subtraction of the two arguments, and indicate whether an
6291 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6292
6293<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6294<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6295 be of integer types of any bit width, but they must have the same bit
6296 width. The second element of the result structure must be of
6297 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6298 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6299
6300<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6301<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6302 an unsigned subtraction of the two arguments. They return a structure &mdash;
6303 the first element of which is the subtraction, and the second element of
6304 which is a bit specifying if the unsigned subtraction resulted in an
6305 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6306
6307<h5>Examples:</h5>
6308<pre>
6309 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6310 %sum = extractvalue {i32, i1} %res, 0
6311 %obit = extractvalue {i32, i1} %res, 1
6312 br i1 %obit, label %overflow, label %normal
6313</pre>
6314
6315</div>
6316
6317<!-- _______________________________________________________________________ -->
6318<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6319 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6320</div>
6321
6322<div class="doc_text">
6323
6324<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6325<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]6326 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6327
6328<pre>
6329 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6330 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6331 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6332</pre>
6333
6334<h5>Overview:</h5>
6335
6336<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6337 a signed multiplication of the two arguments, and indicate whether an
6338 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6339
6340<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6341<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]6342 be of integer types of any bit width, but they must have the same bit
6343 width. The second element of the result structure must be of
6344 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6345 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6346
6347<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6348<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6349 a signed multiplication of the two arguments. They return a structure &mdash;
6350 the first element of which is the multiplication, and the second element of
6351 which is a bit specifying if the signed multiplication resulted in an
6352 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6353
6354<h5>Examples:</h5>
6355<pre>
6356 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6357 %sum = extractvalue {i32, i1} %res, 0
6358 %obit = extractvalue {i32, i1} %res, 1
6359 br i1 %obit, label %overflow, label %normal
6360</pre>
6361
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6362</div>
6363
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6364<!-- _______________________________________________________________________ -->
6365<div class="doc_subsubsection">
6366 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6367</div>
6368
6369<div class="doc_text">
6370
6371<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6372<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]6373 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6374
6375<pre>
6376 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6377 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6378 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6379</pre>
6380
6381<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6382<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6383 a unsigned multiplication of the two arguments, and indicate whether an
6384 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6385
6386<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6387<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]6388 be of integer types of any bit width, but they must have the same bit
6389 width. The second element of the result structure must be of
6390 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6391 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6392
6393<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6394<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6395 an unsigned multiplication of the two arguments. They return a structure
6396 &mdash; the first element of which is the multiplication, and the second
6397 element of which is a bit specifying if the unsigned multiplication resulted
6398 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6399
6400<h5>Examples:</h5>
6401<pre>
6402 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6403 %sum = extractvalue {i32, i1} %res, 0
6404 %obit = extractvalue {i32, i1} %res, 1
6405 br i1 %obit, label %overflow, label %normal
6406</pre>
6407
6408</div>
6409
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6410<!-- ======================================================================= -->
6411<div class="doc_subsection">
6412 <a name="int_debugger">Debugger Intrinsics</a>
6413</div>
6414
6415<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6416
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6417<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6418 prefix), are described in
6419 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6420 Level Debugging</a> document.</p>
6421
6422</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6423
6424<!-- ======================================================================= -->
6425<div class="doc_subsection">
6426 <a name="int_eh">Exception Handling Intrinsics</a>
6427</div>
6428
6429<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6430
6431<p>The LLVM exception handling intrinsics (which all start with
6432 <tt>llvm.eh.</tt> prefix), are described in
6433 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6434 Handling</a> document.</p>
6435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6436</div>
6437
6438<!-- ======================================================================= -->
6439<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6440 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6441</div>
6442
6443<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6444
6445<p>This intrinsic makes it possible to excise one parameter, marked with
6446 the <tt>nest</tt> attribute, from a function. The result is a callable
6447 function pointer lacking the nest parameter - the caller does not need to
6448 provide a value for it. Instead, the value to use is stored in advance in a
6449 "trampoline", a block of memory usually allocated on the stack, which also
6450 contains code to splice the nest value into the argument list. This is used
6451 to implement the GCC nested function address extension.</p>
6452
6453<p>For example, if the function is
6454 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6455 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6456 follows:</p>
6457
6458<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6459<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6460 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6461 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6462 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6463 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6464</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6465</div>
6466
6467<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6468 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6469
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6470</div>
6471
6472<!-- _______________________________________________________________________ -->
6473<div class="doc_subsubsection">
6474 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6475</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6476
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6477<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6478
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6479<h5>Syntax:</h5>
6480<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6481 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]6482</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6483
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6484<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6485<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6486 function pointer suitable for executing it.</p>
6487
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6488<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6489<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6490 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6491 sufficiently aligned block of memory; this memory is written to by the
6492 intrinsic. Note that the size and the alignment are target-specific - LLVM
6493 currently provides no portable way of determining them, so a front-end that
6494 generates this intrinsic needs to have some target-specific knowledge.
6495 The <tt>func</tt> argument must hold a function bitcast to
6496 an <tt>i8*</tt>.</p>
6497
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6498<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6499<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6500 dependent code, turning it into a function. A pointer to this function is
6501 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6502 function pointer type</a> before being called. The new function's signature
6503 is the same as that of <tt>func</tt> with any arguments marked with
6504 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6505 is allowed, and it must be of pointer type. Calling the new function is
6506 equivalent to calling <tt>func</tt> with the same argument list, but
6507 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6508 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6509 by <tt>tramp</tt> is modified, then the effect of any later call to the
6510 returned function pointer is undefined.</p>
6511
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6512</div>
6513
6514<!-- ======================================================================= -->
6515<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6516 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6517</div>
6518
6519<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6520
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6521<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6522 hardware constructs for atomic operations and memory synchronization. This
6523 provides an interface to the hardware, not an interface to the programmer. It
6524 is aimed at a low enough level to allow any programming models or APIs
6525 (Application Programming Interfaces) which need atomic behaviors to map
6526 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6527 hardware provides a "universal IR" for source languages, it also provides a
6528 starting point for developing a "universal" atomic operation and
6529 synchronization IR.</p>
6530
6531<p>These do <em>not</em> form an API such as high-level threading libraries,
6532 software transaction memory systems, atomic primitives, and intrinsic
6533 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6534 application libraries. The hardware interface provided by LLVM should allow
6535 a clean implementation of all of these APIs and parallel programming models.
6536 No one model or paradigm should be selected above others unless the hardware
6537 itself ubiquitously does so.</p>
6538
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6539</div>
6540
6541<!-- _______________________________________________________________________ -->
6542<div class="doc_subsubsection">
6543 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6544</div>
6545<div class="doc_text">
6546<h5>Syntax:</h5>
6547<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6548 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]6549</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6550
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6551<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6552<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6553 specific pairs of memory access types.</p>
6554
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6555<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6556<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6557 The first four arguments enables a specific barrier as listed below. The
6558 fith argument specifies that the barrier applies to io or device or uncached
6559 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6560
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6561<ul>
6562 <li><tt>ll</tt>: load-load barrier</li>
6563 <li><tt>ls</tt>: load-store barrier</li>
6564 <li><tt>sl</tt>: store-load barrier</li>
6565 <li><tt>ss</tt>: store-store barrier</li>
6566 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6567</ul>
6568
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6569<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6570<p>This intrinsic causes the system to enforce some ordering constraints upon
6571 the loads and stores of the program. This barrier does not
6572 indicate <em>when</em> any events will occur, it only enforces
6573 an <em>order</em> in which they occur. For any of the specified pairs of load
6574 and store operations (f.ex. load-load, or store-load), all of the first
6575 operations preceding the barrier will complete before any of the second
6576 operations succeeding the barrier begin. Specifically the semantics for each
6577 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6578
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6579<ul>
6580 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6581 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6582 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6583 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6584 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6585 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6586 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6587 load after the barrier begins.</li>
6588</ul>
6589
6590<p>These semantics are applied with a logical "and" behavior when more than one
6591 is enabled in a single memory barrier intrinsic.</p>
6592
6593<p>Backends may implement stronger barriers than those requested when they do
6594 not support as fine grained a barrier as requested. Some architectures do
6595 not need all types of barriers and on such architectures, these become
6596 noops.</p>
6597
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6598<h5>Example:</h5>
6599<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6600%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6601%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6602 store i32 4, %ptr
6603
6604%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6605 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6606 <i>; guarantee the above finishes</i>
6607 store i32 8, %ptr <i>; before this begins</i>
6608</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6609
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6610</div>
6611
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6612<!-- _______________________________________________________________________ -->
6613<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6614 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6615</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6616
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6617<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6618
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6619<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6620<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6621 any integer bit width and for different address spaces. Not all targets
6622 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6623
6624<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6625 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6626 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6627 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6628 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]6629</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6630
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6631<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6632<p>This loads a value in memory and compares it to a given value. If they are
6633 equal, it stores a new value into the memory.</p>
6634
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6635<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6636<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6637 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6638 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6639 this integer type. While any bit width integer may be used, targets may only
6640 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6641
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6642<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6643<p>This entire intrinsic must be executed atomically. It first loads the value
6644 in memory pointed to by <tt>ptr</tt> and compares it with the
6645 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6646 memory. The loaded value is yielded in all cases. This provides the
6647 equivalent of an atomic compare-and-swap operation within the SSA
6648 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6649
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6650<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6651<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6652%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6653%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6654 store i32 4, %ptr
6655
6656%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6657%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6658 <i>; yields {i32}:result1 = 4</i>
6659%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6660%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6661
6662%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6663%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6664 <i>; yields {i32}:result2 = 8</i>
6665%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6666
6667%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6668</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6669
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6670</div>
6671
6672<!-- _______________________________________________________________________ -->
6673<div class="doc_subsubsection">
6674 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6675</div>
6676<div class="doc_text">
6677<h5>Syntax:</h5>
6678
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6679<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6680 integer bit width. Not all targets support all bit widths however.</p>
6681
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6682<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6683 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6684 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6685 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6686 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]6687</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6688
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6689<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6690<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6691 the value from memory. It then stores the value in <tt>val</tt> in the memory
6692 at <tt>ptr</tt>.</p>
6693
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6694<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6695<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6696 the <tt>val</tt> argument and the result must be integers of the same bit
6697 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6698 integer type. The targets may only lower integer representations they
6699 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6700
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6701<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6702<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6703 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6704 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6705
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6706<h5>Examples:</h5>
6707<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6708%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6709%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6710 store i32 4, %ptr
6711
6712%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6713%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6714 <i>; yields {i32}:result1 = 4</i>
6715%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6716%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6717
6718%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6719%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6720 <i>; yields {i32}:result2 = 8</i>
6721
6722%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6723%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6724</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6725
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6726</div>
6727
6728<!-- _______________________________________________________________________ -->
6729<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6730 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6731
6732</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6733
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6734<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6735
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6736<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6737<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6738 any integer bit width. Not all targets support all bit widths however.</p>
6739
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6740<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6741 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6742 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6743 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6744 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]6745</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6746
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6747<h5>Overview:</h5>
6748<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6749 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6750
6751<h5>Arguments:</h5>
6752<p>The intrinsic takes two arguments, the first a pointer to an integer value
6753 and the second an integer value. The result is also an integer value. These
6754 integer types can have any bit width, but they must all have the same bit
6755 width. The targets may only lower integer representations they support.</p>
6756
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6757<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6758<p>This intrinsic does a series of operations atomically. It first loads the
6759 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6760 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]6761
6762<h5>Examples:</h5>
6763<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6764%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6765%ptr = bitcast i8* %mallocP to i32*
6766 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6767%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6768 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6769%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6770 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6771%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6772 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6773%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6774</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6775
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6776</div>
6777
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6778<!-- _______________________________________________________________________ -->
6779<div class="doc_subsubsection">
6780 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6781
6782</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6783
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6784<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6785
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6786<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6787<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6788 any integer bit width and for different address spaces. Not all targets
6789 support all bit widths however.</p>
6790
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6791<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6792 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6793 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6794 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6795 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]6796</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6797
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6798<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6799<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6800 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6801
6802<h5>Arguments:</h5>
6803<p>The intrinsic takes two arguments, the first a pointer to an integer value
6804 and the second an integer value. The result is also an integer value. These
6805 integer types can have any bit width, but they must all have the same bit
6806 width. The targets may only lower integer representations they support.</p>
6807
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6808<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6809<p>This intrinsic does a series of operations atomically. It first loads the
6810 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6811 result to <tt>ptr</tt>. It yields the original value stored
6812 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6813
6814<h5>Examples:</h5>
6815<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6816%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6817%ptr = bitcast i8* %mallocP to i32*
6818 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6819%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6820 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6821%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6822 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6823%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6824 <i>; yields {i32}:result3 = 2</i>
6825%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6826</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6827
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6828</div>
6829
6830<!-- _______________________________________________________________________ -->
6831<div class="doc_subsubsection">
6832 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6833 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6834 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6835 <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]6836</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6837
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6838<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6839
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6840<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841<p>These are overloaded intrinsics. You can
6842 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6843 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6844 bit width and for different address spaces. Not all targets support all bit
6845 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6846
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6847<pre>
6848 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6849 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6850 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6851 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]6852</pre>
6853
6854<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6855 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6856 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6857 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6858 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]6859</pre>
6860
6861<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6862 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6863 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6864 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6865 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]6866</pre>
6867
6868<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6869 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6870 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6871 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6872 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]6873</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6874
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6875<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6876<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6877 the value stored in memory at <tt>ptr</tt>. It yields the original value
6878 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6879
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6880<h5>Arguments:</h5>
6881<p>These intrinsics take two arguments, the first a pointer to an integer value
6882 and the second an integer value. The result is also an integer value. These
6883 integer types can have any bit width, but they must all have the same bit
6884 width. The targets may only lower integer representations they support.</p>
6885
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6886<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6887<p>These intrinsics does a series of operations atomically. They first load the
6888 value stored at <tt>ptr</tt>. They then do the bitwise
6889 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6890 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6891
6892<h5>Examples:</h5>
6893<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6894%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6895%ptr = bitcast i8* %mallocP to i32*
6896 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6897%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6898 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6899%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6900 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6901%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6902 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6903%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6904 <i>; yields {i32}:result3 = FF</i>
6905%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6906</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6907
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6908</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6909
6910<!-- _______________________________________________________________________ -->
6911<div class="doc_subsubsection">
6912 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6913 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6914 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6915 <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]6916</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6917
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6918<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6919
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6920<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6921<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6922 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6923 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6924 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6925
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6926<pre>
6927 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930 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]6931</pre>
6932
6933<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6934 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6935 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6936 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6937 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]6938</pre>
6939
6940<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6941 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6942 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6943 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6944 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]6945</pre>
6946
6947<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6948 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6949 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6950 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6951 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]6952</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6953
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6954<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6955<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6956 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6957 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6958
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6959<h5>Arguments:</h5>
6960<p>These intrinsics take two arguments, the first a pointer to an integer value
6961 and the second an integer value. The result is also an integer value. These
6962 integer types can have any bit width, but they must all have the same bit
6963 width. The targets may only lower integer representations they support.</p>
6964
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6965<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6966<p>These intrinsics does a series of operations atomically. They first load the
6967 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
6968 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
6969 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6970
6971<h5>Examples:</h5>
6972<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6973%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6974%ptr = bitcast i8* %mallocP to i32*
6975 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6976%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6977 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6978%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6979 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6980%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6981 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6982%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6983 <i>; yields {i32}:result3 = 8</i>
6984%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6985</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6986
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6987</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6988
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]6989
6990<!-- ======================================================================= -->
6991<div class="doc_subsection">
6992 <a name="int_memorymarkers">Memory Use Markers</a>
6993</div>
6994
6995<div class="doc_text">
6996
6997<p>This class of intrinsics exists to information about the lifetime of memory
6998 objects and ranges where variables are immutable.</p>
6999
7000</div>
7001
7002<!-- _______________________________________________________________________ -->
7003<div class="doc_subsubsection">
7004 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7005</div>
7006
7007<div class="doc_text">
7008
7009<h5>Syntax:</h5>
7010<pre>
7011 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7012</pre>
7013
7014<h5>Overview:</h5>
7015<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7016 object's lifetime.</p>
7017
7018<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7019<p>The first argument is a constant integer representing the size of the
7020 object, or -1 if it is variable sized. The second argument is a pointer to
7021 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7022
7023<h5>Semantics:</h5>
7024<p>This intrinsic indicates that before this point in the code, the value of the
7025 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]7026 never be used and has an undefined value. A load from the pointer that
7027 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7028 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7029
7030</div>
7031
7032<!-- _______________________________________________________________________ -->
7033<div class="doc_subsubsection">
7034 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7035</div>
7036
7037<div class="doc_text">
7038
7039<h5>Syntax:</h5>
7040<pre>
7041 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7042</pre>
7043
7044<h5>Overview:</h5>
7045<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7046 object's lifetime.</p>
7047
7048<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7049<p>The first argument is a constant integer representing the size of the
7050 object, or -1 if it is variable sized. The second argument is a pointer to
7051 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7052
7053<h5>Semantics:</h5>
7054<p>This intrinsic indicates that after this point in the code, the value of the
7055 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7056 never be used and has an undefined value. Any stores into the memory object
7057 following this intrinsic may be removed as dead.
7058
7059</div>
7060
7061<!-- _______________________________________________________________________ -->
7062<div class="doc_subsubsection">
7063 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7064</div>
7065
7066<div class="doc_text">
7067
7068<h5>Syntax:</h5>
7069<pre>
7070 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7071</pre>
7072
7073<h5>Overview:</h5>
7074<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7075 a memory object will not change.</p>
7076
7077<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7078<p>The first argument is a constant integer representing the size of the
7079 object, or -1 if it is variable sized. The second argument is a pointer to
7080 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7081
7082<h5>Semantics:</h5>
7083<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7084 the return value, the referenced memory location is constant and
7085 unchanging.</p>
7086
7087</div>
7088
7089<!-- _______________________________________________________________________ -->
7090<div class="doc_subsubsection">
7091 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7092</div>
7093
7094<div class="doc_text">
7095
7096<h5>Syntax:</h5>
7097<pre>
7098 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7099</pre>
7100
7101<h5>Overview:</h5>
7102<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7103 a memory object are mutable.</p>
7104
7105<h5>Arguments:</h5>
7106<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7107 The second argument is a constant integer representing the size of the
7108 object, or -1 if it is variable sized and the third argument is a pointer
7109 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7110
7111<h5>Semantics:</h5>
7112<p>This intrinsic indicates that the memory is mutable again.</p>
7113
7114</div>
7115
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7116<!-- ======================================================================= -->
7117<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7118 <a name="int_general">General Intrinsics</a>
7119</div>
7120
7121<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7122
7123<p>This class of intrinsics is designed to be generic and has no specific
7124 purpose.</p>
7125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7126</div>
7127
7128<!-- _______________________________________________________________________ -->
7129<div class="doc_subsubsection">
7130 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7131</div>
7132
7133<div class="doc_text">
7134
7135<h5>Syntax:</h5>
7136<pre>
7137 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7138</pre>
7139
7140<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7141<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7142
7143<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7144<p>The first argument is a pointer to a value, the second is a pointer to a
7145 global string, the third is a pointer to a global string which is the source
7146 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7147
7148<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7149<p>This intrinsic allows annotation of local variables with arbitrary strings.
7150 This can be useful for special purpose optimizations that want to look for
7151 these annotations. These have no other defined use, they are ignored by code
7152 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7154</div>
7155
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7156<!-- _______________________________________________________________________ -->
7157<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7158 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7159</div>
7160
7161<div class="doc_text">
7162
7163<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7164<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7165 any integer bit width.</p>
7166
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7167<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7168 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7169 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7170 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7171 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7172 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]7173</pre>
7174
7175<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7176<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7177
7178<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7179<p>The first argument is an integer value (result of some expression), the
7180 second is a pointer to a global string, the third is a pointer to a global
7181 string which is the source file name, and the last argument is the line
7182 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7183
7184<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7185<p>This intrinsic allows annotations to be put on arbitrary expressions with
7186 arbitrary strings. This can be useful for special purpose optimizations that
7187 want to look for these annotations. These have no other defined use, they
7188 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7189
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7190</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7191
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7192<!-- _______________________________________________________________________ -->
7193<div class="doc_subsubsection">
7194 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7195</div>
7196
7197<div class="doc_text">
7198
7199<h5>Syntax:</h5>
7200<pre>
7201 declare void @llvm.trap()
7202</pre>
7203
7204<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7205<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7206
7207<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7208<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7209
7210<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7211<p>This intrinsics is lowered to the target dependent trap instruction. If the
7212 target does not have a trap instruction, this intrinsic will be lowered to
7213 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7214
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7215</div>
7216
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7217<!-- _______________________________________________________________________ -->
7218<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7219 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7220</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7221
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7222<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7223
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7224<h5>Syntax:</h5>
7225<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7226 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7227</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7228
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7229<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7230<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7231 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7232 ensure that it is placed on the stack before local variables.</p>
7233
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7234<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7235<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7236 arguments. The first argument is the value loaded from the stack
7237 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7238 that has enough space to hold the value of the guard.</p>
7239
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7240<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7241<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7242 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7243 stack. This is to ensure that if a local variable on the stack is
7244 overwritten, it will destroy the value of the guard. When the function exits,
7245 the guard on the stack is checked against the original guard. If they're
7246 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7247 function.</p>
7248
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7249</div>
7250
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7251<!-- _______________________________________________________________________ -->
7252<div class="doc_subsubsection">
7253 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7254</div>
7255
7256<div class="doc_text">
7257
7258<h5>Syntax:</h5>
7259<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame^]7260 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7261 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7262</pre>
7263
7264<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7265<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
7266 to the optimizers to either discover at compile time either a) when an
7267 operation like memcpy will either overflow a buffer that corresponds to
7268 an object, or b) to determine that a runtime check for overflow isn't
7269 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame^]7270 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7271
7272<h5>Arguments:</h5>
7273<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame^]7274 argument is a pointer to or into the <tt>object</tt>. The second argument
7275 is a boolean 0 or 1. This argument determines whether you want the
7276 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7277 1, variables are not allowed.</p>
7278
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7279<h5>Semantics:</h5>
7280<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7281 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7282 (depending on the <tt>type</tt> argument if the size cannot be determined
7283 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7284
7285</div>
7286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7287<!-- *********************************************************************** -->
7288<hr>
7289<address>
7290 <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]7292 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7294
7295 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7296 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7297 Last modified: $Date$
7298</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7300</body>
7301</html>