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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 797ddec380dfcd01f74055185b31d8d3ce33186f / . / 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>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]46 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]47 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]48 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]49 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
51 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]52 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]53 </ol>
54 </li>
55 <li><a href="#typesystem">Type System</a>
56 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]57 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]58 <li><a href="#t_primitive">Primitive Types</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 <ol>
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]60 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]61 <li><a href="#t_floating">Floating Point Types</a></li>
62 <li><a href="#t_void">Void Type</a></li>
63 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]64 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]65 </ol>
66 </li>
67 <li><a href="#t_derived">Derived Types</a>
68 <ol>
69 <li><a href="#t_array">Array Type</a></li>
70 <li><a href="#t_function">Function Type</a></li>
71 <li><a href="#t_pointer">Pointer Type</a></li>
72 <li><a href="#t_struct">Structure Type</a></li>
73 <li><a href="#t_pstruct">Packed Structure Type</a></li>
74 <li><a href="#t_vector">Vector Type</a></li>
75 <li><a href="#t_opaque">Opaque Type</a></li>
76 </ol>
77 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]78 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]79 </ol>
80 </li>
81 <li><a href="#constants">Constants</a>
82 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]83 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]84 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]85 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
86 <li><a href="#undefvalues">Undefined Values</a></li>
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]87 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]88 <li><a href="#constantexprs">Constant Expressions</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>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]94 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]95 </ol>
96 </li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]97 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
98 <ol>
99 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]100 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
101 Global Variable</a></li>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]102 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
103 Global Variable</a></li>
104 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
105 Global Variable</a></li>
106 </ol>
107 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]108 <li><a href="#instref">Instruction Reference</a>
109 <ol>
110 <li><a href="#terminators">Terminator Instructions</a>
111 <ol>
112 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
113 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
114 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]115 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]116 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
117 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
118 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
119 </ol>
120 </li>
121 <li><a href="#binaryops">Binary Operations</a>
122 <ol>
123 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]124 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]125 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]126 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]127 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]128 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]129 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
130 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
131 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
132 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
133 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
134 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
135 </ol>
136 </li>
137 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
138 <ol>
139 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
140 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
141 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
142 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
143 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
144 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
145 </ol>
146 </li>
147 <li><a href="#vectorops">Vector Operations</a>
148 <ol>
149 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
150 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
151 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
152 </ol>
153 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]154 <li><a href="#aggregateops">Aggregate Operations</a>
155 <ol>
156 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
157 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
158 </ol>
159 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]160 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
161 <ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]162 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
163 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
164 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
165 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
166 </ol>
167 </li>
168 <li><a href="#convertops">Conversion Operations</a>
169 <ol>
170 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
171 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
172 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
173 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
174 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
175 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
176 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
177 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
178 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
179 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
180 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
181 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
182 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]183 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]184 <li><a href="#otherops">Other Operations</a>
185 <ol>
186 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
187 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
188 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
189 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
190 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
191 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
192 </ol>
193 </li>
194 </ol>
195 </li>
196 <li><a href="#intrinsics">Intrinsic Functions</a>
197 <ol>
198 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
199 <ol>
200 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
201 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
202 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
203 </ol>
204 </li>
205 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
206 <ol>
207 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
208 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
209 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
210 </ol>
211 </li>
212 <li><a href="#int_codegen">Code Generator Intrinsics</a>
213 <ol>
214 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
215 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
216 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
217 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
218 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
219 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
220 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
221 </ol>
222 </li>
223 <li><a href="#int_libc">Standard C Library Intrinsics</a>
224 <ol>
225 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
226 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
227 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
228 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
229 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]230 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
231 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
232 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]233 </ol>
234 </li>
235 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
236 <ol>
237 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
238 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
239 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
240 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]241 </ol>
242 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]243 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
244 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]245 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
246 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
247 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
248 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
249 <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]250 <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]251 </ol>
252 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]253 <li><a href="#int_debugger">Debugger intrinsics</a></li>
254 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]255 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]256 <ol>
257 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]258 </ol>
259 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]260 <li><a href="#int_atomics">Atomic intrinsics</a>
261 <ol>
262 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
263 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
264 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
265 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
266 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
267 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
268 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
269 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
270 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
271 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
272 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
273 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
274 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
275 </ol>
276 </li>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]277 <li><a href="#int_memorymarkers">Memory Use Markers</a>
278 <ol>
279 <li><a href="#int_lifetime_start"><tt>llvm.lifetime.start</tt></a></li>
280 <li><a href="#int_lifetime_end"><tt>llvm.lifetime.end</tt></a></li>
281 <li><a href="#int_invariant_start"><tt>llvm.invariant.start</tt></a></li>
282 <li><a href="#int_invariant_end"><tt>llvm.invariant.end</tt></a></li>
283 </ol>
284 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]285 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]286 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]287 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]288 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]289 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]290 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]291 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]292 '<tt>llvm.trap</tt>' Intrinsic</a></li>
293 <li><a href="#int_stackprotector">
294 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]295 <li><a href="#int_objectsize">
296 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]297 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]298 </li>
299 </ol>
300 </li>
301</ol>
302
303<div class="doc_author">
304 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
305 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
306</div>
307
308<!-- *********************************************************************** -->
309<div class="doc_section"> <a name="abstract">Abstract </a></div>
310<!-- *********************************************************************** -->
311
312<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]313
314<p>This document is a reference manual for the LLVM assembly language. LLVM is
315 a Static Single Assignment (SSA) based representation that provides type
316 safety, low-level operations, flexibility, and the capability of representing
317 'all' high-level languages cleanly. It is the common code representation
318 used throughout all phases of the LLVM compilation strategy.</p>
319
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]320</div>
321
322<!-- *********************************************************************** -->
323<div class="doc_section"> <a name="introduction">Introduction</a> </div>
324<!-- *********************************************************************** -->
325
326<div class="doc_text">
327
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]328<p>The LLVM code representation is designed to be used in three different forms:
329 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
330 for fast loading by a Just-In-Time compiler), and as a human readable
331 assembly language representation. This allows LLVM to provide a powerful
332 intermediate representation for efficient compiler transformations and
333 analysis, while providing a natural means to debug and visualize the
334 transformations. The three different forms of LLVM are all equivalent. This
335 document describes the human readable representation and notation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]337<p>The LLVM representation aims to be light-weight and low-level while being
338 expressive, typed, and extensible at the same time. It aims to be a
339 "universal IR" of sorts, by being at a low enough level that high-level ideas
340 may be cleanly mapped to it (similar to how microprocessors are "universal
341 IR's", allowing many source languages to be mapped to them). By providing
342 type information, LLVM can be used as the target of optimizations: for
343 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]344 variable is never accessed outside of the current function, allowing it to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]345 be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347</div>
348
349<!-- _______________________________________________________________________ -->
350<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
351
352<div class="doc_text">
353
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]354<p>It is important to note that this document describes 'well formed' LLVM
355 assembly language. There is a difference between what the parser accepts and
356 what is considered 'well formed'. For example, the following instruction is
357 syntactically okay, but not well formed:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]358
359<div class="doc_code">
360<pre>
361%x = <a href="#i_add">add</a> i32 1, %x
362</pre>
363</div>
364
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]365<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
366 LLVM infrastructure provides a verification pass that may be used to verify
367 that an LLVM module is well formed. This pass is automatically run by the
368 parser after parsing input assembly and by the optimizer before it outputs
369 bitcode. The violations pointed out by the verifier pass indicate bugs in
370 transformation passes or input to the parser.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]372</div>
373
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]374<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]375
376<!-- *********************************************************************** -->
377<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
378<!-- *********************************************************************** -->
379
380<div class="doc_text">
381
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]382<p>LLVM identifiers come in two basic types: global and local. Global
383 identifiers (functions, global variables) begin with the <tt>'@'</tt>
384 character. Local identifiers (register names, types) begin with
385 the <tt>'%'</tt> character. Additionally, there are three different formats
386 for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]387
388<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]389 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]390 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
391 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
392 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
393 other characters in their names can be surrounded with quotes. Special
394 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
395 ASCII code for the character in hexadecimal. In this way, any character
396 can be used in a name value, even quotes themselves.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]397
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]398 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]399 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]400
401 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]402 constants</a>, below.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]403</ol>
404
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]405<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]406 don't need to worry about name clashes with reserved words, and the set of
407 reserved words may be expanded in the future without penalty. Additionally,
408 unnamed identifiers allow a compiler to quickly come up with a temporary
409 variable without having to avoid symbol table conflicts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]410
411<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]412 languages. There are keywords for different opcodes
413 ('<tt><a href="#i_add">add</a></tt>',
414 '<tt><a href="#i_bitcast">bitcast</a></tt>',
415 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
416 ('<tt><a href="#t_void">void</a></tt>',
417 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
418 reserved words cannot conflict with variable names, because none of them
419 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]420
421<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]422 '<tt>%X</tt>' by 8:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]423
424<p>The easy way:</p>
425
426<div class="doc_code">
427<pre>
428%result = <a href="#i_mul">mul</a> i32 %X, 8
429</pre>
430</div>
431
432<p>After strength reduction:</p>
433
434<div class="doc_code">
435<pre>
436%result = <a href="#i_shl">shl</a> i32 %X, i8 3
437</pre>
438</div>
439
440<p>And the hard way:</p>
441
442<div class="doc_code">
443<pre>
Gabor Greifc0ea7672009-10-28 13:05:07 +0000[diff] [blame]444%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
445%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]446%result = <a href="#i_add">add</a> i32 %1, %1
447</pre>
448</div>
449
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]450<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
451 lexical features of LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]452
453<ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]454 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]455 line.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]456
457 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]458 assigned to a named value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]459
460 <li>Unnamed temporaries are numbered sequentially</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]461</ol>
462
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]463<p>It also shows a convention that we follow in this document. When
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]464 demonstrating instructions, we will follow an instruction with a comment that
465 defines the type and name of value produced. Comments are shown in italic
466 text.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]467
468</div>
469
470<!-- *********************************************************************** -->
471<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
472<!-- *********************************************************************** -->
473
474<!-- ======================================================================= -->
475<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
476</div>
477
478<div class="doc_text">
479
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]480<p>LLVM programs are composed of "Module"s, each of which is a translation unit
481 of the input programs. Each module consists of functions, global variables,
482 and symbol table entries. Modules may be combined together with the LLVM
483 linker, which merges function (and global variable) definitions, resolves
484 forward declarations, and merges symbol table entries. Here is an example of
485 the "hello world" module:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]486
487<div class="doc_code">
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]488<pre>
489<i>; Declare the string constant as a global constant.</i>
490<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]491
492<i>; External declaration of the puts function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]493<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]494
495<i>; Definition of main function</i>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]496define i32 @main() { <i>; i32()* </i>
497 <i>; Convert [13 x i8]* to i8 *...</i>
498 %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]499
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]500 <i>; Call puts function to write out the string to stdout.</i>
501 <a href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]502 <a href="#i_ret">ret</a> i32 0<br>}
503
504<i>; Named metadata</i>
505!1 = metadata !{i32 41}
506!foo = !{!1, null}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507</pre>
508</div>
509
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]510<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]511 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]512 a <a href="#functionstructure">function definition</a> for
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]513 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
514 "<tt>foo"</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]515
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]516<p>In general, a module is made up of a list of global values, where both
517 functions and global variables are global values. Global values are
518 represented by a pointer to a memory location (in this case, a pointer to an
519 array of char, and a pointer to a function), and have one of the
520 following <a href="#linkage">linkage types</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]521
522</div>
523
524<!-- ======================================================================= -->
525<div class="doc_subsection">
526 <a name="linkage">Linkage Types</a>
527</div>
528
529<div class="doc_text">
530
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]531<p>All Global Variables and Functions have one of the following types of
532 linkage:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]533
534<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]535 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]536 <dd>Global values with private linkage are only directly accessible by objects
537 in the current module. In particular, linking code into a module with an
538 private global value may cause the private to be renamed as necessary to
539 avoid collisions. Because the symbol is private to the module, all
540 references can be updated. This doesn't show up in any symbol table in the
541 object file.</dd>
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]542
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]544 <dd>Similar to private, but the symbol is passed through the assembler and
Chris Lattner06c1ecc2009-08-24 04:32:16 +0000[diff] [blame]545 removed by the linker after evaluation. Note that (unlike private
546 symbols) linker_private symbols are subject to coalescing by the linker:
547 weak symbols get merged and redefinitions are rejected. However, unlike
548 normal strong symbols, they are removed by the linker from the final
549 linked image (executable or dynamic library).</dd>
Bill Wendling41a07852009-07-20 01:03:30 +0000[diff] [blame]550
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]551 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]552 <dd>Similar to private, but the value shows as a local symbol
553 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
554 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]555
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]556 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]557 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]558 into the object file corresponding to the LLVM module. They exist to
559 allow inlining and other optimizations to take place given knowledge of
560 the definition of the global, which is known to be somewhere outside the
561 module. Globals with <tt>available_externally</tt> linkage are allowed to
562 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
563 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]564
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]565 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]566 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattnerd16c5512010-01-09 19:15:14 +0000[diff] [blame]567 the same name when linkage occurs. This can be used to implement
568 some forms of inline functions, templates, or other code which must be
569 generated in each translation unit that uses it, but where the body may
570 be overridden with a more definitive definition later. Unreferenced
571 <tt>linkonce</tt> globals are allowed to be discarded. Note that
572 <tt>linkonce</tt> linkage does not actually allow the optimizer to
573 inline the body of this function into callers because it doesn't know if
574 this definition of the function is the definitive definition within the
575 program or whether it will be overridden by a stronger definition.
576 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
577 linkage.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]579 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]580 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
581 <tt>linkonce</tt> linkage, except that unreferenced globals with
582 <tt>weak</tt> linkage may not be discarded. This is used for globals that
583 are declared "weak" in C source code.</dd>
584
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]585 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]586 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
587 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
588 global scope.
589 Symbols with "<tt>common</tt>" linkage are merged in the same way as
590 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]591 <tt>common</tt> symbols may not have an explicit section,
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]592 must have a zero initializer, and may not be marked '<a
Chris Lattner83c4a712009-08-05 05:41:44 +0000[diff] [blame]593 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
594 have common linkage.</dd>
Chris Lattner7215c7f2009-08-05 05:21:07 +0000[diff] [blame]595
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]596
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]597 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]598 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]599 pointer to array type. When two global variables with appending linkage
600 are linked together, the two global arrays are appended together. This is
601 the LLVM, typesafe, equivalent of having the system linker append together
602 "sections" with identical names when .o files are linked.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]603
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]604 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]605 <dd>The semantics of this linkage follow the ELF object file model: the symbol
606 is weak until linked, if not linked, the symbol becomes null instead of
607 being an undefined reference.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]608
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
610 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]611 <dd>Some languages allow differing globals to be merged, such as two functions
612 with different semantics. Other languages, such as <tt>C++</tt>, ensure
613 that only equivalent globals are ever merged (the "one definition rule" -
614 "ODR"). Such languages can use the <tt>linkonce_odr</tt>
615 and <tt>weak_odr</tt> linkage types to indicate that the global will only
616 be merged with equivalent globals. These linkage types are otherwise the
617 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]618
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]619 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]620 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]621 visible, meaning that it participates in linkage and can be used to
622 resolve external symbol references.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623</dl>
624
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]625<p>The next two types of linkage are targeted for Microsoft Windows platform
626 only. They are designed to support importing (exporting) symbols from (to)
627 DLLs (Dynamic Link Libraries).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]628
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]629<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]630 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]631 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]632 or variable via a global pointer to a pointer that is set up by the DLL
633 exporting the symbol. On Microsoft Windows targets, the pointer name is
634 formed by combining <code>__imp_</code> and the function or variable
635 name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]636
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]637 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]638 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]639 pointer to a pointer in a DLL, so that it can be referenced with the
640 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
641 name is formed by combining <code>__imp_</code> and the function or
642 variable name.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]643</dl>
644
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]645<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
646 another module defined a "<tt>.LC0</tt>" variable and was linked with this
647 one, one of the two would be renamed, preventing a collision. Since
648 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
649 declarations), they are accessible outside of the current module.</p>
650
651<p>It is illegal for a function <i>declaration</i> to have any linkage type
652 other than "externally visible", <tt>dllimport</tt>
653 or <tt>extern_weak</tt>.</p>
654
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]655<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]656 or <tt>weak_odr</tt> linkages.</p>
657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658</div>
659
660<!-- ======================================================================= -->
661<div class="doc_subsection">
662 <a name="callingconv">Calling Conventions</a>
663</div>
664
665<div class="doc_text">
666
667<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]668 and <a href="#i_invoke">invokes</a> can all have an optional calling
669 convention specified for the call. The calling convention of any pair of
670 dynamic caller/callee must match, or the behavior of the program is
671 undefined. The following calling conventions are supported by LLVM, and more
672 may be added in the future:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]673
674<dl>
675 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]676 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]677 specified) matches the target C calling conventions. This calling
678 convention supports varargs function calls and tolerates some mismatch in
679 the declared prototype and implemented declaration of the function (as
680 does normal C).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]681
682 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]683 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]684 (e.g. by passing things in registers). This calling convention allows the
685 target to use whatever tricks it wants to produce fast code for the
686 target, without having to conform to an externally specified ABI
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]687 (Application Binary Interface).
688 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
689 when this convention is used.</a> This calling convention does not
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]690 support varargs and requires the prototype of all callees to exactly match
691 the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]692
693 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]694 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]695 as possible under the assumption that the call is not commonly executed.
696 As such, these calls often preserve all registers so that the call does
697 not break any live ranges in the caller side. This calling convention
698 does not support varargs and requires the prototype of all callees to
699 exactly match the prototype of the function definition.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700
701 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]702 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]703 target-specific calling conventions to be used. Target specific calling
704 conventions start at 64.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]705</dl>
706
707<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]708 support Pascal conventions or any other well-known target-independent
709 convention.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]710
711</div>
712
713<!-- ======================================================================= -->
714<div class="doc_subsection">
715 <a name="visibility">Visibility Styles</a>
716</div>
717
718<div class="doc_text">
719
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]720<p>All Global Variables and Functions have one of the following visibility
721 styles:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]722
723<dl>
724 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]725 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]726 that the declaration is visible to other modules and, in shared libraries,
727 means that the declared entity may be overridden. On Darwin, default
728 visibility means that the declaration is visible to other modules. Default
729 visibility corresponds to "external linkage" in the language.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]730
731 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]732 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]733 object if they are in the same shared object. Usually, hidden visibility
734 indicates that the symbol will not be placed into the dynamic symbol
735 table, so no other module (executable or shared library) can reference it
736 directly.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737
738 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]739 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]740 the dynamic symbol table, but that references within the defining module
741 will bind to the local symbol. That is, the symbol cannot be overridden by
742 another module.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]743</dl>
744
745</div>
746
747<!-- ======================================================================= -->
748<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]749 <a name="namedtypes">Named Types</a>
750</div>
751
752<div class="doc_text">
753
754<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]755 it easier to read the IR and make the IR more condensed (particularly when
756 recursive types are involved). An example of a name specification is:</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]757
758<div class="doc_code">
759<pre>
760%mytype = type { %mytype*, i32 }
761</pre>
762</div>
763
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]764<p>You may give a name to any <a href="#typesystem">type</a> except
765 "<a href="t_void">void</a>". Type name aliases may be used anywhere a type
766 is expected with the syntax "%mytype".</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]767
768<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]769 and that you can therefore specify multiple names for the same type. This
770 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
771 uses structural typing, the name is not part of the type. When printing out
772 LLVM IR, the printer will pick <em>one name</em> to render all types of a
773 particular shape. This means that if you have code where two different
774 source types end up having the same LLVM type, that the dumper will sometimes
775 print the "wrong" or unexpected type. This is an important design point and
776 isn't going to change.</p>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]777
778</div>
779
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]780<!-- ======================================================================= -->
781<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]782 <a name="globalvars">Global Variables</a>
783</div>
784
785<div class="doc_text">
786
787<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]788 instead of run-time. Global variables may optionally be initialized, may
789 have an explicit section to be placed in, and may have an optional explicit
790 alignment specified. A variable may be defined as "thread_local", which
791 means that it will not be shared by threads (each thread will have a
792 separated copy of the variable). A variable may be defined as a global
793 "constant," which indicates that the contents of the variable
794 will <b>never</b> be modified (enabling better optimization, allowing the
795 global data to be placed in the read-only section of an executable, etc).
796 Note that variables that need runtime initialization cannot be marked
797 "constant" as there is a store to the variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]798
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]799<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
800 constant, even if the final definition of the global is not. This capability
801 can be used to enable slightly better optimization of the program, but
802 requires the language definition to guarantee that optimizations based on the
803 'constantness' are valid for the translation units that do not include the
804 definition.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]805
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]806<p>As SSA values, global variables define pointer values that are in scope
807 (i.e. they dominate) all basic blocks in the program. Global variables
808 always define a pointer to their "content" type because they describe a
809 region of memory, and all memory objects in LLVM are accessed through
810 pointers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]812<p>A global variable may be declared to reside in a target-specific numbered
813 address space. For targets that support them, address spaces may affect how
814 optimizations are performed and/or what target instructions are used to
815 access the variable. The default address space is zero. The address space
816 qualifier must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]817
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]818<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]819 supports it, it will emit globals to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]820
821<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]822 the alignment is set to zero, the alignment of the global is set by the
823 target to whatever it feels convenient. If an explicit alignment is
824 specified, the global is forced to have at least that much alignment. All
825 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]826
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]827<p>For example, the following defines a global in a numbered address space with
828 an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]829
830<div class="doc_code">
831<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]832@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]833</pre>
834</div>
835
836</div>
837
838
839<!-- ======================================================================= -->
840<div class="doc_subsection">
841 <a name="functionstructure">Functions</a>
842</div>
843
844<div class="doc_text">
845
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]846<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
847 optional <a href="#linkage">linkage type</a>, an optional
848 <a href="#visibility">visibility style</a>, an optional
849 <a href="#callingconv">calling convention</a>, a return type, an optional
850 <a href="#paramattrs">parameter attribute</a> for the return type, a function
851 name, a (possibly empty) argument list (each with optional
852 <a href="#paramattrs">parameter attributes</a>), optional
853 <a href="#fnattrs">function attributes</a>, an optional section, an optional
854 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
855 curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]857<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
858 optional <a href="#linkage">linkage type</a>, an optional
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]859 <a href="#visibility">visibility style</a>, an optional
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]860 <a href="#callingconv">calling convention</a>, a return type, an optional
861 <a href="#paramattrs">parameter attribute</a> for the return type, a function
862 name, a possibly empty list of arguments, an optional alignment, and an
863 optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]864
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]865<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]866 (Control Flow Graph) for the function. Each basic block may optionally start
867 with a label (giving the basic block a symbol table entry), contains a list
868 of instructions, and ends with a <a href="#terminators">terminator</a>
869 instruction (such as a branch or function return).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]870
871<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]872 executed on entrance to the function, and it is not allowed to have
873 predecessor basic blocks (i.e. there can not be any branches to the entry
874 block of a function). Because the block can have no predecessors, it also
875 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]876
877<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]878 supports it, it will emit functions to the section specified.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]879
880<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]881 the alignment is set to zero, the alignment of the function is set by the
882 target to whatever it feels convenient. If an explicit alignment is
883 specified, the function is forced to have at least that much alignment. All
884 alignments must be a power of 2.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]885
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]886<h5>Syntax:</h5>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]887<div class="doc_code">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]888<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]889define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]890 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
891 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
892 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
893 [<a href="#gc">gc</a>] { ... }
894</pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]895</div>
896
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]897</div>
898
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]899<!-- ======================================================================= -->
900<div class="doc_subsection">
901 <a name="aliasstructure">Aliases</a>
902</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]904<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]905
906<p>Aliases act as "second name" for the aliasee value (which can be either
907 function, global variable, another alias or bitcast of global value). Aliases
908 may have an optional <a href="#linkage">linkage type</a>, and an
909 optional <a href="#visibility">visibility style</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]910
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]911<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]912<div class="doc_code">
913<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]914@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915</pre>
916</div>
917
918</div>
919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]920<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]921<div class="doc_subsection">
922 <a name="namedmetadatastructure">Named Metadata</a>
923</div>
924
925<div class="doc_text">
926
927<p>Named metadata is a collection of metadata. <a href="#metadata"> Metadata </a>
928 node and null are the only valid named metadata operands.
929 Metadata strings are not allowed as an named metadata operand.</p>
930
931<h5>Syntax:</h5>
932<div class="doc_code">
933<pre>
934!1 = metadata !{metadata !"one"}
935!name = !{null, !1}
936</pre>
937</div>
938
939</div>
940
941<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]942<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]943
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]944<div class="doc_text">
945
946<p>The return type and each parameter of a function type may have a set of
947 <i>parameter attributes</i> associated with them. Parameter attributes are
948 used to communicate additional information about the result or parameters of
949 a function. Parameter attributes are considered to be part of the function,
950 not of the function type, so functions with different parameter attributes
951 can have the same function type.</p>
952
953<p>Parameter attributes are simple keywords that follow the type specified. If
954 multiple parameter attributes are needed, they are space separated. For
955 example:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]956
957<div class="doc_code">
958<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]959declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]960declare i32 @atoi(i8 zeroext)
961declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]962</pre>
963</div>
964
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]965<p>Note that any attributes for the function result (<tt>nounwind</tt>,
966 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]967
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]968<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]969
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]970<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]971 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]972 <dd>This indicates to the code generator that the parameter or return value
973 should be zero-extended to a 32-bit value by the caller (for a parameter)
974 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]975
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]976 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]977 <dd>This indicates to the code generator that the parameter or return value
978 should be sign-extended to a 32-bit value by the caller (for a parameter)
979 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]980
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]981 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]982 <dd>This indicates that this parameter or return value should be treated in a
983 special target-dependent fashion during while emitting code for a function
984 call or return (usually, by putting it in a register as opposed to memory,
985 though some targets use it to distinguish between two different kinds of
986 registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]987
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]988 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]989 <dd>This indicates that the pointer parameter should really be passed by value
990 to the function. The attribute implies that a hidden copy of the pointee
991 is made between the caller and the callee, so the callee is unable to
992 modify the value in the callee. This attribute is only valid on LLVM
993 pointer arguments. It is generally used to pass structs and arrays by
994 value, but is also valid on pointers to scalars. The copy is considered
995 to belong to the caller not the callee (for example,
996 <tt><a href="#readonly">readonly</a></tt> functions should not write to
997 <tt>byval</tt> parameters). This is not a valid attribute for return
998 values. The byval attribute also supports specifying an alignment with
999 the align attribute. This has a target-specific effect on the code
1000 generator that usually indicates a desired alignment for the synthesized
1001 stack slot.</dd>
1002
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1003 <dt><tt><b>sret</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1004 <dd>This indicates that the pointer parameter specifies the address of a
1005 structure that is the return value of the function in the source program.
1006 This pointer must be guaranteed by the caller to be valid: loads and
1007 stores to the structure may be assumed by the callee to not to trap. This
1008 may only be applied to the first parameter. This is not a valid attribute
1009 for return values. </dd>
1010
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1011 <dt><tt><b>noalias</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1012 <dd>This indicates that the pointer does not alias any global or any other
1013 parameter. The caller is responsible for ensuring that this is the
1014 case. On a function return value, <tt>noalias</tt> additionally indicates
1015 that the pointer does not alias any other pointers visible to the
1016 caller. For further details, please see the discussion of the NoAlias
1017 response in
1018 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
1019 analysis</a>.</dd>
1020
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1021 <dt><tt><b>nocapture</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1022 <dd>This indicates that the callee does not make any copies of the pointer
1023 that outlive the callee itself. This is not a valid attribute for return
1024 values.</dd>
1025
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1026 <dt><tt><b>nest</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1027 <dd>This indicates that the pointer parameter can be excised using the
1028 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1029 attribute for return values.</dd>
1030</dl>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1031
1032</div>
1033
1034<!-- ======================================================================= -->
1035<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1036 <a name="gc">Garbage Collector Names</a>
1037</div>
1038
1039<div class="doc_text">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1040
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1041<p>Each function may specify a garbage collector name, which is simply a
1042 string:</p>
1043
1044<div class="doc_code">
1045<pre>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1046define void @f() gc "name" { ... }
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1047</pre>
1048</div>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1049
1050<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1051 collector which will cause the compiler to alter its output in order to
1052 support the named garbage collection algorithm.</p>
1053
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1054</div>
1055
1056<!-- ======================================================================= -->
1057<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1058 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1059</div>
1060
1061<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1062
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1063<p>Function attributes are set to communicate additional information about a
1064 function. Function attributes are considered to be part of the function, not
1065 of the function type, so functions with different parameter attributes can
1066 have the same function type.</p>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1067
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1068<p>Function attributes are simple keywords that follow the type specified. If
1069 multiple attributes are needed, they are space separated. For example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1070
1071<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1072<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1073define void @f() noinline { ... }
1074define void @f() alwaysinline { ... }
1075define void @f() alwaysinline optsize { ... }
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1076define void @f() optsize { ... }
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1077</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1078</div>
1079
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1080<dl>
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1081 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1082 <dd>This attribute indicates that the inliner should attempt to inline this
1083 function into callers whenever possible, ignoring any active inlining size
1084 threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1085
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1086 <dt><tt><b>inlinehint</b></tt></dt>
Dale Johannesen7fd6b0f2009-08-26 01:08:21 +0000[diff] [blame]1087 <dd>This attribute indicates that the source code contained a hint that inlining
1088 this function is desirable (such as the "inline" keyword in C/C++). It
1089 is just a hint; it imposes no requirements on the inliner.</dd>
1090
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1091 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1092 <dd>This attribute indicates that the inliner should never inline this
1093 function in any situation. This attribute may not be used together with
1094 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1095
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1096 <dt><tt><b>optsize</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1097 <dd>This attribute suggests that optimization passes and code generator passes
1098 make choices that keep the code size of this function low, and otherwise
1099 do optimizations specifically to reduce code size.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1100
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1101 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1102 <dd>This function attribute indicates that the function never returns
1103 normally. This produces undefined behavior at runtime if the function
1104 ever does dynamically return.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1105
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1106 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1107 <dd>This function attribute indicates that the function never returns with an
1108 unwind or exceptional control flow. If the function does unwind, its
1109 runtime behavior is undefined.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1110
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1111 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1112 <dd>This attribute indicates that the function computes its result (or decides
1113 to unwind an exception) based strictly on its arguments, without
1114 dereferencing any pointer arguments or otherwise accessing any mutable
1115 state (e.g. memory, control registers, etc) visible to caller functions.
1116 It does not write through any pointer arguments
1117 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1118 changes any state visible to callers. This means that it cannot unwind
1119 exceptions by calling the <tt>C++</tt> exception throwing methods, but
1120 could use the <tt>unwind</tt> instruction.</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1121
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1122 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1123 <dd>This attribute indicates that the function does not write through any
1124 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1125 arguments) or otherwise modify any state (e.g. memory, control registers,
1126 etc) visible to caller functions. It may dereference pointer arguments
1127 and read state that may be set in the caller. A readonly function always
1128 returns the same value (or unwinds an exception identically) when called
1129 with the same set of arguments and global state. It cannot unwind an
1130 exception by calling the <tt>C++</tt> exception throwing methods, but may
1131 use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame]1132
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1133 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1134 <dd>This attribute indicates that the function should emit a stack smashing
1135 protector. It is in the form of a "canary"&mdash;a random value placed on
1136 the stack before the local variables that's checked upon return from the
1137 function to see if it has been overwritten. A heuristic is used to
1138 determine if a function needs stack protectors or not.<br>
1139<br>
1140 If a function that has an <tt>ssp</tt> attribute is inlined into a
1141 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1142 function will have an <tt>ssp</tt> attribute.</dd>
1143
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1144 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1145 <dd>This attribute indicates that the function should <em>always</em> emit a
1146 stack smashing protector. This overrides
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1147 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1148<br>
1149 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1150 function that doesn't have an <tt>sspreq</tt> attribute or which has
1151 an <tt>ssp</tt> attribute, then the resulting function will have
1152 an <tt>sspreq</tt> attribute.</dd>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1153
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1154 <dt><tt><b>noredzone</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1155 <dd>This attribute indicates that the code generator should not use a red
1156 zone, even if the target-specific ABI normally permits it.</dd>
1157
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b>noimplicitfloat</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attributes disables implicit floating point instructions.</dd>
1160
Bill Wendling614b32b2009-11-02 00:24:16 +0000[diff] [blame]1161 <dt><tt><b>naked</b></tt></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1162 <dd>This attribute disables prologue / epilogue emission for the function.
1163 This can have very system-specific consequences.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1164</dl>
1165
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1166</div>
1167
1168<!-- ======================================================================= -->
1169<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1170 <a name="moduleasm">Module-Level Inline Assembly</a>
1171</div>
1172
1173<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1174
1175<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1176 the GCC "file scope inline asm" blocks. These blocks are internally
1177 concatenated by LLVM and treated as a single unit, but may be separated in
1178 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1179
1180<div class="doc_code">
1181<pre>
1182module asm "inline asm code goes here"
1183module asm "more can go here"
1184</pre>
1185</div>
1186
1187<p>The strings can contain any character by escaping non-printable characters.
1188 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]1189 for the number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1190
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1191<p>The inline asm code is simply printed to the machine code .s file when
1192 assembly code is generated.</p>
1193
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1194</div>
1195
1196<!-- ======================================================================= -->
1197<div class="doc_subsection">
1198 <a name="datalayout">Data Layout</a>
1199</div>
1200
1201<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1202
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1203<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1204 data is to be laid out in memory. The syntax for the data layout is
1205 simply:</p>
1206
1207<div class="doc_code">
1208<pre>
1209target datalayout = "<i>layout specification</i>"
1210</pre>
1211</div>
1212
1213<p>The <i>layout specification</i> consists of a list of specifications
1214 separated by the minus sign character ('-'). Each specification starts with
1215 a letter and may include other information after the letter to define some
1216 aspect of the data layout. The specifications accepted are as follows:</p>
1217
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1218<dl>
1219 <dt><tt>E</tt></dt>
1220 <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]1221 bits with the most significance have the lowest address location.</dd>
1222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1223 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1224 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1225 the bits with the least significance have the lowest address
1226 location.</dd>
1227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1229 <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]1230 <i>preferred</i> alignments. All sizes are in bits. Specifying
1231 the <i>pref</i> alignment is optional. If omitted, the
1232 preceding <tt>:</tt> should be omitted too.</dd>
1233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1234 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1235 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1236 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1238 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1239 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1240 <i>size</i>.</dd>
1241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1242 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1243 <dd>This specifies the alignment for a floating point type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1244 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1245 (double).</dd>
1246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1247 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1248 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1249 <i>size</i>.</dd>
1250
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1251 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1252 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1253 <i>size</i>.</dd>
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1254
1255 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1256 <dd>This specifies a set of native integer widths for the target CPU
1257 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1258 "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]1259 this set are considered to support most general arithmetic
Chris Lattnerece41802009-11-07 09:35:34 +0000[diff] [blame]1260 operations efficiently.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1261</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1262
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1263<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1264 default set of specifications which are then (possibly) overriden by the
1265 specifications in the <tt>datalayout</tt> keyword. The default specifications
1266 are given in this list:</p>
1267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1268<ul>
1269 <li><tt>E</tt> - big endian</li>
1270 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1271 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1272 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1273 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1274 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1275 <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]1276 alignment of 64-bits</li>
1277 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1278 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1279 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1280 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1281 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1282 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1283</ul>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1284
1285<p>When LLVM is determining the alignment for a given type, it uses the
1286 following rules:</p>
1287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1288<ol>
1289 <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]1290 specification is used.</li>
1291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1292 <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]1293 smallest integer type that is larger than the bitwidth of the sought type
1294 is used. If none of the specifications are larger than the bitwidth then
1295 the the largest integer type is used. For example, given the default
1296 specifications above, the i7 type will use the alignment of i8 (next
1297 largest) while both i65 and i256 will use the alignment of i64 (largest
1298 specified).</li>
1299
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1300 <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]1301 largest vector type that is smaller than the sought vector type will be
1302 used as a fall back. This happens because &lt;128 x double&gt; can be
1303 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1304</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1306</div>
1307
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1308<!-- ======================================================================= -->
1309<div class="doc_subsection">
1310 <a name="pointeraliasing">Pointer Aliasing Rules</a>
1311</div>
1312
1313<div class="doc_text">
1314
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1315<p>Any memory access must be done through a pointer value associated
Andreas Bolka23bece42009-07-27 20:37:10 +0000[diff] [blame]1316with an address range of the memory access, otherwise the behavior
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1317is undefined. Pointer values are associated with address ranges
1318according to the following rules:</p>
1319
1320<ul>
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1321 <li>A pointer value formed from a
1322 <tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
1323 is associated with the addresses associated with the first operand
1324 of the <tt>getelementptr</tt>.</li>
1325 <li>An address of a global variable is associated with the address
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1326 range of the variable's storage.</li>
1327 <li>The result value of an allocation instruction is associated with
1328 the address range of the allocated storage.</li>
1329 <li>A null pointer in the default address-space is associated with
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1330 no address.</li>
1331 <li>A pointer value formed by an
1332 <tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
1333 address ranges of all pointer values that contribute (directly or
1334 indirectly) to the computation of the pointer's value.</li>
1335 <li>The result value of a
1336 <tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1337 addresses associated with the operand of the <tt>bitcast</tt>.</li>
1338 <li>An integer constant other than zero or a pointer value returned
1339 from a function not defined within LLVM may be associated with address
1340 ranges allocated through mechanisms other than those provided by
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1341 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1342 allocated by mechanisms provided by LLVM.</li>
1343 </ul>
1344
1345<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka11fbf432009-07-29 00:02:05 +0000[diff] [blame]1346<tt><a href="#i_load">load</a></tt> merely indicates the size and
1347alignment of the memory from which to load, as well as the
1348interpretation of the value. The first operand of a
1349<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1350and alignment of the store.</p>
Dan Gohman27b47012009-07-27 18:07:55 +0000[diff] [blame]1351
1352<p>Consequently, type-based alias analysis, aka TBAA, aka
1353<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1354LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1355additional information which specialized optimization passes may use
1356to implement type-based alias analysis.</p>
1357
1358</div>
1359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1360<!-- *********************************************************************** -->
1361<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1362<!-- *********************************************************************** -->
1363
1364<div class="doc_text">
1365
1366<p>The LLVM type system is one of the most important features of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1367 intermediate representation. Being typed enables a number of optimizations
1368 to be performed on the intermediate representation directly, without having
1369 to do extra analyses on the side before the transformation. A strong type
1370 system makes it easier to read the generated code and enables novel analyses
1371 and transformations that are not feasible to perform on normal three address
1372 code representations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1373
1374</div>
1375
1376<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1377<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378Classifications</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1380<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1381
1382<p>The types fall into a few useful classifications:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1383
1384<table border="1" cellspacing="0" cellpadding="4">
1385 <tbody>
1386 <tr><th>Classification</th><th>Types</th></tr>
1387 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1388 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1389 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1390 </tr>
1391 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1392 <td><a href="#t_floating">floating point</a></td>
1393 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1394 </tr>
1395 <tr>
1396 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1397 <td><a href="#t_integer">integer</a>,
1398 <a href="#t_floating">floating point</a>,
1399 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1400 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1401 <a href="#t_struct">structure</a>,
1402 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1403 <a href="#t_label">label</a>,
1404 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1405 </td>
1406 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1407 <tr>
1408 <td><a href="#t_primitive">primitive</a></td>
1409 <td><a href="#t_label">label</a>,
1410 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1411 <a href="#t_floating">floating point</a>,
1412 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1413 </tr>
1414 <tr>
1415 <td><a href="#t_derived">derived</a></td>
1416 <td><a href="#t_integer">integer</a>,
1417 <a href="#t_array">array</a>,
1418 <a href="#t_function">function</a>,
1419 <a href="#t_pointer">pointer</a>,
1420 <a href="#t_struct">structure</a>,
1421 <a href="#t_pstruct">packed structure</a>,
1422 <a href="#t_vector">vector</a>,
1423 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1424 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1425 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1426 </tbody>
1427</table>
1428
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1429<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1430 important. Values of these types are the only ones which can be produced by
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1431 instructions.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1433</div>
1434
1435<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1436<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1437
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1438<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1439
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1440<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1441 system.</p>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1442
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1443</div>
1444
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1445<!-- _______________________________________________________________________ -->
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1446<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1447
1448<div class="doc_text">
1449
1450<h5>Overview:</h5>
1451<p>The integer type is a very simple type that simply specifies an arbitrary
1452 bit width for the integer type desired. Any bit width from 1 bit to
1453 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1454
1455<h5>Syntax:</h5>
1456<pre>
1457 iN
1458</pre>
1459
1460<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1461 value.</p>
1462
1463<h5>Examples:</h5>
1464<table class="layout">
1465 <tr class="layout">
1466 <td class="left"><tt>i1</tt></td>
1467 <td class="left">a single-bit integer.</td>
1468 </tr>
1469 <tr class="layout">
1470 <td class="left"><tt>i32</tt></td>
1471 <td class="left">a 32-bit integer.</td>
1472 </tr>
1473 <tr class="layout">
1474 <td class="left"><tt>i1942652</tt></td>
1475 <td class="left">a really big integer of over 1 million bits.</td>
1476 </tr>
1477</table>
1478
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1479</div>
1480
1481<!-- _______________________________________________________________________ -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1482<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1483
1484<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1485
1486<table>
1487 <tbody>
1488 <tr><th>Type</th><th>Description</th></tr>
1489 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1490 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1491 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1492 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1493 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1494 </tbody>
1495</table>
1496
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1497</div>
1498
1499<!-- _______________________________________________________________________ -->
1500<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1501
1502<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1503
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1504<h5>Overview:</h5>
1505<p>The void type does not represent any value and has no size.</p>
1506
1507<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1508<pre>
1509 void
1510</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1511
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1512</div>
1513
1514<!-- _______________________________________________________________________ -->
1515<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1516
1517<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1518
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1519<h5>Overview:</h5>
1520<p>The label type represents code labels.</p>
1521
1522<h5>Syntax:</h5>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1523<pre>
1524 label
1525</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1526
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1527</div>
1528
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1529<!-- _______________________________________________________________________ -->
1530<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1531
1532<div class="doc_text">
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1533
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1534<h5>Overview:</h5>
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1535<p>The metadata type represents embedded metadata. No derived types may be
1536 created from metadata except for <a href="#t_function">function</a>
1537 arguments.
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1538
1539<h5>Syntax:</h5>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1540<pre>
1541 metadata
1542</pre>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1543
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1544</div>
1545
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1546
1547<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1548<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1549
1550<div class="doc_text">
1551
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1552<p>The real power in LLVM comes from the derived types in the system. This is
1553 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1554 useful types. Each of these types contain one or more element types which
1555 may be a primitive type, or another derived type. For example, it is
1556 possible to have a two dimensional array, using an array as the element type
1557 of another array.</p>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1558
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1559</div>
1560
1561<!-- _______________________________________________________________________ -->
1562<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1563
1564<div class="doc_text">
1565
1566<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1567<p>The array type is a very simple derived type that arranges elements
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1568 sequentially in memory. The array type requires a size (number of elements)
1569 and an underlying data type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1570
1571<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1572<pre>
1573 [&lt;# elements&gt; x &lt;elementtype&gt;]
1574</pre>
1575
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1576<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1577 be any type with a size.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1578
1579<h5>Examples:</h5>
1580<table class="layout">
1581 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1582 <td class="left"><tt>[40 x i32]</tt></td>
1583 <td class="left">Array of 40 32-bit integer values.</td>
1584 </tr>
1585 <tr class="layout">
1586 <td class="left"><tt>[41 x i32]</tt></td>
1587 <td class="left">Array of 41 32-bit integer values.</td>
1588 </tr>
1589 <tr class="layout">
1590 <td class="left"><tt>[4 x i8]</tt></td>
1591 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1592 </tr>
1593</table>
1594<p>Here are some examples of multidimensional arrays:</p>
1595<table class="layout">
1596 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1597 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1598 <td class="left">3x4 array of 32-bit integer values.</td>
1599 </tr>
1600 <tr class="layout">
1601 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1602 <td class="left">12x10 array of single precision floating point values.</td>
1603 </tr>
1604 <tr class="layout">
1605 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1606 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1607 </tr>
1608</table>
1609
Dan Gohman87ec5ad2009-11-09 19:01:53 +0000[diff] [blame]1610<p>There is no restriction on indexing beyond the end of the array implied by
1611 a static type (though there are restrictions on indexing beyond the bounds
1612 of an allocated object in some cases). This means that single-dimension
1613 'variable sized array' addressing can be implemented in LLVM with a zero
1614 length array type. An implementation of 'pascal style arrays' in LLVM could
1615 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1616
1617</div>
1618
1619<!-- _______________________________________________________________________ -->
1620<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1621
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1622<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1624<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1625<p>The function type can be thought of as a function signature. It consists of
1626 a return type and a list of formal parameter types. The return type of a
1627 function type is a scalar type, a void type, or a struct type. If the return
1628 type is a struct type then all struct elements must be of first class types,
1629 and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1630
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1631<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1632<pre>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1633 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1634</pre>
1635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1636<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]1637 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1638 which indicates that the function takes a variable number of arguments.
1639 Variable argument functions can access their arguments with
1640 the <a href="#int_varargs">variable argument handling intrinsic</a>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1641 functions. '<tt>&lt;returntype&gt;</tt>' is a any type except
Nick Lewyckyeb021882009-09-27 23:27:42 +0000[diff] [blame]1642 <a href="#t_label">label</a>.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1644<h5>Examples:</h5>
1645<table class="layout">
1646 <tr class="layout">
1647 <td class="left"><tt>i32 (i32)</tt></td>
1648 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1649 </td>
1650 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1651 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1652 </tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1653 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1654 an <tt>i16</tt> that should be sign extended and a
1655 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1656 <tt>float</tt>.
1657 </td>
1658 </tr><tr class="layout">
1659 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]1660 <td class="left">A vararg function that takes at least one
1661 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1662 which returns an integer. This is the signature for <tt>printf</tt> in
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1663 LLVM.
1664 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1665 </tr><tr class="layout">
1666 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky3b3b54d2009-09-27 07:55:32 +0000[diff] [blame]1667 <td class="left">A function taking an <tt>i32</tt>, returning a
1668 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1669 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1670 </tr>
1671</table>
1672
1673</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1674
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1675<!-- _______________________________________________________________________ -->
1676<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1678<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1680<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1681<p>The structure type is used to represent a collection of data members together
1682 in memory. The packing of the field types is defined to match the ABI of the
1683 underlying processor. The elements of a structure may be any type that has a
1684 size.</p>
1685
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]1686<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
1687 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
1688 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
1689 Structures in registers are accessed using the
1690 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
1691 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1692<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1693<pre>
1694 { &lt;type list&gt; }
1695</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1697<h5>Examples:</h5>
1698<table class="layout">
1699 <tr class="layout">
1700 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1701 <td class="left">A triple of three <tt>i32</tt> values</td>
1702 </tr><tr class="layout">
1703 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1704 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1705 second element is a <a href="#t_pointer">pointer</a> to a
1706 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1707 an <tt>i32</tt>.</td>
1708 </tr>
1709</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1711</div>
1712
1713<!-- _______________________________________________________________________ -->
1714<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1715</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1717<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1718
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1719<h5>Overview:</h5>
1720<p>The packed structure type is used to represent a collection of data members
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1721 together in memory. There is no padding between fields. Further, the
1722 alignment of a packed structure is 1 byte. The elements of a packed
1723 structure may be any type that has a size.</p>
1724
1725<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
1726 '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
1727 the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
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; { &lt;type list&gt; } &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">
1737 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1738 <td class="left">A triple of three <tt>i32</tt> values</td>
1739 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1740 <td class="left">
1741<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1742 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1743 second element is a <a href="#t_pointer">pointer</a> to a
1744 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1745 an <tt>i32</tt>.</td>
1746 </tr>
1747</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1749</div>
1750
1751<!-- _______________________________________________________________________ -->
1752<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1753
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1754<div class="doc_text">
1755
1756<h5>Overview:</h5>
1757<p>As in many languages, the pointer type represents a pointer or reference to
1758 another object, which must live in memory. Pointer types may have an optional
1759 address space attribute defining the target-specific numbered address space
1760 where the pointed-to object resides. The default address space is zero.</p>
1761
1762<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
1763 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1765<h5>Syntax:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]1766<pre>
1767 &lt;type&gt; *
1768</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1770<h5>Examples:</h5>
1771<table class="layout">
1772 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1773 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1774 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1775 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1776 </tr>
1777 <tr class="layout">
1778 <td class="left"><tt>i32 (i32 *) *</tt></td>
1779 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1780 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1781 <tt>i32</tt>.</td>
1782 </tr>
1783 <tr class="layout">
1784 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1785 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1786 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1787 </tr>
1788</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1790</div>
1791
1792<!-- _______________________________________________________________________ -->
1793<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1795<div class="doc_text">
1796
1797<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1798<p>A vector type is a simple derived type that represents a vector of elements.
1799 Vector types are used when multiple primitive data are operated in parallel
1800 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands87598b02009-11-27 13:38:03 +0000[diff] [blame]1801 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1802 <a href="#t_firstclass">first class</a>.</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 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1807</pre>
1808
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1809<p>The number of elements is a constant integer value; elementtype may be any
1810 integer or floating point type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1811
1812<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1813<table class="layout">
1814 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1815 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1816 <td class="left">Vector of 4 32-bit integer values.</td>
1817 </tr>
1818 <tr class="layout">
1819 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1820 <td class="left">Vector of 8 32-bit floating-point values.</td>
1821 </tr>
1822 <tr class="layout">
1823 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1824 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825 </tr>
1826</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1828</div>
1829
1830<!-- _______________________________________________________________________ -->
1831<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1832<div class="doc_text">
1833
1834<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1835<p>Opaque types are used to represent unknown types in the system. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1836 corresponds (for example) to the C notion of a forward declared structure
1837 type. In LLVM, opaque types can eventually be resolved to any type (not just
1838 a structure type).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1839
1840<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1841<pre>
1842 opaque
1843</pre>
1844
1845<h5>Examples:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1846<table class="layout">
1847 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1848 <td class="left"><tt>opaque</tt></td>
1849 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1850 </tr>
1851</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1853</div>
1854
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1855<!-- ======================================================================= -->
1856<div class="doc_subsection">
1857 <a name="t_uprefs">Type Up-references</a>
1858</div>
1859
1860<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1861
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1862<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1863<p>An "up reference" allows you to refer to a lexically enclosing type without
1864 requiring it to have a name. For instance, a structure declaration may
1865 contain a pointer to any of the types it is lexically a member of. Example
1866 of up references (with their equivalent as named type declarations)
1867 include:</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1868
1869<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1870 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1871 { \2 }* %y = type { %y }*
1872 \1* %z = type %z*
1873</pre>
1874
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1875<p>An up reference is needed by the asmprinter for printing out cyclic types
1876 when there is no declared name for a type in the cycle. Because the
1877 asmprinter does not want to print out an infinite type string, it needs a
1878 syntax to handle recursive types that have no names (all names are optional
1879 in llvm IR).</p>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1880
1881<h5>Syntax:</h5>
1882<pre>
1883 \&lt;level&gt;
1884</pre>
1885
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1886<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]1887
1888<h5>Examples:</h5>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1889<table class="layout">
1890 <tr class="layout">
1891 <td class="left"><tt>\1*</tt></td>
1892 <td class="left">Self-referential pointer.</td>
1893 </tr>
1894 <tr class="layout">
1895 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1896 <td class="left">Recursive structure where the upref refers to the out-most
1897 structure.</td>
1898 </tr>
1899</table>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1900
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1901</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1902
1903<!-- *********************************************************************** -->
1904<div class="doc_section"> <a name="constants">Constants</a> </div>
1905<!-- *********************************************************************** -->
1906
1907<div class="doc_text">
1908
1909<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1910 them all and their syntax.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1911
1912</div>
1913
1914<!-- ======================================================================= -->
1915<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1916
1917<div class="doc_text">
1918
1919<dl>
1920 <dt><b>Boolean constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1921 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]1922 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1923
1924 <dt><b>Integer constants</b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1925 <dd>Standard integers (such as '4') are constants of
1926 the <a href="#t_integer">integer</a> type. Negative numbers may be used
1927 with integer types.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1928
1929 <dt><b>Floating point constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1930 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1931 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
1932 notation (see below). The assembler requires the exact decimal value of a
1933 floating-point constant. For example, the assembler accepts 1.25 but
1934 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1935 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1936
1937 <dt><b>Null pointer constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1938 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1939 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1940</dl>
1941
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1942<p>The one non-intuitive notation for constants is the hexadecimal form of
1943 floating point constants. For example, the form '<tt>double
1944 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
1945 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
1946 constants are required (and the only time that they are generated by the
1947 disassembler) is when a floating point constant must be emitted but it cannot
1948 be represented as a decimal floating point number in a reasonable number of
1949 digits. For example, NaN's, infinities, and other special values are
1950 represented in their IEEE hexadecimal format so that assembly and disassembly
1951 do not cause any bits to change in the constants.</p>
1952
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1953<p>When using the hexadecimal form, constants of types float and double are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1954 represented using the 16-digit form shown above (which matches the IEEE754
1955 representation for double); float values must, however, be exactly
1956 representable as IEE754 single precision. Hexadecimal format is always used
1957 for long double, and there are three forms of long double. The 80-bit format
1958 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
1959 The 128-bit format used by PowerPC (two adjacent doubles) is represented
1960 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
1961 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
1962 currently supported target uses this format. Long doubles will only work if
1963 they match the long double format on your target. All hexadecimal formats
1964 are big-endian (sign bit at the left).</p>
1965
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1966</div>
1967
1968<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1969<div class="doc_subsection">
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]1970<a name="aggregateconstants"></a> <!-- old anchor -->
1971<a name="complexconstants">Complex Constants</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1972</div>
1973
1974<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1975
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1976<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1977 constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1978
1979<dl>
1980 <dt><b>Structure constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1981 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1982 type definitions (a comma separated list of elements, surrounded by braces
1983 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1984 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
1985 Structure constants must have <a href="#t_struct">structure type</a>, and
1986 the number and types of elements must match those specified by the
1987 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988
1989 <dt><b>Array constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1990 <dd>Array constants are represented with notation similar to array type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1991 definitions (a comma separated list of elements, surrounded by square
1992 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
1993 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
1994 the number and types of elements must match those specified by the
1995 type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1996
1997 <dt><b>Vector constants</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1998 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]1999 definitions (a comma separated list of elements, surrounded by
2000 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2001 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2002 have <a href="#t_vector">vector type</a>, and the number and types of
2003 elements must match those specified by the type.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2004
2005 <dt><b>Zero initialization</b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2006 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2007 value to zero of <em>any</em> type, including scalar and aggregate types.
2008 This is often used to avoid having to print large zero initializers
2009 (e.g. for large arrays) and is always exactly equivalent to using explicit
2010 zero initializers.</dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2011
2012 <dt><b>Metadata node</b></dt>
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]2013 <dd>A metadata node is a structure-like constant with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2014 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2015 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2016 be interpreted as part of the instruction stream, metadata is a place to
2017 attach additional information such as debug info.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2018</dl>
2019
2020</div>
2021
2022<!-- ======================================================================= -->
2023<div class="doc_subsection">
2024 <a name="globalconstants">Global Variable and Function Addresses</a>
2025</div>
2026
2027<div class="doc_text">
2028
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2029<p>The addresses of <a href="#globalvars">global variables</a>
2030 and <a href="#functionstructure">functions</a> are always implicitly valid
2031 (link-time) constants. These constants are explicitly referenced when
2032 the <a href="#identifiers">identifier for the global</a> is used and always
2033 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2034 legal LLVM file:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2035
2036<div class="doc_code">
2037<pre>
2038@X = global i32 17
2039@Y = global i32 42
2040@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
2041</pre>
2042</div>
2043
2044</div>
2045
2046<!-- ======================================================================= -->
2047<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
2048<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2049
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2050<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]2051 indicates that the user of the value may receive an unspecified bit-pattern.
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2052 Undefined values may be of any type (other than label or void) and be used
2053 anywhere a constant is permitted.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2054
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2055<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2056 program is well defined no matter what value is used. This gives the
2057 compiler more freedom to optimize. Here are some examples of (potentially
2058 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2059
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2060
2061<div class="doc_code">
2062<pre>
2063 %A = add %X, undef
2064 %B = sub %X, undef
2065 %C = xor %X, undef
2066Safe:
2067 %A = undef
2068 %B = undef
2069 %C = undef
2070</pre>
2071</div>
2072
2073<p>This is safe because all of the output bits are affected by the undef bits.
2074Any output bit can have a zero or one depending on the input bits.</p>
2075
2076<div class="doc_code">
2077<pre>
2078 %A = or %X, undef
2079 %B = and %X, undef
2080Safe:
2081 %A = -1
2082 %B = 0
2083Unsafe:
2084 %A = undef
2085 %B = undef
2086</pre>
2087</div>
2088
2089<p>These logical operations have bits that are not always affected by the input.
2090For example, if "%X" has a zero bit, then the output of the 'and' operation will
2091always be a zero, no matter what the corresponding bit from the undef is. As
Chris Lattner9d1e4fa2009-09-11 01:49:31 +0000[diff] [blame]2092such, 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]2093However, it is safe to assume that all bits of the undef could be 0, and
2094optimize the and to 0. Likewise, it is safe to assume that all the bits of
2095the 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]2096-1.</p>
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2097
2098<div class="doc_code">
2099<pre>
2100 %A = select undef, %X, %Y
2101 %B = select undef, 42, %Y
2102 %C = select %X, %Y, undef
2103Safe:
2104 %A = %X (or %Y)
2105 %B = 42 (or %Y)
2106 %C = %Y
2107Unsafe:
2108 %A = undef
2109 %B = undef
2110 %C = undef
2111</pre>
2112</div>
2113
2114<p>This set of examples show that undefined select (and conditional branch)
2115conditions can go "either way" but they have to come from one of the two
2116operands. In the %A example, if %X and %Y were both known to have a clear low
2117bit, then %A would have to have a cleared low bit. However, in the %C example,
2118the optimizer is allowed to assume that the undef operand could be the same as
2119%Y, allowing the whole select to be eliminated.</p>
2120
2121
2122<div class="doc_code">
2123<pre>
2124 %A = xor undef, undef
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2125
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2126 %B = undef
2127 %C = xor %B, %B
2128
2129 %D = undef
2130 %E = icmp lt %D, 4
2131 %F = icmp gte %D, 4
2132
2133Safe:
2134 %A = undef
2135 %B = undef
2136 %C = undef
2137 %D = undef
2138 %E = undef
2139 %F = undef
2140</pre>
2141</div>
2142
2143<p>This example points out that two undef operands are not necessarily the same.
2144This can be surprising to people (and also matches C semantics) where they
2145assume that "X^X" is always zero, even if X is undef. This isn't true for a
2146number of reasons, but the short answer is that an undef "variable" can
2147arbitrarily change its value over its "live range". This is true because the
2148"variable" doesn't actually <em>have a live range</em>. Instead, the value is
2149logically read from arbitrary registers that happen to be around when needed,
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2150so the value is not necessarily consistent over time. In fact, %A and %C need
Chris Lattnerc802e482009-09-08 15:13:16 +0000[diff] [blame]2151to have the same semantics or the core LLVM "replace all uses with" concept
Chris Lattner3d72cd82009-09-07 22:52:39 +0000[diff] [blame]2152would not hold.</p>
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2153
2154<div class="doc_code">
2155<pre>
2156 %A = fdiv undef, %X
2157 %B = fdiv %X, undef
2158Safe:
2159 %A = undef
2160b: unreachable
2161</pre>
2162</div>
2163
2164<p>These examples show the crucial difference between an <em>undefined
2165value</em> and <em>undefined behavior</em>. An undefined value (like undef) is
2166allowed to have an arbitrary bit-pattern. This means that the %A operation
2167can be constant folded to undef because the undef could be an SNaN, and fdiv is
2168not (currently) defined on SNaN's. However, in the second example, we can make
2169a more aggressive assumption: because the undef is allowed to be an arbitrary
2170value, 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]2171has <em>undefined behavior</em>, we are allowed to assume that the operation
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2172does not execute at all. This allows us to delete the divide and all code after
2173it: since the undefined operation "can't happen", the optimizer can assume that
2174it occurs in dead code.
2175</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2176
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2177<div class="doc_code">
2178<pre>
2179a: store undef -> %X
2180b: store %X -> undef
2181Safe:
2182a: &lt;deleted&gt;
2183b: unreachable
2184</pre>
2185</div>
2186
2187<p>These examples reiterate the fdiv example: a store "of" an undefined value
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2188can be assumed to not have any effect: we can assume that the value is
Chris Lattner466291f2009-09-07 23:33:52 +0000[diff] [blame]2189overwritten with bits that happen to match what was already there. However, a
2190store "to" an undefined location could clobber arbitrary memory, therefore, it
2191has undefined behavior.</p>
2192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2193</div>
2194
2195<!-- ======================================================================= -->
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2196<div class="doc_subsection"><a name="blockaddress">Addresses of Basic
2197 Blocks</a></div>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2198<div class="doc_text">
2199
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2200<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2201
2202<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner24f2e852009-10-27 21:49:40 +0000[diff] [blame]2203 basic block in the specified function, and always has an i8* type. Taking
Chris Lattner620cead2009-11-01 01:27:45 +0000[diff] [blame]2204 the address of the entry block is illegal.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2205
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2206<p>This value only has defined behavior when used as an operand to the
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2207 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction or for comparisons
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2208 against null. Pointer equality tests between labels addresses is undefined
2209 behavior - though, again, comparison against null is ok, and no label is
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2210 equal to the null pointer. This may also be passed around as an opaque
2211 pointer sized value as long as the bits are not inspected. This allows
Chris Lattner0bae7b32009-10-27 21:44:20 +0000[diff] [blame]2212 <tt>ptrtoint</tt> and arithmetic to be performed on these values so long as
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2213 the original value is reconstituted before the <tt>indirectbr</tt>.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2214
Chris Lattner29246b52009-10-27 21:19:13 +0000[diff] [blame]2215<p>Finally, some targets may provide defined semantics when
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2216 using the value as the operand to an inline assembly, but that is target
2217 specific.
2218 </p>
2219
2220</div>
2221
2222
2223<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2224<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
2225</div>
2226
2227<div class="doc_text">
2228
2229<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2230 to be used as constants. Constant expressions may be of
2231 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2232 operation that does not have side effects (e.g. load and call are not
2233 supported). The following is the syntax for constant expressions:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2234
2235<dl>
2236 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2237 <dd>Truncate a constant to another type. The bit size of CST must be larger
2238 than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2239
2240 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2241 <dd>Zero extend a constant to another type. The bit size of CST must be
2242 smaller or equal to the bit size of TYPE. Both types must be
2243 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244
2245 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2246 <dd>Sign extend a constant to another type. The bit size of CST must be
2247 smaller or equal to the bit size of TYPE. Both types must be
2248 integers.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2249
2250 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2251 <dd>Truncate a floating point constant to another floating point type. The
2252 size of CST must be larger than the size of TYPE. Both types must be
2253 floating point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2254
2255 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2256 <dd>Floating point extend a constant to another type. The size of CST must be
2257 smaller or equal to the size of TYPE. Both types must be floating
2258 point.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2259
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]2260 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2261 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2262 constant. TYPE must be a scalar or vector integer type. CST must be of
2263 scalar or vector floating point type. Both CST and TYPE must be scalars,
2264 or vectors of the same number of elements. If the value won't fit in the
2265 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2266
2267 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
2268 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2269 constant. TYPE must be a scalar or vector integer type. CST must be of
2270 scalar or vector floating point type. Both CST and TYPE must be scalars,
2271 or vectors of the same number of elements. If the value won't fit in the
2272 integer type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2273
2274 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
2275 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2276 constant. TYPE must be a scalar or vector floating point type. CST must be
2277 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2278 vectors of the same number of elements. If the value won't fit in the
2279 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2280
2281 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2282 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2283 constant. TYPE must be a scalar or vector floating point type. CST must be
2284 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2285 vectors of the same number of elements. If the value won't fit in the
2286 floating point type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287
2288 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2289 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2290 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2291 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2292 make it fit in <tt>TYPE</tt>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2293
2294 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2295 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2296 type. CST must be of integer type. The CST value is zero extended,
2297 truncated, or unchanged to make it fit in a pointer size. This one is
2298 <i>really</i> dangerous!</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2299
2300 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2301 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2302 are the same as those for the <a href="#i_bitcast">bitcast
2303 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2304
2305 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]2306 <dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2307 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2308 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2309 instruction, the index list may have zero or more indexes, which are
2310 required to make sense for the type of "CSTPTR".</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311
2312 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2313 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2314
2315 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2316 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2317
2318 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2319 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2320
2321 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2322 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2323 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2324
2325 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2326 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2327 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2328
2329 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2330 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2331 constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2332
2333 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2334 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2335 be any of the <a href="#binaryops">binary</a>
2336 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2337 on operands are the same as those for the corresponding instruction
2338 (e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2339</dl>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2341</div>
2342
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2343<!-- ======================================================================= -->
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]2344<div class="doc_subsection"><a name="metadata">Metadata Nodes and Metadata Strings</a>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2345</div>
2346
2347<div class="doc_text">
2348
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]2349<p>Metadata provides a way to attach arbitrary data to the instruction
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2350 stream without affecting the behaviour of the program. There are two
2351 metadata primitives, strings and nodes. All metadata has the
2352 <tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2353 point ('<tt>!</tt>').</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2354
2355<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2356 any character by escaping non-printable characters with "\xx" where "xx" is
2357 the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2358
2359<p>Metadata nodes are represented with notation similar to structure constants
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2360 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2361 exclamation point). For example: "<tt>!{ metadata !"test\00", i32
2362 10}</tt>".</p>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2363
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2364<p>A metadata node will attempt to track changes to the values it holds. In the
2365 event that a value is deleted, it will be replaced with a typeless
2366 "<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2367
Devang Patela4bb6792010-01-11 19:35:55 +0000[diff] [blame]2368<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2369 metadata nodes. For example: "<tt>!foo = metadata !{!4, !3}</tt>".
Devang Patelc5bb7252010-01-05 20:41:31 +0000[diff] [blame]2370
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2371<p>Optimizations may rely on metadata to provide additional information about
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2372 the program that isn't available in the instructions, or that isn't easily
2373 computable. Similarly, the code generator may expect a certain metadata
2374 format to be used to express debugging information.</p>
2375
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2376</div>
2377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378<!-- *********************************************************************** -->
2379<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2380<!-- *********************************************************************** -->
2381
2382<!-- ======================================================================= -->
2383<div class="doc_subsection">
2384<a name="inlineasm">Inline Assembler Expressions</a>
2385</div>
2386
2387<div class="doc_text">
2388
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2389<p>LLVM supports inline assembler expressions (as opposed
2390 to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
2391 a special value. This value represents the inline assembler as a string
2392 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2393 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2394 expression has side effects, and a flag indicating whether the function
2395 containing the asm needs to align its stack conservatively. An example
2396 inline assembler expression is:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2397
2398<div class="doc_code">
2399<pre>
2400i32 (i32) asm "bswap $0", "=r,r"
2401</pre>
2402</div>
2403
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2404<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2405 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2406 have:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2407
2408<div class="doc_code">
2409<pre>
2410%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2411</pre>
2412</div>
2413
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2414<p>Inline asms with side effects not visible in the constraint list must be
2415 marked as having side effects. This is done through the use of the
2416 '<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2417
2418<div class="doc_code">
2419<pre>
2420call void asm sideeffect "eieio", ""()
2421</pre>
2422</div>
2423
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2424<p>In some cases inline asms will contain code that will not work unless the
2425 stack is aligned in some way, such as calls or SSE instructions on x86,
2426 yet will not contain code that does that alignment within the asm.
2427 The compiler should make conservative assumptions about what the asm might
2428 contain and should generate its usual stack alignment code in the prologue
2429 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2430
2431<div class="doc_code">
2432<pre>
Dale Johannesen5ee3e4b2009-10-21 23:28:00 +0000[diff] [blame]2433call void asm alignstack "eieio", ""()
Dale Johannesen648950f2009-10-13 21:56:55 +0000[diff] [blame]2434</pre>
2435</div>
2436
2437<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2438 first.</p>
2439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2440<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2441 documented here. Constraints on what can be done (e.g. duplication, moving,
2442 etc need to be documented). This is probably best done by reference to
2443 another document that covers inline asm from a holistic perspective.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2444
2445</div>
2446
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2447
2448<!-- *********************************************************************** -->
2449<div class="doc_section">
2450 <a name="intrinsic_globals">Intrinsic Global Variables</a>
2451</div>
2452<!-- *********************************************************************** -->
2453
2454<p>LLVM has a number of "magic" global variables that contain data that affect
2455code generation or other IR semantics. These are documented here. All globals
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2456of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
2457section and all globals that start with "<tt>llvm.</tt>" are reserved for use
2458by LLVM.</p>
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2459
2460<!-- ======================================================================= -->
2461<div class="doc_subsection">
2462<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
2463</div>
2464
2465<div class="doc_text">
2466
2467<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
2468href="#linkage_appending">appending linkage</a>. This array contains a list of
2469pointers to global variables and functions which may optionally have a pointer
2470cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
2471
2472<pre>
2473 @X = global i8 4
2474 @Y = global i32 123
2475
2476 @llvm.used = appending global [2 x i8*] [
2477 i8* @X,
2478 i8* bitcast (i32* @Y to i8*)
2479 ], section "llvm.metadata"
2480</pre>
2481
2482<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
2483compiler, assembler, and linker are required to treat the symbol as if there is
2484a reference to the global that it cannot see. For example, if a variable has
2485internal linkage and no references other than that from the <tt>@llvm.used</tt>
2486list, it cannot be deleted. This is commonly used to represent references from
2487inline asms and other things the compiler cannot "see", and corresponds to
2488"attribute((used))" in GNU C.</p>
2489
2490<p>On some targets, the code generator must emit a directive to the assembler or
2491object file to prevent the assembler and linker from molesting the symbol.</p>
2492
2493</div>
2494
2495<!-- ======================================================================= -->
2496<div class="doc_subsection">
Chris Lattner1e0e0d12009-07-20 06:14:25 +0000[diff] [blame]2497<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
2498</div>
2499
2500<div class="doc_text">
2501
2502<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
2503<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
2504touching the symbol. On targets that support it, this allows an intelligent
2505linker to optimize references to the symbol without being impeded as it would be
2506by <tt>@llvm.used</tt>.</p>
2507
2508<p>This is a rare construct that should only be used in rare circumstances, and
2509should not be exposed to source languages.</p>
2510
2511</div>
2512
2513<!-- ======================================================================= -->
2514<div class="doc_subsection">
Chris Lattner75c24e02009-07-20 05:55:19 +0000[diff] [blame]2515<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
2516</div>
2517
2518<div class="doc_text">
2519
2520<p>TODO: Describe this.</p>
2521
2522</div>
2523
2524<!-- ======================================================================= -->
2525<div class="doc_subsection">
2526<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
2527</div>
2528
2529<div class="doc_text">
2530
2531<p>TODO: Describe this.</p>
2532
2533</div>
2534
2535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2536<!-- *********************************************************************** -->
2537<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2538<!-- *********************************************************************** -->
2539
2540<div class="doc_text">
2541
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2542<p>The LLVM instruction set consists of several different classifications of
2543 instructions: <a href="#terminators">terminator
2544 instructions</a>, <a href="#binaryops">binary instructions</a>,
2545 <a href="#bitwiseops">bitwise binary instructions</a>,
2546 <a href="#memoryops">memory instructions</a>, and
2547 <a href="#otherops">other instructions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2548
2549</div>
2550
2551<!-- ======================================================================= -->
2552<div class="doc_subsection"> <a name="terminators">Terminator
2553Instructions</a> </div>
2554
2555<div class="doc_text">
2556
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2557<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
2558 in a program ends with a "Terminator" instruction, which indicates which
2559 block should be executed after the current block is finished. These
2560 terminator instructions typically yield a '<tt>void</tt>' value: they produce
2561 control flow, not values (the one exception being the
2562 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2563
2564<p>There are six different terminator instructions: the
2565 '<a href="#i_ret"><tt>ret</tt></a>' instruction, the
2566 '<a href="#i_br"><tt>br</tt></a>' instruction, the
2567 '<a href="#i_switch"><tt>switch</tt></a>' instruction, the
Bill Wendlingb4ae2292009-11-02 00:25:26 +0000[diff] [blame]2568 '<a href="#i_indirectbr">'<tt>indirectbr</tt></a>' Instruction, the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2569 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
2570 '<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
2571 '<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572
2573</div>
2574
2575<!-- _______________________________________________________________________ -->
2576<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2577Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2581<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2582<pre>
2583 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]2584 ret void <i>; Return from void function</i>
2585</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2586
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2587<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2588<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
2589 a value) from a function back to the caller.</p>
2590
2591<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
2592 value and then causes control flow, and one that just causes control flow to
2593 occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2595<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2596<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
2597 return value. The type of the return value must be a
2598 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2599
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2600<p>A function is not <a href="#wellformed">well formed</a> if it it has a
2601 non-void return type and contains a '<tt>ret</tt>' instruction with no return
2602 value or a return value with a type that does not match its type, or if it
2603 has a void return type and contains a '<tt>ret</tt>' instruction with a
2604 return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2606<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2607<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
2608 the calling function's context. If the caller is a
2609 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
2610 instruction after the call. If the caller was an
2611 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
2612 the beginning of the "normal" destination block. If the instruction returns
2613 a value, that value shall set the call or invoke instruction's return
2614 value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2617<pre>
2618 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2619 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2620 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]2621</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2622
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2623</div>
2624<!-- _______________________________________________________________________ -->
2625<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2630<pre>
2631 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]2632</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2635<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
2636 different basic block in the current function. There are two forms of this
2637 instruction, corresponding to a conditional branch and an unconditional
2638 branch.</p>
2639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2640<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2641<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
2642 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
2643 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
2644 target.</p>
2645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2646<h5>Semantics:</h5>
2647<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2648 argument is evaluated. If the value is <tt>true</tt>, control flows to the
2649 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2650 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2652<h5>Example:</h5>
Bill Wendling6ec40612009-07-20 02:39:26 +0000[diff] [blame]2653<pre>
2654Test:
2655 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
2656 br i1 %cond, label %IfEqual, label %IfUnequal
2657IfEqual:
2658 <a href="#i_ret">ret</a> i32 1
2659IfUnequal:
2660 <a href="#i_ret">ret</a> i32 0
2661</pre>
2662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2665<!-- _______________________________________________________________________ -->
2666<div class="doc_subsubsection">
2667 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2668</div>
2669
2670<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2672<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2673<pre>
2674 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2675</pre>
2676
2677<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2678<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]2679 several different places. It is a generalization of the '<tt>br</tt>'
2680 instruction, allowing a branch to occur to one of many possible
2681 destinations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2682
2683<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2684<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2685 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
2686 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
2687 The table is not allowed to contain duplicate constant entries.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2688
2689<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2690<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2691 destinations. When the '<tt>switch</tt>' instruction is executed, this table
2692 is searched for the given value. If the value is found, control flow is
Benjamin Kramer5fb9d7e2009-10-12 14:46:08 +0000[diff] [blame]2693 transferred to the corresponding destination; otherwise, control flow is
2694 transferred to the default destination.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695
2696<h5>Implementation:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2697<p>Depending on properties of the target machine and the particular
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2698 <tt>switch</tt> instruction, this instruction may be code generated in
2699 different ways. For example, it could be generated as a series of chained
2700 conditional branches or with a lookup table.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2701
2702<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2703<pre>
2704 <i>; Emulate a conditional br instruction</i>
2705 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2706 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2707
2708 <i>; Emulate an unconditional br instruction</i>
2709 switch i32 0, label %dest [ ]
2710
2711 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2712 switch i32 %val, label %otherwise [ i32 0, label %onzero
2713 i32 1, label %onone
2714 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2715</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2716
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2717</div>
2718
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2719
2720<!-- _______________________________________________________________________ -->
2721<div class="doc_subsubsection">
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2722 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2723</div>
2724
2725<div class="doc_text">
2726
2727<h5>Syntax:</h5>
2728<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2729 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]2730</pre>
2731
2732<h5>Overview:</h5>
2733
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2734<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2735 within the current function, whose address is specified by
Chris Lattnerd07c8372009-10-27 21:01:34 +0000[diff] [blame]2736 "<tt>address</tt>". Address must be derived from a <a
2737 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2738
2739<h5>Arguments:</h5>
2740
2741<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
2742 rest of the arguments indicate the full set of possible destinations that the
2743 address may point to. Blocks are allowed to occur multiple times in the
2744 destination list, though this isn't particularly useful.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]2745
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2746<p>This destination list is required so that dataflow analysis has an accurate
2747 understanding of the CFG.</p>
2748
2749<h5>Semantics:</h5>
2750
2751<p>Control transfers to the block specified in the address argument. All
2752 possible destination blocks must be listed in the label list, otherwise this
2753 instruction has undefined behavior. This implies that jumps to labels
2754 defined in other functions have undefined behavior as well.</p>
2755
2756<h5>Implementation:</h5>
2757
2758<p>This is typically implemented with a jump through a register.</p>
2759
2760<h5>Example:</h5>
2761<pre>
Chris Lattner4c3800f2009-10-28 00:19:10 +0000[diff] [blame]2762 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattnere0787282009-10-27 19:13:16 +0000[diff] [blame]2763</pre>
2764
2765</div>
2766
2767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768<!-- _______________________________________________________________________ -->
2769<div class="doc_subsubsection">
2770 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2771</div>
2772
2773<div class="doc_text">
2774
2775<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2776<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2777 &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]2778 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2779</pre>
2780
2781<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2783 function, with the possibility of control flow transfer to either the
2784 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
2785 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
2786 control flow will return to the "normal" label. If the callee (or any
2787 indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
2788 instruction, control is interrupted and continued at the dynamically nearest
2789 "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2790
2791<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792<p>This instruction requires several arguments:</p>
2793
2794<ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2795 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
2796 convention</a> the call should use. If none is specified, the call
2797 defaults to using C calling conventions.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2798
2799 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2800 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
2801 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803 <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]2804 function value being invoked. In most cases, this is a direct function
2805 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
2806 off an arbitrary pointer to function value.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807
2808 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2809 function to be invoked. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2810
2811 <li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2812 signature argument types. If the function signature indicates the
2813 function accepts a variable number of arguments, the extra arguments can
2814 be specified.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2815
2816 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2817 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2818
2819 <li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2820 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2821
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2822 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2823 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2824 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2825</ol>
2826
2827<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2828<p>This instruction is designed to operate as a standard
2829 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
2830 primary difference is that it establishes an association with a label, which
2831 is used by the runtime library to unwind the stack.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2832
2833<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2834 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2835 exception. Additionally, this is important for implementation of
2836 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2837
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2838<p>For the purposes of the SSA form, the definition of the value returned by the
2839 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
2840 block to the "normal" label. If the callee unwinds then no return value is
2841 available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2843<h5>Example:</h5>
2844<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2845 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2847 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848 unwind label %TestCleanup <i>; {i32}:retval set</i>
2849</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2850
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2851</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2852
2853<!-- _______________________________________________________________________ -->
2854
2855<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2856Instruction</a> </div>
2857
2858<div class="doc_text">
2859
2860<h5>Syntax:</h5>
2861<pre>
2862 unwind
2863</pre>
2864
2865<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2867 at the first callee in the dynamic call stack which used
2868 an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
2869 This is primarily used to implement exception handling.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2870
2871<h5>Semantics:</h5>
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2872<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2873 immediately halt. The dynamic call stack is then searched for the
2874 first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
2875 Once found, execution continues at the "exceptional" destination block
2876 specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
2877 instruction in the dynamic call chain, undefined behavior results.</p>
2878
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2879</div>
2880
2881<!-- _______________________________________________________________________ -->
2882
2883<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2884Instruction</a> </div>
2885
2886<div class="doc_text">
2887
2888<h5>Syntax:</h5>
2889<pre>
2890 unreachable
2891</pre>
2892
2893<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2894<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2895 instruction is used to inform the optimizer that a particular portion of the
2896 code is not reachable. This can be used to indicate that the code after a
2897 no-return function cannot be reached, and other facts.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2898
2899<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2900<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2901
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2902</div>
2903
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2904<!-- ======================================================================= -->
2905<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2906
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2907<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2908
2909<p>Binary operators are used to do most of the computation in a program. They
2910 require two operands of the same type, execute an operation on them, and
2911 produce a single value. The operands might represent multiple data, as is
2912 the case with the <a href="#t_vector">vector</a> data type. The result value
2913 has the same type as its operands.</p>
2914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915<p>There are several different binary operators:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2916
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2917</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2919<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2920<div class="doc_subsubsection">
2921 <a name="i_add">'<tt>add</tt>' Instruction</a>
2922</div>
2923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2924<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2926<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2927<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2928 &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]2929 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2930 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2931 &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]2932</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2934<h5>Overview:</h5>
2935<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2937<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2938<p>The two arguments to the '<tt>add</tt>' instruction must
2939 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2940 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2943<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2944
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2945<p>If the sum has unsigned overflow, the result returned is the mathematical
2946 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]2947
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2948<p>Because LLVM integers use a two's complement representation, this instruction
2949 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2950
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]2951<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
2952 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
2953 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
2954 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]2955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2956<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2957<pre>
2958 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2960
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2961</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2963<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2964<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2965 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2966</div>
2967
2968<div class="doc_text">
2969
2970<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2971<pre>
2972 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2973</pre>
2974
2975<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2976<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2977
2978<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2979<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2980 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2981 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2982
2983<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2984<p>The value produced is the floating point sum of the two operands.</p>
2985
2986<h5>Example:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2987<pre>
2988 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2989</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2990
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2991</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]2992
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2993<!-- _______________________________________________________________________ -->
2994<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2995 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2996</div>
2997
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2998<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3000<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3001<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3002 &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]3003 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3004 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3005 &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]3006</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3007
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3008<h5>Overview:</h5>
3009<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3010 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3011
3012<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3013 '<tt>neg</tt>' instruction present in most other intermediate
3014 representations.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3016<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3017<p>The two arguments to the '<tt>sub</tt>' instruction must
3018 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3019 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3020
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3021<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3022<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3023
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3024<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3025 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3026 result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3027
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3028<p>Because LLVM integers use a two's complement representation, this instruction
3029 is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3030
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3031<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3032 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3033 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
3034 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3036<h5>Example:</h5>
3037<pre>
3038 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
3039 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
3040</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3042</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3044<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3045<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3046 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
3047</div>
3048
3049<div class="doc_text">
3050
3051<h5>Syntax:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3052<pre>
3053 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3054</pre>
3055
3056<h5>Overview:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3057<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3058 operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3059
3060<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3061 '<tt>fneg</tt>' instruction present in most other intermediate
3062 representations.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3063
3064<h5>Arguments:</h5>
Bill Wendling1a2630a2009-07-20 02:32:41 +0000[diff] [blame]3065<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3066 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3067 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3068
3069<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3070<p>The value produced is the floating point difference of the two operands.</p>
3071
3072<h5>Example:</h5>
3073<pre>
3074 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3075 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3076</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3077
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3078</div>
3079
3080<!-- _______________________________________________________________________ -->
3081<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3082 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
3083</div>
3084
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3085<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3086
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3087<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3088<pre>
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3089 &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]3090 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3091 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3092 &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]3093</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3094
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3095<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3096<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3097
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3098<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3099<p>The two arguments to the '<tt>mul</tt>' instruction must
3100 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3101 integer values. Both arguments must have identical types.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3103<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3104<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3105
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3106<p>If the result of the multiplication has unsigned overflow, the result
3107 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3108 width of the result.</p>
3109
3110<p>Because LLVM integers use a two's complement representation, and the result
3111 is the same width as the operands, this instruction returns the correct
3112 result for both signed and unsigned integers. If a full product
3113 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3114 be sign-extended or zero-extended as appropriate to the width of the full
3115 product.</p>
3116
Dan Gohman46e96012009-07-22 22:44:56 +0000[diff] [blame]3117<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3118 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3119 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
3120 is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3122<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3123<pre>
3124 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3125</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3127</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3129<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3130<div class="doc_subsubsection">
3131 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
3132</div>
3133
3134<div class="doc_text">
3135
3136<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3137<pre>
3138 &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]3139</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3140
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3141<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3142<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3143
3144<h5>Arguments:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3145<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3146 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3147 floating point values. Both arguments must have identical types.</p>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3148
3149<h5>Semantics:</h5>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3150<p>The value produced is the floating point product of the two operands.</p>
3151
3152<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3153<pre>
3154 &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]3155</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3156
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]3157</div>
3158
3159<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3160<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
3161</a></div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3162
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3163<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3164
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3165<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3166<pre>
3167 &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]3168</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3169
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3170<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3171<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3172
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3173<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3174<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3175 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3176 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3177
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178<h5>Semantics:</h5>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3179<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3180
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3181<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3182 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3183
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3184<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3185
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3186<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3187<pre>
3188 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3189</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3190
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3192
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3193<!-- _______________________________________________________________________ -->
3194<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
3195</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3197<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3198
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3199<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3200<pre>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3201 &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]3202 &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]3203</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3204
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3205<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3206<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3208<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3209<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3210 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3211 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3213<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3214<p>The value produced is the signed integer quotient of the two operands rounded
3215 towards zero.</p>
3216
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3217<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3218 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3219
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3220<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3221 undefined behavior; this is a rare case, but can occur, for example, by doing
3222 a 32-bit division of -2147483648 by -1.</p>
3223
Dan Gohman67fa48e2009-07-22 00:04:19 +0000[diff] [blame]3224<p>If the <tt>exact</tt> keyword is present, the result value of the
3225 <tt>sdiv</tt> is undefined if the result would be rounded or if overflow
3226 would occur.</p>
Dan Gohmaned5fcb22009-07-20 22:41:19 +0000[diff] [blame]3227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3228<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3229<pre>
3230 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3231</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3232
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3233</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3234
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3235<!-- _______________________________________________________________________ -->
3236<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
3237Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3239<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3240
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3241<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3242<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3243 &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]3244</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3245
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3246<h5>Overview:</h5>
3247<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3249<h5>Arguments:</h5>
3250<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3251 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3252 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3253
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3254<h5>Semantics:</h5>
3255<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3257<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3258<pre>
3259 &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]3260</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3262</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3264<!-- _______________________________________________________________________ -->
3265<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
3266</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3268<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3270<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3271<pre>
3272 &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]3273</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3274
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3275<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3276<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
3277 division of its two arguments.</p>
3278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3279<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3280<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3281 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3282 values. Both arguments must have identical types.</p>
3283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3284<h5>Semantics:</h5>
3285<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3286 This instruction always performs an unsigned division to get the
3287 remainder.</p>
3288
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3289<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3290 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
3291
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3292<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3293
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3294<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3295<pre>
3296 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3297</pre>
3298
3299</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3300
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3301<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3302<div class="doc_subsubsection">
3303 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
3304</div>
3305
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3306<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3307
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3308<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3309<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3310 &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]3311</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3312
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3313<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3314<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
3315 division of its two operands. This instruction can also take
3316 <a href="#t_vector">vector</a> versions of the values in which case the
3317 elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]3318
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3319<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3320<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3321 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3322 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3323
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3324<h5>Semantics:</h5>
3325<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3326 has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
3327 operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
3328 a value. For more information about the difference,
3329 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
3330 Math Forum</a>. For a table of how this is implemented in various languages,
3331 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
3332 Wikipedia: modulo operation</a>.</p>
3333
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3334<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3335 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
3336
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]3337<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3338 Overflow also leads to undefined behavior; this is a rare case, but can
3339 occur, for example, by taking the remainder of a 32-bit division of
3340 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
3341 lets srem be implemented using instructions that return both the result of
3342 the division and the remainder.)</p>
3343
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3345<pre>
3346 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3347</pre>
3348
3349</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3351<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3352<div class="doc_subsubsection">
3353 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
3354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3355<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3356
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3357<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3358<pre>
3359 &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]3360</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3361
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3362<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3363<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
3364 its two operands.</p>
3365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366<h5>Arguments:</h5>
3367<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3368 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3369 floating point values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3370
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3371<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3372<p>This instruction returns the <i>remainder</i> of a division. The remainder
3373 has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3375<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3376<pre>
3377 &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]3378</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3379
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3380</div>
3381
3382<!-- ======================================================================= -->
3383<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
3384Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3386<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3387
3388<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
3389 program. They are generally very efficient instructions and can commonly be
3390 strength reduced from other instructions. They require two operands of the
3391 same type, execute an operation on them, and produce a single value. The
3392 resulting value is the same type as its operands.</p>
3393
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3394</div>
3395
3396<!-- _______________________________________________________________________ -->
3397<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</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; = 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]3405</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3407<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3408<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
3409 a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3411<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3412<p>Both arguments to the '<tt>shl</tt>' instruction must be the
3413 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3414 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3416<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3417<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
3418 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
3419 is (statically or dynamically) negative or equal to or larger than the number
3420 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>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3423
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3424<h5>Example:</h5>
3425<pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
3427 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
3428 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3429 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3430 &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]3431</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3433</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3435<!-- _______________________________________________________________________ -->
3436<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
3437Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3439<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3441<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3442<pre>
3443 &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]3444</pre>
3445
3446<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3447<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
3448 operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3449
3450<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3451<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3452 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3453 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3454
3455<h5>Semantics:</h5>
3456<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3457 significant bits of the result will be filled with zero bits after the shift.
3458 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
3459 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
3460 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
3461 shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3462
3463<h5>Example:</h5>
3464<pre>
3465 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
3466 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
3467 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
3468 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3469 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3470 &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]3471</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3472
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3473</div>
3474
3475<!-- _______________________________________________________________________ -->
3476<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3477Instruction</a> </div>
3478<div class="doc_text">
3479
3480<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3481<pre>
3482 &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]3483</pre>
3484
3485<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3486<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3487 operand shifted to the right a specified number of bits with sign
3488 extension.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3489
3490<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3491<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3492 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3493 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3494
3495<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3496<p>This instruction always performs an arithmetic shift right operation, The
3497 most significant bits of the result will be filled with the sign bit
3498 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
3499 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
3500 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
3501 the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3502
3503<h5>Example:</h5>
3504<pre>
3505 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3506 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3507 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3508 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3509 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3510 &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]3511</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3513</div>
3514
3515<!-- _______________________________________________________________________ -->
3516<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3517Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3519<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3521<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3522<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3523 &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]3524</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3526<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3527<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
3528 operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3530<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3531<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3532 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3533 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3535<h5>Semantics:</h5>
3536<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3538<table border="1" cellspacing="0" cellpadding="4">
3539 <tbody>
3540 <tr>
3541 <td>In0</td>
3542 <td>In1</td>
3543 <td>Out</td>
3544 </tr>
3545 <tr>
3546 <td>0</td>
3547 <td>0</td>
3548 <td>0</td>
3549 </tr>
3550 <tr>
3551 <td>0</td>
3552 <td>1</td>
3553 <td>0</td>
3554 </tr>
3555 <tr>
3556 <td>1</td>
3557 <td>0</td>
3558 <td>0</td>
3559 </tr>
3560 <tr>
3561 <td>1</td>
3562 <td>1</td>
3563 <td>1</td>
3564 </tr>
3565 </tbody>
3566</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3568<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3569<pre>
3570 &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]3571 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3572 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3573</pre>
3574</div>
3575<!-- _______________________________________________________________________ -->
3576<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3577
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3578<div class="doc_text">
3579
3580<h5>Syntax:</h5>
3581<pre>
3582 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3583</pre>
3584
3585<h5>Overview:</h5>
3586<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
3587 two operands.</p>
3588
3589<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3590<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3591 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3592 values. Both arguments must have identical types.</p>
3593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3594<h5>Semantics:</h5>
3595<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3597<table border="1" cellspacing="0" cellpadding="4">
3598 <tbody>
3599 <tr>
3600 <td>In0</td>
3601 <td>In1</td>
3602 <td>Out</td>
3603 </tr>
3604 <tr>
3605 <td>0</td>
3606 <td>0</td>
3607 <td>0</td>
3608 </tr>
3609 <tr>
3610 <td>0</td>
3611 <td>1</td>
3612 <td>1</td>
3613 </tr>
3614 <tr>
3615 <td>1</td>
3616 <td>0</td>
3617 <td>1</td>
3618 </tr>
3619 <tr>
3620 <td>1</td>
3621 <td>1</td>
3622 <td>1</td>
3623 </tr>
3624 </tbody>
3625</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3627<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3628<pre>
3629 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3630 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3631 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3632</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3633
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3634</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3635
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3636<!-- _______________________________________________________________________ -->
3637<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3638Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3640<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3641
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3642<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3643<pre>
3644 &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]3645</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3648<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
3649 its two operands. The <tt>xor</tt> is used to implement the "one's
3650 complement" operation, which is the "~" operator in C.</p>
3651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3652<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3653<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3654 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3655 values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3657<h5>Semantics:</h5>
3658<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3660<table border="1" cellspacing="0" cellpadding="4">
3661 <tbody>
3662 <tr>
3663 <td>In0</td>
3664 <td>In1</td>
3665 <td>Out</td>
3666 </tr>
3667 <tr>
3668 <td>0</td>
3669 <td>0</td>
3670 <td>0</td>
3671 </tr>
3672 <tr>
3673 <td>0</td>
3674 <td>1</td>
3675 <td>1</td>
3676 </tr>
3677 <tr>
3678 <td>1</td>
3679 <td>0</td>
3680 <td>1</td>
3681 </tr>
3682 <tr>
3683 <td>1</td>
3684 <td>1</td>
3685 <td>0</td>
3686 </tr>
3687 </tbody>
3688</table>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3690<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3691<pre>
3692 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3693 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3694 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3695 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3696</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3698</div>
3699
3700<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3701<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702 <a name="vectorops">Vector Operations</a>
3703</div>
3704
3705<div class="doc_text">
3706
3707<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3708 target-independent manner. These instructions cover the element-access and
3709 vector-specific operations needed to process vectors effectively. While LLVM
3710 does directly support these vector operations, many sophisticated algorithms
3711 will want to use target-specific intrinsics to take full advantage of a
3712 specific target.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3713
3714</div>
3715
3716<!-- _______________________________________________________________________ -->
3717<div class="doc_subsubsection">
3718 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3719</div>
3720
3721<div class="doc_text">
3722
3723<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3724<pre>
3725 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3726</pre>
3727
3728<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3729<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
3730 from a vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3731
3732
3733<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3734<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
3735 of <a href="#t_vector">vector</a> type. The second operand is an index
3736 indicating the position from which to extract the element. The index may be
3737 a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3738
3739<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3740<p>The result is a scalar of the same type as the element type of
3741 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3742 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3743 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3744
3745<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3747 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3748</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3749
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3750</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3751
3752<!-- _______________________________________________________________________ -->
3753<div class="doc_subsubsection">
3754 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3755</div>
3756
3757<div class="doc_text">
3758
3759<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3760<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3761 &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]3762</pre>
3763
3764<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3765<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
3766 vector at a specified index.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3767
3768<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3769<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
3770 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
3771 whose type must equal the element type of the first operand. The third
3772 operand is an index indicating the position at which to insert the value.
3773 The index may be a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3774
3775<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3776<p>The result is a vector of the same type as <tt>val</tt>. Its element values
3777 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
3778 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3779 results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3780
3781<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3782<pre>
Gabor Greifb2c73142009-10-28 13:14:50 +0000[diff] [blame]3783 &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]3784</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3786</div>
3787
3788<!-- _______________________________________________________________________ -->
3789<div class="doc_subsubsection">
3790 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3791</div>
3792
3793<div class="doc_text">
3794
3795<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3796<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3797 &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]3798</pre>
3799
3800<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3801<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
3802 from two input vectors, returning a vector with the same element type as the
3803 input and length that is the same as the shuffle mask.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3804
3805<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3806<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3807 with types that match each other. The third argument is a shuffle mask whose
3808 element type is always 'i32'. The result of the instruction is a vector
3809 whose length is the same as the shuffle mask and whose element type is the
3810 same as the element type of the first two operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3811
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3812<p>The shuffle mask operand is required to be a constant vector with either
3813 constant integer or undef values.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3814
3815<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3816<p>The elements of the two input vectors are numbered from left to right across
3817 both of the vectors. The shuffle mask operand specifies, for each element of
3818 the result vector, which element of the two input vectors the result element
3819 gets. The element selector may be undef (meaning "don't care") and the
3820 second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821
3822<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3823<pre>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3824 &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]3825 &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]3826 &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]3827 &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]3828 &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]3829 &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]3830 &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]3831 &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]3832</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3833
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3834</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3835
3836<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3837<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3838 <a name="aggregateops">Aggregate Operations</a>
3839</div>
3840
3841<div class="doc_text">
3842
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3843<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3844
3845</div>
3846
3847<!-- _______________________________________________________________________ -->
3848<div class="doc_subsubsection">
3849 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3850</div>
3851
3852<div class="doc_text">
3853
3854<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3855<pre>
3856 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3857</pre>
3858
3859<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3860<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3861 or array element from an aggregate value.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3862
3863<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3864<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
3865 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3866 operands are constant indices to specify which value to extract in a similar
3867 manner as indices in a
3868 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3869
3870<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3871<p>The result is the value at the position in the aggregate specified by the
3872 index operands.</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; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3877</pre>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3878
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3879</div>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3880
3881<!-- _______________________________________________________________________ -->
3882<div class="doc_subsubsection">
3883 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3884</div>
3885
3886<div class="doc_text">
3887
3888<h5>Syntax:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3889<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]3890 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt; <i>; yields &lt;aggregate type&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3891</pre>
3892
3893<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3894<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
3895 array element in an aggregate.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3896
3897
3898<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3899<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
3900 of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
3901 second operand is a first-class value to insert. The following operands are
3902 constant indices indicating the position at which to insert the value in a
3903 similar manner as indices in a
3904 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
3905 value to insert must have the same type as the value identified by the
3906 indices.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3907
3908<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3909<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
3910 that of <tt>val</tt> except that the value at the position specified by the
3911 indices is that of <tt>elt</tt>.</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3912
3913<h5>Example:</h5>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3914<pre>
Jeffrey Yasskine05d7732010-01-11 19:19:26 +0000[diff] [blame]3915 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
3916 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3917</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3918
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3919</div>
3920
3921
3922<!-- ======================================================================= -->
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]3923<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3924 <a name="memoryops">Memory Access and Addressing Operations</a>
3925</div>
3926
3927<div class="doc_text">
3928
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3929<p>A key design point of an SSA-based representation is how it represents
3930 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]3931 very simple. This section describes how to read, write, and allocate
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3932 memory in LLVM.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3933
3934</div>
3935
3936<!-- _______________________________________________________________________ -->
3937<div class="doc_subsubsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3939</div>
3940
3941<div class="doc_text">
3942
3943<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944<pre>
3945 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3946</pre>
3947
3948<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3950 currently executing function, to be automatically released when this function
3951 returns to its caller. The object is always allocated in the generic address
3952 space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3953
3954<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3955<p>The '<tt>alloca</tt>' instruction
3956 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
3957 runtime stack, returning a pointer of the appropriate type to the program.
3958 If "NumElements" is specified, it is the number of elements allocated,
3959 otherwise "NumElements" is defaulted to be one. If a constant alignment is
3960 specified, the value result of the allocation is guaranteed to be aligned to
3961 at least that boundary. If not specified, or if zero, the target can choose
3962 to align the allocation on any convenient boundary compatible with the
3963 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3964
3965<p>'<tt>type</tt>' may be any sized type.</p>
3966
3967<h5>Semantics:</h5>
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3968<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3969 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
3970 memory is automatically released when the function returns. The
3971 '<tt>alloca</tt>' instruction is commonly used to represent automatic
3972 variables that must have an address available. When the function returns
3973 (either with the <tt><a href="#i_ret">ret</a></tt>
3974 or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
3975 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3976
3977<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3979 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3980 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3981 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3982 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3983</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3984
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3985</div>
3986
3987<!-- _______________________________________________________________________ -->
3988<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3989Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3990
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3991<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3992
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3993<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]3994<pre>
3995 &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3996 &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]
3997</pre>
3998
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3999<h5>Overview:</h5>
4000<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4001
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4002<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4003<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4004 from which to load. The pointer must point to
4005 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4006 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
4007 number or order of execution of this <tt>load</tt> with other
4008 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4009 instructions. </p>
4010
4011<p>The optional constant "align" argument specifies the alignment of the
4012 operation (that is, the alignment of the memory address). A value of 0 or an
4013 omitted "align" argument means that the operation has the preferential
4014 alignment for the target. It is the responsibility of the code emitter to
4015 ensure that the alignment information is correct. Overestimating the
4016 alignment results in an undefined behavior. Underestimating the alignment may
4017 produce less efficient code. An alignment of 1 is always safe.</p>
4018
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4019<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4020<p>The location of memory pointed to is loaded. If the value being loaded is of
4021 scalar type then the number of bytes read does not exceed the minimum number
4022 of bytes needed to hold all bits of the type. For example, loading an
4023 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4024 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4025 is undefined if the value was not originally written using a store of the
4026 same type.</p>
4027
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4028<h5>Examples:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4029<pre>
4030 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4031 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4032 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
4033</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4035</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4037<!-- _______________________________________________________________________ -->
4038<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
4039Instruction</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4040
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4043<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4044<pre>
4045 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]4046 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
4047</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4049<h5>Overview:</h5>
4050<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4051
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4052<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4053<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4054 and an address at which to store it. The type of the
4055 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4056 the <a href="#t_firstclass">first class</a> type of the
4057 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked
4058 as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
4059 or order of execution of this <tt>store</tt> with other
4060 volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
4061 instructions.</p>
4062
4063<p>The optional constant "align" argument specifies the alignment of the
4064 operation (that is, the alignment of the memory address). A value of 0 or an
4065 omitted "align" argument means that the operation has the preferential
4066 alignment for the target. It is the responsibility of the code emitter to
4067 ensure that the alignment information is correct. Overestimating the
4068 alignment results in an undefined behavior. Underestimating the alignment may
4069 produce less efficient code. An alignment of 1 is always safe.</p>
4070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4071<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4072<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4073 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4074 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4075 does not exceed the minimum number of bytes needed to hold all bits of the
4076 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4077 writing a value of a type like <tt>i20</tt> with a size that is not an
4078 integral number of bytes, it is unspecified what happens to the extra bits
4079 that do not belong to the type, but they will typically be overwritten.</p>
4080
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4081<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4082<pre>
4083 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]4084 store i32 3, i32* %ptr <i>; yields {void}</i>
4085 %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]4086</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4087
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088</div>
4089
4090<!-- _______________________________________________________________________ -->
4091<div class="doc_subsubsection">
4092 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
4093</div>
4094
4095<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4097<h5>Syntax:</h5>
4098<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4099 &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]4100 &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]4101</pre>
4102
4103<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4104<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
4105 subelement of an aggregate data structure. It performs address calculation
4106 only and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4107
4108<h5>Arguments:</h5>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4109<p>The first argument is always a pointer, and forms the basis of the
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4110 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4111 elements of the aggregate object are indexed. The interpretation of each
4112 index is dependent on the type being indexed into. The first index always
4113 indexes the pointer value given as the first argument, the second index
4114 indexes a value of the type pointed to (not necessarily the value directly
4115 pointed to, since the first index can be non-zero), etc. The first type
4116 indexed into must be a pointer value, subsequent types can be arrays, vectors
4117 and structs. Note that subsequent types being indexed into can never be
4118 pointers, since that would require loading the pointer before continuing
4119 calculation.</p>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4120
4121<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]4122 When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4123 <b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattnere92fc832009-07-29 06:44:13 +0000[diff] [blame]4124 vector, integers of any width are allowed, and they are not required to be
4125 constant.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4127<p>For example, let's consider a C code fragment and how it gets compiled to
4128 LLVM:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4129
4130<div class="doc_code">
4131<pre>
4132struct RT {
4133 char A;
4134 int B[10][20];
4135 char C;
4136};
4137struct ST {
4138 int X;
4139 double Y;
4140 struct RT Z;
4141};
4142
4143int *foo(struct ST *s) {
4144 return &amp;s[1].Z.B[5][13];
4145}
4146</pre>
4147</div>
4148
4149<p>The LLVM code generated by the GCC frontend is:</p>
4150
4151<div class="doc_code">
4152<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]4153%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
4154%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4155
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4156define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4157entry:
4158 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
4159 ret i32* %reg
4160}
4161</pre>
4162</div>
4163
4164<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4165<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]4166 type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
4167 }</tt>' type, a structure. The second index indexes into the third element
4168 of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
4169 i8 }</tt>' type, another structure. The third index indexes into the second
4170 element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
4171 array. The two dimensions of the array are subscripted into, yielding an
4172 '<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
4173 pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4174
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4175<p>Note that it is perfectly legal to index partially through a structure,
4176 returning a pointer to an inner element. Because of this, the LLVM code for
4177 the given testcase is equivalent to:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178
4179<pre>
Dan Gohman47360842009-07-25 02:23:48 +0000[diff] [blame]4180 define i32* @foo(%ST* %s) {
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4181 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
4182 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
4183 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
4184 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
4185 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
4186 ret i32* %t5
4187 }
4188</pre>
4189
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4190<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4191 <tt>getelementptr</tt> is undefined if the base pointer is not an
4192 <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]4193 that would be formed by successive addition of the offsets implied by the
4194 indices to the base address with infinitely precise arithmetic are not an
4195 <i>in bounds</i> address of that allocated object.
Dan Gohman4cba1562009-07-29 16:00:30 +0000[diff] [blame]4196 The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohmanbc4c87f2009-08-20 17:08:17 +0000[diff] [blame]4197 that point into the object, plus the address one byte past the end.</p>
Dan Gohman106b2ae2009-07-27 21:53:46 +0000[diff] [blame]4198
4199<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
4200 the base address with silently-wrapping two's complement arithmetic, and
4201 the result value of the <tt>getelementptr</tt> may be outside the object
4202 pointed to by the base pointer. The result value may not necessarily be
4203 used to access memory though, even if it happens to point into allocated
4204 storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
4205 section for more information.</p>
4206
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4207<p>The getelementptr instruction is often confusing. For some more insight into
4208 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4209
4210<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4211<pre>
4212 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]4213 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
4214 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4215 %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]4216 <i>; yields i8*:eptr</i>
4217 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]4218 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]4219 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4220</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4222</div>
4223
4224<!-- ======================================================================= -->
4225<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
4226</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4228<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4229
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4230<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4231 which all take a single operand and a type. They perform various bit
4232 conversions on the operand.</p>
4233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234</div>
4235
4236<!-- _______________________________________________________________________ -->
4237<div class="doc_subsubsection">
4238 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
4239</div>
4240<div class="doc_text">
4241
4242<h5>Syntax:</h5>
4243<pre>
4244 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4245</pre>
4246
4247<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4248<p>The '<tt>trunc</tt>' instruction truncates its operand to the
4249 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4250
4251<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4252<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
4253 be an <a href="#t_integer">integer</a> type, and a type that specifies the
4254 size and type of the result, which must be
4255 an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
4256 be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
4257 allowed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258
4259<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4260<p>The '<tt>trunc</tt>' instruction truncates the high order bits
4261 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
4262 source size must be larger than the destination size, <tt>trunc</tt> cannot
4263 be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264
4265<h5>Example:</h5>
4266<pre>
4267 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
4268 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4269 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4270</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272</div>
4273
4274<!-- _______________________________________________________________________ -->
4275<div class="doc_subsubsection">
4276 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
4277</div>
4278<div class="doc_text">
4279
4280<h5>Syntax:</h5>
4281<pre>
4282 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4283</pre>
4284
4285<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4286<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4287 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288
4289
4290<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4291<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]4292 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4293 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]4294 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4295 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4296
4297<h5>Semantics:</h5>
4298<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]4299 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4300
4301<p>When zero extending from i1, the result will always be either 0 or 1.</p>
4302
4303<h5>Example:</h5>
4304<pre>
4305 %X = zext i32 257 to i64 <i>; yields i64:257</i>
4306 %Y = zext i1 true to i32 <i>; yields i32:1</i>
4307</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4309</div>
4310
4311<!-- _______________________________________________________________________ -->
4312<div class="doc_subsubsection">
4313 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
4314</div>
4315<div class="doc_text">
4316
4317<h5>Syntax:</h5>
4318<pre>
4319 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4320</pre>
4321
4322<h5>Overview:</h5>
4323<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
4324
4325<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4326<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]4327 <a href="#t_integer">integer</a> type, and a type to cast it to, which must
4328 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]4329 <tt>value</tt> must be smaller than the bit size of the destination type,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4330 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4331
4332<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4333<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
4334 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
4335 of the type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4336
4337<p>When sign extending from i1, the extension always results in -1 or 0.</p>
4338
4339<h5>Example:</h5>
4340<pre>
4341 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
4342 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
4343</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4345</div>
4346
4347<!-- _______________________________________________________________________ -->
4348<div class="doc_subsubsection">
4349 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
4350</div>
4351
4352<div class="doc_text">
4353
4354<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4355<pre>
4356 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4357</pre>
4358
4359<h5>Overview:</h5>
4360<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4361 <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4362
4363<h5>Arguments:</h5>
4364<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4365 point</a> value to cast and a <a href="#t_floating">floating point</a> type
4366 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]4367 <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]4368 <i>no-op cast</i>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369
4370<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4371<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4372 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4373 <a href="#t_floating">floating point</a> type. If the value cannot fit
4374 within the destination type, <tt>ty2</tt>, then the results are
4375 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4376
4377<h5>Example:</h5>
4378<pre>
4379 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4380 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4381</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4382
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4383</div>
4384
4385<!-- _______________________________________________________________________ -->
4386<div class="doc_subsubsection">
4387 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4388</div>
4389<div class="doc_text">
4390
4391<h5>Syntax:</h5>
4392<pre>
4393 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4394</pre>
4395
4396<h5>Overview:</h5>
4397<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]4398 floating point value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4399
4400<h5>Arguments:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4401<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4402 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
4403 a <a href="#t_floating">floating point</a> type to cast it to. The source
4404 type must be smaller than the destination type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4405
4406<h5>Semantics:</h5>
4407<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4408 <a href="#t_floating">floating point</a> type to a larger
4409 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4410 used to make a <i>no-op cast</i> because it always changes bits. Use
4411 <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]4412
4413<h5>Example:</h5>
4414<pre>
4415 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4416 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4417</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4419</div>
4420
4421<!-- _______________________________________________________________________ -->
4422<div class="doc_subsubsection">
4423 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4424</div>
4425<div class="doc_text">
4426
4427<h5>Syntax:</h5>
4428<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4429 &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]4430</pre>
4431
4432<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4433<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4434 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4435
4436<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4437<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
4438 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4439 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4440 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4441 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442
4443<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4444<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4445 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4446 towards zero) unsigned integer value. If the value cannot fit
4447 in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449<h5>Example:</h5>
4450<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4451 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4452 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4453 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4456</div>
4457
4458<!-- _______________________________________________________________________ -->
4459<div class="doc_subsubsection">
4460 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4461</div>
4462<div class="doc_text">
4463
4464<h5>Syntax:</h5>
4465<pre>
4466 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4467</pre>
4468
4469<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4470<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4471 <a href="#t_floating">floating point</a> <tt>value</tt> to
4472 type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4475<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
4476 scalar or vector <a href="#t_floating">floating point</a> value, and a type
4477 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4478 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4479 vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480
4481<h5>Semantics:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4482<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4483 <a href="#t_floating">floating point</a> operand into the nearest (rounding
4484 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4485 the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4487<h5>Example:</h5>
4488<pre>
4489 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4490 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greif463c9342009-10-28 09:21:30 +0000[diff] [blame]4491 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4492</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4494</div>
4495
4496<!-- _______________________________________________________________________ -->
4497<div class="doc_subsubsection">
4498 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4499</div>
4500<div class="doc_text">
4501
4502<h5>Syntax:</h5>
4503<pre>
4504 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4505</pre>
4506
4507<h5>Overview:</h5>
4508<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4509 integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4512<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]4513 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4514 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4515 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4516 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4517
4518<h5>Semantics:</h5>
4519<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4520 integer quantity and converts it to the corresponding floating point
4521 value. If the value cannot fit in the floating point value, the results are
4522 undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4524<h5>Example:</h5>
4525<pre>
4526 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4527 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4528</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4530</div>
4531
4532<!-- _______________________________________________________________________ -->
4533<div class="doc_subsubsection">
4534 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4535</div>
4536<div class="doc_text">
4537
4538<h5>Syntax:</h5>
4539<pre>
4540 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4541</pre>
4542
4543<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4544<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
4545 and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4546
4547<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4548<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]4549 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
4550 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4551 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4552 floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4553
4554<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4555<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
4556 quantity and converts it to the corresponding floating point value. If the
4557 value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4558
4559<h5>Example:</h5>
4560<pre>
4561 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4562 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4563</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4565</div>
4566
4567<!-- _______________________________________________________________________ -->
4568<div class="doc_subsubsection">
4569 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4570</div>
4571<div class="doc_text">
4572
4573<h5>Syntax:</h5>
4574<pre>
4575 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4576</pre>
4577
4578<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4579<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4580 the integer type <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4581
4582<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4583<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4584 must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
4585 <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]4586
4587<h5>Semantics:</h5>
4588<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4589 <tt>ty2</tt> by interpreting the pointer value as an integer and either
4590 truncating or zero extending that value to the size of the integer type. If
4591 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4592 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4593 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4594 change.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4595
4596<h5>Example:</h5>
4597<pre>
4598 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4599 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4600</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602</div>
4603
4604<!-- _______________________________________________________________________ -->
4605<div class="doc_subsubsection">
4606 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4607</div>
4608<div class="doc_text">
4609
4610<h5>Syntax:</h5>
4611<pre>
4612 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4613</pre>
4614
4615<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4616<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
4617 pointer type, <tt>ty2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4618
4619<h5>Arguments:</h5>
4620<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4621 value to cast, and a type to cast it to, which must be a
4622 <a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4623
4624<h5>Semantics:</h5>
4625<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4626 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
4627 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4628 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
4629 than the size of a pointer then a zero extension is done. If they are the
4630 same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4631
4632<h5>Example:</h5>
4633<pre>
4634 %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]4635 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4636 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4637</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4638
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4639</div>
4640
4641<!-- _______________________________________________________________________ -->
4642<div class="doc_subsubsection">
4643 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4644</div>
4645<div class="doc_text">
4646
4647<h5>Syntax:</h5>
4648<pre>
4649 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4650</pre>
4651
4652<h5>Overview:</h5>
4653<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4654 <tt>ty2</tt> without changing any bits.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4655
4656<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4657<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
4658 non-aggregate first class value, and a type to cast it to, which must also be
4659 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
4660 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
4661 identical. If the source type is a pointer, the destination type must also be
4662 a pointer. This instruction supports bitwise conversion of vectors to
4663 integers and to vectors of other types (as long as they have the same
4664 size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4665
4666<h5>Semantics:</h5>
4667<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4668 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4669 this conversion. The conversion is done as if the <tt>value</tt> had been
4670 stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
4671 be converted to other pointer types with this instruction. To convert
4672 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
4673 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4674
4675<h5>Example:</h5>
4676<pre>
4677 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4678 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4679 %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]4680</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4682</div>
4683
4684<!-- ======================================================================= -->
4685<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4687<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4688
4689<p>The instructions in this category are the "miscellaneous" instructions, which
4690 defy better classification.</p>
4691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4692</div>
4693
4694<!-- _______________________________________________________________________ -->
4695<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4696</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4698<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4700<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4701<pre>
4702 &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]4703</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4705<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4706<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
4707 boolean values based on comparison of its two integer, integer vector, or
4708 pointer operands.</p>
4709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4710<h5>Arguments:</h5>
4711<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4712 the condition code indicating the kind of comparison to perform. It is not a
4713 value, just a keyword. The possible condition code are:</p>
4714
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4715<ol>
4716 <li><tt>eq</tt>: equal</li>
4717 <li><tt>ne</tt>: not equal </li>
4718 <li><tt>ugt</tt>: unsigned greater than</li>
4719 <li><tt>uge</tt>: unsigned greater or equal</li>
4720 <li><tt>ult</tt>: unsigned less than</li>
4721 <li><tt>ule</tt>: unsigned less or equal</li>
4722 <li><tt>sgt</tt>: signed greater than</li>
4723 <li><tt>sge</tt>: signed greater or equal</li>
4724 <li><tt>slt</tt>: signed less than</li>
4725 <li><tt>sle</tt>: signed less or equal</li>
4726</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4728<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4729 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
4730 typed. They must also be identical types.</p>
4731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4732<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4733<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
4734 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4735 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]4736 result, as follows:</p>
4737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738<ol>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4739 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4740 <tt>false</tt> otherwise. No sign interpretation is necessary or
4741 performed.</li>
4742
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4743 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4744 <tt>false</tt> otherwise. No sign interpretation is necessary or
4745 performed.</li>
4746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4747 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4748 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4750 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4751 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4752 to <tt>op2</tt>.</li>
4753
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4754 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4755 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4758 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4759
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4760 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4761 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4764 <tt>true</tt> if <tt>op1</tt> is greater than or equal
4765 to <tt>op2</tt>.</li>
4766
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4767 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4768 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
4769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4770 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4771 <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]4772</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4774<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4775 values are compared as if they were integers.</p>
4776
4777<p>If the operands are integer vectors, then they are compared element by
4778 element. The result is an <tt>i1</tt> vector with the same number of elements
4779 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4780
4781<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4782<pre>
4783 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4784 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4785 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4786 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4787 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4788 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4789</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4790
4791<p>Note that the code generator does not yet support vector types with
4792 the <tt>icmp</tt> instruction.</p>
4793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4794</div>
4795
4796<!-- _______________________________________________________________________ -->
4797<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4798</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4800<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4802<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4803<pre>
4804 &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]4805</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4807<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4808<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
4809 values based on comparison of its operands.</p>
4810
4811<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]4812(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4813
4814<p>If the operands are floating point vectors, then the result type is a vector
4815 of boolean with the same number of elements as the operands being
4816 compared.</p>
4817
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4818<h5>Arguments:</h5>
4819<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4820 the condition code indicating the kind of comparison to perform. It is not a
4821 value, just a keyword. The possible condition code are:</p>
4822
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4823<ol>
4824 <li><tt>false</tt>: no comparison, always returns false</li>
4825 <li><tt>oeq</tt>: ordered and equal</li>
4826 <li><tt>ogt</tt>: ordered and greater than </li>
4827 <li><tt>oge</tt>: ordered and greater than or equal</li>
4828 <li><tt>olt</tt>: ordered and less than </li>
4829 <li><tt>ole</tt>: ordered and less than or equal</li>
4830 <li><tt>one</tt>: ordered and not equal</li>
4831 <li><tt>ord</tt>: ordered (no nans)</li>
4832 <li><tt>ueq</tt>: unordered or equal</li>
4833 <li><tt>ugt</tt>: unordered or greater than </li>
4834 <li><tt>uge</tt>: unordered or greater than or equal</li>
4835 <li><tt>ult</tt>: unordered or less than </li>
4836 <li><tt>ule</tt>: unordered or less than or equal</li>
4837 <li><tt>une</tt>: unordered or not equal</li>
4838 <li><tt>uno</tt>: unordered (either nans)</li>
4839 <li><tt>true</tt>: no comparison, always returns true</li>
4840</ol>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4842<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4843 <i>unordered</i> means that either operand may be a QNAN.</p>
4844
4845<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
4846 a <a href="#t_floating">floating point</a> type or
4847 a <a href="#t_vector">vector</a> of floating point type. They must have
4848 identical types.</p>
4849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4850<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4851<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4852 according to the condition code given as <tt>cond</tt>. If the operands are
4853 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky244cf482009-09-27 00:45:11 +0000[diff] [blame]4854 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4855 follows:</p>
4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857<ol>
4858 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4859
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4860 <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]4861 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4862
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863 <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]4864 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
4865
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4866 <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]4867 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4868
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4869 <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]4870 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4871
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4872 <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]4873 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4874
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4875 <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]4876 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4877
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4878 <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]4879
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4880 <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]4881 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
4882
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4883 <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]4884 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
4885
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4886 <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]4887 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
4888
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4889 <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]4890 <tt>op1</tt> is less than <tt>op2</tt>.</li>
4891
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4892 <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]4893 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
4894
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]4895 <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]4896 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
4897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4898 <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]4899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4900 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4901</ol>
4902
4903<h5>Example:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4904<pre>
4905 &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]4906 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4907 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4908 &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]4909</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4910
4911<p>Note that the code generator does not yet support vector types with
4912 the <tt>fcmp</tt> instruction.</p>
4913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4914</div>
4915
4916<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4917<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4918 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4919</div>
4920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4922
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4923<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4924<pre>
4925 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
4926</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4927
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4928<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4929<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
4930 SSA graph representing the function.</p>
4931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4932<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4933<p>The type of the incoming values is specified with the first type field. After
4934 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
4935 one pair for each predecessor basic block of the current block. Only values
4936 of <a href="#t_firstclass">first class</a> type may be used as the value
4937 arguments to the PHI node. Only labels may be used as the label
4938 arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4939
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4940<p>There must be no non-phi instructions between the start of a basic block and
4941 the PHI instructions: i.e. PHI instructions must be first in a basic
4942 block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4943
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4944<p>For the purposes of the SSA form, the use of each incoming value is deemed to
4945 occur on the edge from the corresponding predecessor block to the current
4946 block (but after any definition of an '<tt>invoke</tt>' instruction's return
4947 value on the same edge).</p>
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4948
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4949<h5>Semantics:</h5>
4950<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4951 specified by the pair corresponding to the predecessor basic block that
4952 executed just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4954<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4955<pre>
4956Loop: ; Infinite loop that counts from 0 on up...
4957 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4958 %nextindvar = add i32 %indvar, 1
4959 br label %Loop
4960</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4961
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4962</div>
4963
4964<!-- _______________________________________________________________________ -->
4965<div class="doc_subsubsection">
4966 <a name="i_select">'<tt>select</tt>' Instruction</a>
4967</div>
4968
4969<div class="doc_text">
4970
4971<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4972<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4973 &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>
4974
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4975 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4976</pre>
4977
4978<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4979<p>The '<tt>select</tt>' instruction is used to choose one value based on a
4980 condition, without branching.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4981
4982
4983<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4984<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
4985 values indicating the condition, and two values of the
4986 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
4987 vectors and the condition is a scalar, then entire vectors are selected, not
4988 individual elements.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4989
4990<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4991<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
4992 first value argument; otherwise, it returns the second value argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4993
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]4994<p>If the condition is a vector of i1, then the value arguments must be vectors
4995 of the same size, and the selection is done element by element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4996
4997<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4998<pre>
4999 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
5000</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]5001
5002<p>Note that the code generator does not yet support conditions
5003 with vector type.</p>
5004
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5005</div>
5006
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5007<!-- _______________________________________________________________________ -->
5008<div class="doc_subsubsection">
5009 <a name="i_call">'<tt>call</tt>' Instruction</a>
5010</div>
5011
5012<div class="doc_text">
5013
5014<h5>Syntax:</h5>
5015<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]5016 &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]5017</pre>
5018
5019<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5020<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
5021
5022<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5023<p>This instruction requires several arguments:</p>
5024
5025<ol>
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5026 <li>The optional "tail" marker indicates that the callee function does not
5027 access any allocas or varargs in the caller. Note that calls may be
5028 marked "tail" even if they do not occur before
5029 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
5030 present, the function call is eligible for tail call optimization,
5031 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
5032 optimized into a jump</a>. As of this writing, the extra requirements for
5033 a call to actually be optimized are:
5034 <ul>
5035 <li>Caller and callee both have the calling
5036 convention <tt>fastcc</tt>.</li>
5037 <li>The call is in tail position (ret immediately follows call and ret
5038 uses value of call or is void).</li>
5039 <li>Option <tt>-tailcallopt</tt> is enabled,
5040 or <code>llvm::PerformTailCallOpt</code> is <code>true</code>.</li>
5041 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
5042 constraints are met.</a></li>
5043 </ul>
5044 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5045
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5046 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
5047 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskin3e1a3a02010-01-09 19:44:16 +0000[diff] [blame]5048 defaults to using C calling conventions. The calling convention of the
5049 call must match the calling convention of the target function, or else the
5050 behavior is undefined.</li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5051
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5052 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
5053 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
5054 '<tt>inreg</tt>' attributes are valid here.</li>
5055
5056 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
5057 type of the return value. Functions that return no value are marked
5058 <tt><a href="#t_void">void</a></tt>.</li>
5059
5060 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
5061 being invoked. The argument types must match the types implied by this
5062 signature. This type can be omitted if the function is not varargs and if
5063 the function type does not return a pointer to a function.</li>
5064
5065 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
5066 be invoked. In most cases, this is a direct function invocation, but
5067 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
5068 to function value.</li>
5069
5070 <li>'<tt>function args</tt>': argument list whose types match the function
5071 signature argument types. All arguments must be of
5072 <a href="#t_firstclass">first class</a> type. If the function signature
5073 indicates the function accepts a variable number of arguments, the extra
5074 arguments can be specified.</li>
5075
5076 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
5077 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
5078 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079</ol>
5080
5081<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5082<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
5083 a specified function, with its incoming arguments bound to the specified
5084 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
5085 function, control flow continues with the instruction after the function
5086 call, and the return value of the function is bound to the result
5087 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5088
5089<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5090<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]5091 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]5092 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
5093 %X = tail call i32 @foo() <i>; yields i32</i>
5094 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
5095 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]5096
5097 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]5098 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]5099 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
5100 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]5101 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]5102 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5103</pre>
5104
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5105<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen4730cd32009-09-25 17:04:42 +0000[diff] [blame]5106standard C99 library as being the C99 library functions, and may perform
5107optimizations or generate code for them under that assumption. This is
5108something we'd like to change in the future to provide better support for
5109freestanding environments and non-C-based langauges.</p>
Dale Johannesen9fcf4a92009-09-24 18:38:21 +0000[diff] [blame]5110
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5111</div>
5112
5113<!-- _______________________________________________________________________ -->
5114<div class="doc_subsubsection">
5115 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
5116</div>
5117
5118<div class="doc_text">
5119
5120<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5121<pre>
5122 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
5123</pre>
5124
5125<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5126<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5127 the "variable argument" area of a function call. It is used to implement the
5128 <tt>va_arg</tt> macro in C.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5129
5130<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5131<p>This instruction takes a <tt>va_list*</tt> value and the type of the
5132 argument. It returns a value of the specified argument type and increments
5133 the <tt>va_list</tt> to point to the next argument. The actual type
5134 of <tt>va_list</tt> is target specific.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5135
5136<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5137<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
5138 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
5139 to the next argument. For more information, see the variable argument
5140 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5141
5142<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]5143 take a variable number of arguments, for example, the <tt>vfprintf</tt>
5144 function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5145
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5146<p><tt>va_arg</tt> is an LLVM instruction instead of
5147 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
5148 argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5149
5150<h5>Example:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5151<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
5152
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5153<p>Note that the code generator does not yet fully support va_arg on many
5154 targets. Also, it does not currently support va_arg with aggregate types on
5155 any target.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]5156
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5157</div>
5158
5159<!-- *********************************************************************** -->
5160<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
5161<!-- *********************************************************************** -->
5162
5163<div class="doc_text">
5164
5165<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5166 well known names and semantics and are required to follow certain
5167 restrictions. Overall, these intrinsics represent an extension mechanism for
5168 the LLVM language that does not require changing all of the transformations
5169 in LLVM when adding to the language (or the bitcode reader/writer, the
5170 parser, etc...).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5171
5172<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5173 prefix is reserved in LLVM for intrinsic names; thus, function names may not
5174 begin with this prefix. Intrinsic functions must always be external
5175 functions: you cannot define the body of intrinsic functions. Intrinsic
5176 functions may only be used in call or invoke instructions: it is illegal to
5177 take the address of an intrinsic function. Additionally, because intrinsic
5178 functions are part of the LLVM language, it is required if any are added that
5179 they be documented here.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5180
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5181<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
5182 family of functions that perform the same operation but on different data
5183 types. Because LLVM can represent over 8 million different integer types,
5184 overloading is used commonly to allow an intrinsic function to operate on any
5185 integer type. One or more of the argument types or the result type can be
5186 overloaded to accept any integer type. Argument types may also be defined as
5187 exactly matching a previous argument's type or the result type. This allows
5188 an intrinsic function which accepts multiple arguments, but needs all of them
5189 to be of the same type, to only be overloaded with respect to a single
5190 argument or the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5191
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5192<p>Overloaded intrinsics will have the names of its overloaded argument types
5193 encoded into its function name, each preceded by a period. Only those types
5194 which are overloaded result in a name suffix. Arguments whose type is matched
5195 against another type do not. For example, the <tt>llvm.ctpop</tt> function
5196 can take an integer of any width and returns an integer of exactly the same
5197 integer width. This leads to a family of functions such as
5198 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
5199 %val)</tt>. Only one type, the return type, is overloaded, and only one type
5200 suffix is required. Because the argument's type is matched against the return
5201 type, it does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]5203<p>To learn how to add an intrinsic function, please see the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5204 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5205
5206</div>
5207
5208<!-- ======================================================================= -->
5209<div class="doc_subsection">
5210 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
5211</div>
5212
5213<div class="doc_text">
5214
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5215<p>Variable argument support is defined in LLVM with
5216 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
5217 intrinsic functions. These functions are related to the similarly named
5218 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5219
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5220<p>All of these functions operate on arguments that use a target-specific value
5221 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
5222 not define what this type is, so all transformations should be prepared to
5223 handle these functions regardless of the type used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5224
5225<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]5226 instruction and the variable argument handling intrinsic functions are
5227 used.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5228
5229<div class="doc_code">
5230<pre>
5231define i32 @test(i32 %X, ...) {
5232 ; Initialize variable argument processing
5233 %ap = alloca i8*
5234 %ap2 = bitcast i8** %ap to i8*
5235 call void @llvm.va_start(i8* %ap2)
5236
5237 ; Read a single integer argument
5238 %tmp = va_arg i8** %ap, i32
5239
5240 ; Demonstrate usage of llvm.va_copy and llvm.va_end
5241 %aq = alloca i8*
5242 %aq2 = bitcast i8** %aq to i8*
5243 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
5244 call void @llvm.va_end(i8* %aq2)
5245
5246 ; Stop processing of arguments.
5247 call void @llvm.va_end(i8* %ap2)
5248 ret i32 %tmp
5249}
5250
5251declare void @llvm.va_start(i8*)
5252declare void @llvm.va_copy(i8*, i8*)
5253declare void @llvm.va_end(i8*)
5254</pre>
5255</div>
5256
5257</div>
5258
5259<!-- _______________________________________________________________________ -->
5260<div class="doc_subsubsection">
5261 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
5262</div>
5263
5264
5265<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5266
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5267<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5268<pre>
5269 declare void %llvm.va_start(i8* &lt;arglist&gt;)
5270</pre>
5271
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5272<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5273<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
5274 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]5275
5276<h5>Arguments:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5277<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]5278
5279<h5>Semantics:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5280<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]5281 macro available in C. In a target-dependent way, it initializes
5282 the <tt>va_list</tt> element to which the argument points, so that the next
5283 call to <tt>va_arg</tt> will produce the first variable argument passed to
5284 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
5285 need to know the last argument of the function as the compiler can figure
5286 that out.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5287
5288</div>
5289
5290<!-- _______________________________________________________________________ -->
5291<div class="doc_subsubsection">
5292 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
5293</div>
5294
5295<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5296
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5297<h5>Syntax:</h5>
5298<pre>
5299 declare void @llvm.va_end(i8* &lt;arglist&gt;)
5300</pre>
5301
5302<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5303<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5304 which has been initialized previously
5305 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5306 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5307
5308<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5309<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5310
5311<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5312<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]5313 macro available in C. In a target-dependent way, it destroys
5314 the <tt>va_list</tt> element to which the argument points. Calls
5315 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
5316 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
5317 with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318
5319</div>
5320
5321<!-- _______________________________________________________________________ -->
5322<div class="doc_subsubsection">
5323 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5324</div>
5325
5326<div class="doc_text">
5327
5328<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5329<pre>
5330 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5331</pre>
5332
5333<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5334<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5335 from the source argument list to the destination argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5336
5337<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5338<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5339 The second argument is a pointer to a <tt>va_list</tt> element to copy
5340 from.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5341
5342<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5343<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]5344 macro available in C. In a target-dependent way, it copies the
5345 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
5346 element. This intrinsic is necessary because
5347 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
5348 arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5349
5350</div>
5351
5352<!-- ======================================================================= -->
5353<div class="doc_subsection">
5354 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5355</div>
5356
5357<div class="doc_text">
5358
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5359<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5360Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5361intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
5362roots on the stack</a>, as well as garbage collector implementations that
5363require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
5364barriers. Front-ends for type-safe garbage collected languages should generate
5365these intrinsics to make use of the LLVM garbage collectors. For more details,
5366see <a href="GarbageCollection.html">Accurate Garbage Collection with
5367LLVM</a>.</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5368
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5369<p>The garbage collection intrinsics only operate on objects in the generic
5370 address space (address space zero).</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5372</div>
5373
5374<!-- _______________________________________________________________________ -->
5375<div class="doc_subsubsection">
5376 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5377</div>
5378
5379<div class="doc_text">
5380
5381<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5382<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5383 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5384</pre>
5385
5386<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5387<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]5388 the code generator, and allows some metadata to be associated with it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5389
5390<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5391<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5392 root pointer. The second pointer (which must be either a constant or a
5393 global value address) contains the meta-data to be associated with the
5394 root.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395
5396<h5>Semantics:</h5>
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5397<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]5398 location. At compile-time, the code generator generates information to allow
5399 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5400 intrinsic may only be used in a function which <a href="#gc">specifies a GC
5401 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5402
5403</div>
5404
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5405<!-- _______________________________________________________________________ -->
5406<div class="doc_subsubsection">
5407 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5408</div>
5409
5410<div class="doc_text">
5411
5412<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5413<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5414 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5415</pre>
5416
5417<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5418<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5419 locations, allowing garbage collector implementations that require read
5420 barriers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5421
5422<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5423<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]5424 allocated from the garbage collector. The first object is a pointer to the
5425 start of the referenced object, if needed by the language runtime (otherwise
5426 null).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5427
5428<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5429<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5430 instruction, but may be replaced with substantially more complex code by the
5431 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5432 may only be used in a function which <a href="#gc">specifies a GC
5433 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5434
5435</div>
5436
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5437<!-- _______________________________________________________________________ -->
5438<div class="doc_subsubsection">
5439 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5440</div>
5441
5442<div class="doc_text">
5443
5444<h5>Syntax:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5445<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5446 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5447</pre>
5448
5449<h5>Overview:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5451 locations, allowing garbage collector implementations that require write
5452 barriers (such as generational or reference counting collectors).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5453
5454<h5>Arguments:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455<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]5456 object to store it to, and the third is the address of the field of Obj to
5457 store to. If the runtime does not require a pointer to the object, Obj may
5458 be null.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5459
5460<h5>Semantics:</h5>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5462 instruction, but may be replaced with substantially more complex code by the
5463 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5464 may only be used in a function which <a href="#gc">specifies a GC
5465 algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5466
5467</div>
5468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5469<!-- ======================================================================= -->
5470<div class="doc_subsection">
5471 <a name="int_codegen">Code Generator Intrinsics</a>
5472</div>
5473
5474<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5475
5476<p>These intrinsics are provided by LLVM to expose special features that may
5477 only be implemented with code generator support.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5478
5479</div>
5480
5481<!-- _______________________________________________________________________ -->
5482<div class="doc_subsubsection">
5483 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5484</div>
5485
5486<div class="doc_text">
5487
5488<h5>Syntax:</h5>
5489<pre>
5490 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5491</pre>
5492
5493<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5494<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5495 target-specific value indicating the return address of the current function
5496 or one of its callers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5497
5498<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5499<p>The argument to this intrinsic indicates which function to return the address
5500 for. Zero indicates the calling function, one indicates its caller, etc.
5501 The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5502
5503<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5504<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
5505 indicating the return address of the specified call frame, or zero if it
5506 cannot be identified. The value returned by this intrinsic is likely to be
5507 incorrect or 0 for arguments other than zero, so it should only be used for
5508 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5509
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5510<p>Note that calling this intrinsic does not prevent function inlining or other
5511 aggressive transformations, so the value returned may not be that of the
5512 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514</div>
5515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516<!-- _______________________________________________________________________ -->
5517<div class="doc_subsubsection">
5518 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5519</div>
5520
5521<div class="doc_text">
5522
5523<h5>Syntax:</h5>
5524<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5525 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5526</pre>
5527
5528<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5529<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5530 target-specific frame pointer value for the specified stack frame.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5531
5532<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5533<p>The argument to this intrinsic indicates which function to return the frame
5534 pointer for. Zero indicates the calling function, one indicates its caller,
5535 etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5536
5537<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5538<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
5539 indicating the frame address of the specified call frame, or zero if it
5540 cannot be identified. The value returned by this intrinsic is likely to be
5541 incorrect or 0 for arguments other than zero, so it should only be used for
5542 debugging purposes.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5543
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5544<p>Note that calling this intrinsic does not prevent function inlining or other
5545 aggressive transformations, so the value returned may not be that of the
5546 obvious source-language caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5547
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5548</div>
5549
5550<!-- _______________________________________________________________________ -->
5551<div class="doc_subsubsection">
5552 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5553</div>
5554
5555<div class="doc_text">
5556
5557<h5>Syntax:</h5>
5558<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5559 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5560</pre>
5561
5562<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5563<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
5564 of the function stack, for use
5565 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
5566 useful for implementing language features like scoped automatic variable
5567 sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5568
5569<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5570<p>This intrinsic returns a opaque pointer value that can be passed
5571 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
5572 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
5573 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
5574 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
5575 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
5576 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5577
5578</div>
5579
5580<!-- _______________________________________________________________________ -->
5581<div class="doc_subsubsection">
5582 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5583</div>
5584
5585<div class="doc_text">
5586
5587<h5>Syntax:</h5>
5588<pre>
5589 declare void @llvm.stackrestore(i8 * %ptr)
5590</pre>
5591
5592<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5593<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5594 the function stack to the state it was in when the
5595 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
5596 executed. This is useful for implementing language features like scoped
5597 automatic variable sized arrays in C99.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5598
5599<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5600<p>See the description
5601 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5602
5603</div>
5604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5605<!-- _______________________________________________________________________ -->
5606<div class="doc_subsubsection">
5607 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5608</div>
5609
5610<div class="doc_text">
5611
5612<h5>Syntax:</h5>
5613<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5614 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]5615</pre>
5616
5617<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5618<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
5619 insert a prefetch instruction if supported; otherwise, it is a noop.
5620 Prefetches have no effect on the behavior of the program but can change its
5621 performance characteristics.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622
5623<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5624<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
5625 specifier determining if the fetch should be for a read (0) or write (1),
5626 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5627 locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
5628 and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5629
5630<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5631<p>This intrinsic does not modify the behavior of the program. In particular,
5632 prefetches cannot trap and do not produce a value. On targets that support
5633 this intrinsic, the prefetch can provide hints to the processor cache for
5634 better performance.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5635
5636</div>
5637
5638<!-- _______________________________________________________________________ -->
5639<div class="doc_subsubsection">
5640 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5641</div>
5642
5643<div class="doc_text">
5644
5645<h5>Syntax:</h5>
5646<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5647 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5648</pre>
5649
5650<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5651<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
5652 Counter (PC) in a region of code to simulators and other tools. The method
5653 is target specific, but it is expected that the marker will use exported
5654 symbols to transmit the PC of the marker. The marker makes no guarantees
5655 that it will remain with any specific instruction after optimizations. It is
5656 possible that the presence of a marker will inhibit optimizations. The
5657 intended use is to be inserted after optimizations to allow correlations of
5658 simulation runs.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5659
5660<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5661<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5662
5663<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5664<p>This intrinsic does not modify the behavior of the program. Backends that do
5665 not support this intrinisic may ignore it.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666
5667</div>
5668
5669<!-- _______________________________________________________________________ -->
5670<div class="doc_subsubsection">
5671 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5672</div>
5673
5674<div class="doc_text">
5675
5676<h5>Syntax:</h5>
5677<pre>
5678 declare i64 @llvm.readcyclecounter( )
5679</pre>
5680
5681<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5682<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5683 counter register (or similar low latency, high accuracy clocks) on those
5684 targets that support it. On X86, it should map to RDTSC. On Alpha, it
5685 should map to RPCC. As the backing counters overflow quickly (on the order
5686 of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5687
5688<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5689<p>When directly supported, reading the cycle counter should not modify any
5690 memory. Implementations are allowed to either return a application specific
5691 value or a system wide value. On backends without support, this is lowered
5692 to a constant 0.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693
5694</div>
5695
5696<!-- ======================================================================= -->
5697<div class="doc_subsection">
5698 <a name="int_libc">Standard C Library Intrinsics</a>
5699</div>
5700
5701<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5702
5703<p>LLVM provides intrinsics for a few important standard C library functions.
5704 These intrinsics allow source-language front-ends to pass information about
5705 the alignment of the pointer arguments to the code generator, providing
5706 opportunity for more efficient code generation.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5707
5708</div>
5709
5710<!-- _______________________________________________________________________ -->
5711<div class="doc_subsubsection">
5712 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5713</div>
5714
5715<div class="doc_text">
5716
5717<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5718<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
5719 integer bit width. Not all targets support all bit widths however.</p>
5720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5721<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5722 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5723 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5724 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5725 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5726 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5727 i32 &lt;len&gt;, i32 &lt;align&gt;)
5728 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5729 i64 &lt;len&gt;, i32 &lt;align&gt;)
5730</pre>
5731
5732<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5733<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5734 source location to the destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5735
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5736<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5737 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5738
5739<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5740<p>The first argument is a pointer to the destination, the second is a pointer
5741 to the source. The third argument is an integer argument specifying the
5742 number of bytes to copy, and the fourth argument is the alignment of the
5743 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5744
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5745<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5746 then the caller guarantees that both the source and destination pointers are
5747 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5748
5749<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5750<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
5751 source location to the destination location, which are not allowed to
5752 overlap. It copies "len" bytes of memory over. If the argument is known to
5753 be aligned to some boundary, this can be specified as the fourth argument,
5754 otherwise it should be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5756</div>
5757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5758<!-- _______________________________________________________________________ -->
5759<div class="doc_subsubsection">
5760 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5761</div>
5762
5763<div class="doc_text">
5764
5765<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5766<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]5767 width. Not all targets support all bit widths however.</p>
5768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5769<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5770 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5771 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5772 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5773 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5774 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5775 i32 &lt;len&gt;, i32 &lt;align&gt;)
5776 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5777 i64 &lt;len&gt;, i32 &lt;align&gt;)
5778</pre>
5779
5780<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5781<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
5782 source location to the destination location. It is similar to the
5783 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
5784 overlap.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5785
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5786<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5787 intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5788
5789<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5790<p>The first argument is a pointer to the destination, the second is a pointer
5791 to the source. The third argument is an integer argument specifying the
5792 number of bytes to copy, and the fourth argument is the alignment of the
5793 source and destination locations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5794
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5795<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5796 then the caller guarantees that the source and destination pointers are
5797 aligned to that boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798
5799<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5800<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
5801 source location to the destination location, which may overlap. It copies
5802 "len" bytes of memory over. If the argument is known to be aligned to some
5803 boundary, this can be specified as the fourth argument, otherwise it should
5804 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806</div>
5807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5808<!-- _______________________________________________________________________ -->
5809<div class="doc_subsubsection">
5810 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5811</div>
5812
5813<div class="doc_text">
5814
5815<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5816<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]5817 width. Not all targets support all bit widths however.</p>
5818
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5819<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5820 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5821 i8 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5822 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5823 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5824 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5825 i32 &lt;len&gt;, i32 &lt;align&gt;)
5826 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5827 i64 &lt;len&gt;, i32 &lt;align&gt;)
5828</pre>
5829
5830<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5831<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
5832 particular byte value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5833
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5834<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
5835 intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836
5837<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5838<p>The first argument is a pointer to the destination to fill, the second is the
5839 byte value to fill it with, the third argument is an integer argument
5840 specifying the number of bytes to fill, and the fourth argument is the known
5841 alignment of destination location.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5843<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
5844 then the caller guarantees that the destination pointer is aligned to that
5845 boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5846
5847<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5848<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
5849 at the destination location. If the argument is known to be aligned to some
5850 boundary, this can be specified as the fourth argument, otherwise it should
5851 be set to 0 or 1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5853</div>
5854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5855<!-- _______________________________________________________________________ -->
5856<div class="doc_subsubsection">
5857 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5858</div>
5859
5860<div class="doc_text">
5861
5862<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5863<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
5864 floating point or vector of floating point type. Not all targets support all
5865 types however.</p>
5866
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5867<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5868 declare float @llvm.sqrt.f32(float %Val)
5869 declare double @llvm.sqrt.f64(double %Val)
5870 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5871 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5872 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5873</pre>
5874
5875<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5876<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
5877 returning the same value as the libm '<tt>sqrt</tt>' functions would.
5878 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
5879 behavior for negative numbers other than -0.0 (which allows for better
5880 optimization, because there is no need to worry about errno being
5881 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]5882
5883<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5884<p>The argument and return value are floating point numbers of the same
5885 type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5886
5887<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5888<p>This function returns the sqrt of the specified operand if it is a
5889 nonnegative floating point number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5890
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5891</div>
5892
5893<!-- _______________________________________________________________________ -->
5894<div class="doc_subsubsection">
5895 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5896</div>
5897
5898<div class="doc_text">
5899
5900<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5901<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
5902 floating point or vector of floating point type. Not all targets support all
5903 types however.</p>
5904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5905<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5906 declare float @llvm.powi.f32(float %Val, i32 %power)
5907 declare double @llvm.powi.f64(double %Val, i32 %power)
5908 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5909 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5910 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5911</pre>
5912
5913<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5914<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5915 specified (positive or negative) power. The order of evaluation of
5916 multiplications is not defined. When a vector of floating point type is
5917 used, the second argument remains a scalar integer value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5918
5919<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5920<p>The second argument is an integer power, and the first is a value to raise to
5921 that power.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5922
5923<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5924<p>This function returns the first value raised to the second power with an
5925 unspecified sequence of rounding operations.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5927</div>
5928
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5929<!-- _______________________________________________________________________ -->
5930<div class="doc_subsubsection">
5931 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5932</div>
5933
5934<div class="doc_text">
5935
5936<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5937<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5938 floating point or vector of floating point type. Not all targets support all
5939 types however.</p>
5940
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5941<pre>
5942 declare float @llvm.sin.f32(float %Val)
5943 declare double @llvm.sin.f64(double %Val)
5944 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5945 declare fp128 @llvm.sin.f128(fp128 %Val)
5946 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5947</pre>
5948
5949<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5950<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5951
5952<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5953<p>The argument and return value are floating point numbers of the same
5954 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5955
5956<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5957<p>This function returns the sine of the specified operand, returning the same
5958 values as the libm <tt>sin</tt> functions would, and handles error conditions
5959 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5960
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5961</div>
5962
5963<!-- _______________________________________________________________________ -->
5964<div class="doc_subsubsection">
5965 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5966</div>
5967
5968<div class="doc_text">
5969
5970<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5971<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5972 floating point or vector of floating point type. Not all targets support all
5973 types however.</p>
5974
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5975<pre>
5976 declare float @llvm.cos.f32(float %Val)
5977 declare double @llvm.cos.f64(double %Val)
5978 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5979 declare fp128 @llvm.cos.f128(fp128 %Val)
5980 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5981</pre>
5982
5983<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5984<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5985
5986<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5987<p>The argument and return value are floating point numbers of the same
5988 type.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5989
5990<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]5991<p>This function returns the cosine of the specified operand, returning the same
5992 values as the libm <tt>cos</tt> functions would, and handles error conditions
5993 in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5994
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5995</div>
5996
5997<!-- _______________________________________________________________________ -->
5998<div class="doc_subsubsection">
5999 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
6000</div>
6001
6002<div class="doc_text">
6003
6004<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6005<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
6006 floating point or vector of floating point type. Not all targets support all
6007 types however.</p>
6008
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6009<pre>
6010 declare float @llvm.pow.f32(float %Val, float %Power)
6011 declare double @llvm.pow.f64(double %Val, double %Power)
6012 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
6013 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
6014 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
6015</pre>
6016
6017<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6018<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
6019 specified (positive or negative) power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6020
6021<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6022<p>The second argument is a floating point power, and the first is a value to
6023 raise to that power.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6024
6025<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6026<p>This function returns the first value raised to the second power, returning
6027 the same values as the libm <tt>pow</tt> functions would, and handles error
6028 conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6029
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]6030</div>
6031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6032<!-- ======================================================================= -->
6033<div class="doc_subsection">
6034 <a name="int_manip">Bit Manipulation Intrinsics</a>
6035</div>
6036
6037<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6038
6039<p>LLVM provides intrinsics for a few important bit manipulation operations.
6040 These allow efficient code generation for some algorithms.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6041
6042</div>
6043
6044<!-- _______________________________________________________________________ -->
6045<div class="doc_subsubsection">
6046 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
6047</div>
6048
6049<div class="doc_text">
6050
6051<h5>Syntax:</h5>
6052<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6053 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
6054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6055<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6056 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
6057 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
6058 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6059</pre>
6060
6061<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6062<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
6063 values with an even number of bytes (positive multiple of 16 bits). These
6064 are useful for performing operations on data that is not in the target's
6065 native byte order.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6066
6067<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6068<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
6069 and low byte of the input i16 swapped. Similarly,
6070 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
6071 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
6072 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
6073 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
6074 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
6075 more, respectively).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6076
6077</div>
6078
6079<!-- _______________________________________________________________________ -->
6080<div class="doc_subsubsection">
6081 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
6082</div>
6083
6084<div class="doc_text">
6085
6086<h5>Syntax:</h5>
6087<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]6088 width. Not all targets support all bit widths however.</p>
6089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6090<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6091 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6092 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6093 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6094 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
6095 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6096</pre>
6097
6098<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6099<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
6100 in a value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6101
6102<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6103<p>The only argument is the value to be counted. The argument may be of any
6104 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6105
6106<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6107<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]6108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6109</div>
6110
6111<!-- _______________________________________________________________________ -->
6112<div class="doc_subsubsection">
6113 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
6114</div>
6115
6116<div class="doc_text">
6117
6118<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6119<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
6120 integer bit width. Not all targets support all bit widths however.</p>
6121
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6122<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6123 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
6124 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6125 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6126 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
6127 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6128</pre>
6129
6130<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6131<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
6132 leading zeros in a variable.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6133
6134<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6135<p>The only argument is the value to be counted. The argument may be of any
6136 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6137
6138<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6139<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
6140 zeros in a variable. If the src == 0 then the result is the size in bits of
6141 the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6142
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6143</div>
6144
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6145<!-- _______________________________________________________________________ -->
6146<div class="doc_subsubsection">
6147 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6148</div>
6149
6150<div class="doc_text">
6151
6152<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6153<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
6154 integer bit width. Not all targets support all bit widths however.</p>
6155
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6156<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6157 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6158 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6159 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6160 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6161 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6162</pre>
6163
6164<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6165<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6166 trailing zeros.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6167
6168<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6169<p>The only argument is the value to be counted. The argument may be of any
6170 integer type. The return type must match the argument type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6171
6172<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6173<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
6174 zeros in a variable. If the src == 0 then the result is the size in bits of
6175 the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6177</div>
6178
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6179<!-- ======================================================================= -->
6180<div class="doc_subsection">
6181 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6182</div>
6183
6184<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6185
6186<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6187
6188</div>
6189
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6190<!-- _______________________________________________________________________ -->
6191<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6192 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6193</div>
6194
6195<div class="doc_text">
6196
6197<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6198<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]6199 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6200
6201<pre>
6202 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6203 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6204 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6205</pre>
6206
6207<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6208<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6209 a signed addition of the two arguments, and indicate whether an overflow
6210 occurred during the signed summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6211
6212<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6213<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]6214 be of integer types of any bit width, but they must have the same bit
6215 width. The second element of the result structure must be of
6216 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6217 undergo signed addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6218
6219<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6220<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6221 a signed addition of the two variables. They return a structure &mdash; the
6222 first element of which is the signed summation, and the second element of
6223 which is a bit specifying if the signed summation resulted in an
6224 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6225
6226<h5>Examples:</h5>
6227<pre>
6228 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6229 %sum = extractvalue {i32, i1} %res, 0
6230 %obit = extractvalue {i32, i1} %res, 1
6231 br i1 %obit, label %overflow, label %normal
6232</pre>
6233
6234</div>
6235
6236<!-- _______________________________________________________________________ -->
6237<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6238 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6239</div>
6240
6241<div class="doc_text">
6242
6243<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6244<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]6245 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6246
6247<pre>
6248 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6249 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6250 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6251</pre>
6252
6253<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6254<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6255 an unsigned addition of the two arguments, and indicate whether a carry
6256 occurred during the unsigned summation.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6257
6258<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6259<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]6260 be of integer types of any bit width, but they must have the same bit
6261 width. The second element of the result structure must be of
6262 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6263 undergo unsigned addition.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6264
6265<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6266<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6267 an unsigned addition of the two arguments. They return a structure &mdash;
6268 the first element of which is the sum, and the second element of which is a
6269 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6270
6271<h5>Examples:</h5>
6272<pre>
6273 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6274 %sum = extractvalue {i32, i1} %res, 0
6275 %obit = extractvalue {i32, i1} %res, 1
6276 br i1 %obit, label %carry, label %normal
6277</pre>
6278
6279</div>
6280
6281<!-- _______________________________________________________________________ -->
6282<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6283 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6284</div>
6285
6286<div class="doc_text">
6287
6288<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6289<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]6290 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6291
6292<pre>
6293 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6294 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6295 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6296</pre>
6297
6298<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6299<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6300 a signed subtraction of the two arguments, and indicate whether an overflow
6301 occurred during the signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6302
6303<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6304<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]6305 be of integer types of any bit width, but they must have the same bit
6306 width. The second element of the result structure must be of
6307 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6308 undergo signed subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6309
6310<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6311<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6312 a signed subtraction of the two arguments. They return a structure &mdash;
6313 the first element of which is the subtraction, and the second element of
6314 which is a bit specifying if the signed subtraction resulted in an
6315 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6316
6317<h5>Examples:</h5>
6318<pre>
6319 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6320 %sum = extractvalue {i32, i1} %res, 0
6321 %obit = extractvalue {i32, i1} %res, 1
6322 br i1 %obit, label %overflow, label %normal
6323</pre>
6324
6325</div>
6326
6327<!-- _______________________________________________________________________ -->
6328<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6329 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6330</div>
6331
6332<div class="doc_text">
6333
6334<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6335<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]6336 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6337
6338<pre>
6339 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6340 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6341 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6342</pre>
6343
6344<h5>Overview:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6345<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6346 an unsigned subtraction of the two arguments, and indicate whether an
6347 overflow occurred during the unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6348
6349<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6350<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]6351 be of integer types of any bit width, but they must have the same bit
6352 width. The second element of the result structure must be of
6353 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6354 undergo unsigned subtraction.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6355
6356<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6357<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6358 an unsigned subtraction of the two arguments. They return a structure &mdash;
6359 the first element of which is the subtraction, and the second element of
6360 which is a bit specifying if the unsigned subtraction resulted in an
6361 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6362
6363<h5>Examples:</h5>
6364<pre>
6365 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6366 %sum = extractvalue {i32, i1} %res, 0
6367 %obit = extractvalue {i32, i1} %res, 1
6368 br i1 %obit, label %overflow, label %normal
6369</pre>
6370
6371</div>
6372
6373<!-- _______________________________________________________________________ -->
6374<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6375 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6376</div>
6377
6378<div class="doc_text">
6379
6380<h5>Syntax:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6381<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]6382 on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6383
6384<pre>
6385 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6386 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6387 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6388</pre>
6389
6390<h5>Overview:</h5>
6391
6392<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6393 a signed multiplication of the two arguments, and indicate whether an
6394 overflow occurred during the signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6395
6396<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6397<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]6398 be of integer types of any bit width, but they must have the same bit
6399 width. The second element of the result structure must be of
6400 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6401 undergo signed multiplication.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6402
6403<h5>Semantics:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6404<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6405 a signed multiplication of the two arguments. They return a structure &mdash;
6406 the first element of which is the multiplication, and the second element of
6407 which is a bit specifying if the signed multiplication resulted in an
6408 overflow.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6409
6410<h5>Examples:</h5>
6411<pre>
6412 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6413 %sum = extractvalue {i32, i1} %res, 0
6414 %obit = extractvalue {i32, i1} %res, 1
6415 br i1 %obit, label %overflow, label %normal
6416</pre>
6417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6418</div>
6419
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6420<!-- _______________________________________________________________________ -->
6421<div class="doc_subsubsection">
6422 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6423</div>
6424
6425<div class="doc_text">
6426
6427<h5>Syntax:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6428<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]6429 on any integer bit width.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6430
6431<pre>
6432 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6433 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6434 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6435</pre>
6436
6437<h5>Overview:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6438<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6439 a unsigned multiplication of the two arguments, and indicate whether an
6440 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6441
6442<h5>Arguments:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6443<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]6444 be of integer types of any bit width, but they must have the same bit
6445 width. The second element of the result structure must be of
6446 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
6447 undergo unsigned multiplication.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6448
6449<h5>Semantics:</h5>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6450<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6451 an unsigned multiplication of the two arguments. They return a structure
6452 &mdash; the first element of which is the multiplication, and the second
6453 element of which is a bit specifying if the unsigned multiplication resulted
6454 in an overflow.</p>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6455
6456<h5>Examples:</h5>
6457<pre>
6458 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6459 %sum = extractvalue {i32, i1} %res, 0
6460 %obit = extractvalue {i32, i1} %res, 1
6461 br i1 %obit, label %overflow, label %normal
6462</pre>
6463
6464</div>
6465
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6466<!-- ======================================================================= -->
6467<div class="doc_subsection">
6468 <a name="int_debugger">Debugger Intrinsics</a>
6469</div>
6470
6471<div class="doc_text">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6472
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6473<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
6474 prefix), are described in
6475 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
6476 Level Debugging</a> document.</p>
6477
6478</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6479
6480<!-- ======================================================================= -->
6481<div class="doc_subsection">
6482 <a name="int_eh">Exception Handling Intrinsics</a>
6483</div>
6484
6485<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6486
6487<p>The LLVM exception handling intrinsics (which all start with
6488 <tt>llvm.eh.</tt> prefix), are described in
6489 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6490 Handling</a> document.</p>
6491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6492</div>
6493
6494<!-- ======================================================================= -->
6495<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6496 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6497</div>
6498
6499<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6500
6501<p>This intrinsic makes it possible to excise one parameter, marked with
6502 the <tt>nest</tt> attribute, from a function. The result is a callable
6503 function pointer lacking the nest parameter - the caller does not need to
6504 provide a value for it. Instead, the value to use is stored in advance in a
6505 "trampoline", a block of memory usually allocated on the stack, which also
6506 contains code to splice the nest value into the argument list. This is used
6507 to implement the GCC nested function address extension.</p>
6508
6509<p>For example, if the function is
6510 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
6511 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
6512 follows:</p>
6513
6514<div class="doc_code">
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6515<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6516 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6517 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6518 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6519 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6520</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6521</div>
6522
6523<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6524 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
6525
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6526</div>
6527
6528<!-- _______________________________________________________________________ -->
6529<div class="doc_subsubsection">
6530 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6531</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6532
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6533<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6534
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6535<h5>Syntax:</h5>
6536<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6537 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]6538</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6539
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6540<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6541<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
6542 function pointer suitable for executing it.</p>
6543
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6544<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6545<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6546 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
6547 sufficiently aligned block of memory; this memory is written to by the
6548 intrinsic. Note that the size and the alignment are target-specific - LLVM
6549 currently provides no portable way of determining them, so a front-end that
6550 generates this intrinsic needs to have some target-specific knowledge.
6551 The <tt>func</tt> argument must hold a function bitcast to
6552 an <tt>i8*</tt>.</p>
6553
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6554<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6555<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
6556 dependent code, turning it into a function. A pointer to this function is
6557 returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
6558 function pointer type</a> before being called. The new function's signature
6559 is the same as that of <tt>func</tt> with any arguments marked with
6560 the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
6561 is allowed, and it must be of pointer type. Calling the new function is
6562 equivalent to calling <tt>func</tt> with the same argument list, but
6563 with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
6564 calling <tt>llvm.init.trampoline</tt>, the memory pointed to
6565 by <tt>tramp</tt> is modified, then the effect of any later call to the
6566 returned function pointer is undefined.</p>
6567
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6568</div>
6569
6570<!-- ======================================================================= -->
6571<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6572 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6573</div>
6574
6575<div class="doc_text">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6576
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6577<p>These intrinsic functions expand the "universal IR" of LLVM to represent
6578 hardware constructs for atomic operations and memory synchronization. This
6579 provides an interface to the hardware, not an interface to the programmer. It
6580 is aimed at a low enough level to allow any programming models or APIs
6581 (Application Programming Interfaces) which need atomic behaviors to map
6582 cleanly onto it. It is also modeled primarily on hardware behavior. Just as
6583 hardware provides a "universal IR" for source languages, it also provides a
6584 starting point for developing a "universal" atomic operation and
6585 synchronization IR.</p>
6586
6587<p>These do <em>not</em> form an API such as high-level threading libraries,
6588 software transaction memory systems, atomic primitives, and intrinsic
6589 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6590 application libraries. The hardware interface provided by LLVM should allow
6591 a clean implementation of all of these APIs and parallel programming models.
6592 No one model or paradigm should be selected above others unless the hardware
6593 itself ubiquitously does so.</p>
6594
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6595</div>
6596
6597<!-- _______________________________________________________________________ -->
6598<div class="doc_subsubsection">
6599 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6600</div>
6601<div class="doc_text">
6602<h5>Syntax:</h5>
6603<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6604 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]6605</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6606
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6607<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6608<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6609 specific pairs of memory access types.</p>
6610
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6611<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6612<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6613 The first four arguments enables a specific barrier as listed below. The
6614 fith argument specifies that the barrier applies to io or device or uncached
6615 memory.</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6616
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6617<ul>
6618 <li><tt>ll</tt>: load-load barrier</li>
6619 <li><tt>ls</tt>: load-store barrier</li>
6620 <li><tt>sl</tt>: store-load barrier</li>
6621 <li><tt>ss</tt>: store-store barrier</li>
6622 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
6623</ul>
6624
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6625<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6626<p>This intrinsic causes the system to enforce some ordering constraints upon
6627 the loads and stores of the program. This barrier does not
6628 indicate <em>when</em> any events will occur, it only enforces
6629 an <em>order</em> in which they occur. For any of the specified pairs of load
6630 and store operations (f.ex. load-load, or store-load), all of the first
6631 operations preceding the barrier will complete before any of the second
6632 operations succeeding the barrier begin. Specifically the semantics for each
6633 pairing is as follows:</p>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6634
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6635<ul>
6636 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6637 after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6638 <li><tt>ls</tt>: All loads before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6639 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6640 <li><tt>ss</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6641 store after the barrier begins.</li>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6642 <li><tt>sl</tt>: All stores before the barrier must complete before any
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6643 load after the barrier begins.</li>
6644</ul>
6645
6646<p>These semantics are applied with a logical "and" behavior when more than one
6647 is enabled in a single memory barrier intrinsic.</p>
6648
6649<p>Backends may implement stronger barriers than those requested when they do
6650 not support as fine grained a barrier as requested. Some architectures do
6651 not need all types of barriers and on such architectures, these become
6652 noops.</p>
6653
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6654<h5>Example:</h5>
6655<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6656%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6657%ptr = bitcast i8* %mallocP to i32*
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6658 store i32 4, %ptr
6659
6660%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6661 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6662 <i>; guarantee the above finishes</i>
6663 store i32 8, %ptr <i>; before this begins</i>
6664</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6665
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6666</div>
6667
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6668<!-- _______________________________________________________________________ -->
6669<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6670 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6671</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6672
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6673<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6674
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6675<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6676<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6677 any integer bit width and for different address spaces. Not all targets
6678 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6679
6680<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6681 declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6682 declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6683 declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6684 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]6685</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6686
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6687<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6688<p>This loads a value in memory and compares it to a given value. If they are
6689 equal, it stores a new value into the memory.</p>
6690
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6691<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6692<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
6693 as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6694 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6695 this integer type. While any bit width integer may be used, targets may only
6696 lower representations they support in hardware.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6697
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6698<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6699<p>This entire intrinsic must be executed atomically. It first loads the value
6700 in memory pointed to by <tt>ptr</tt> and compares it with the
6701 value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
6702 memory. The loaded value is yielded in all cases. This provides the
6703 equivalent of an atomic compare-and-swap operation within the SSA
6704 framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6705
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6706<h5>Examples:</h5>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]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.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %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.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6720 <i>; yields {i32}:result2 = 8</i>
6721%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6722
6723%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</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">
6730 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6731</div>
6732<div class="doc_text">
6733<h5>Syntax:</h5>
6734
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6735<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6736 integer bit width. Not all targets support all bit widths however.</p>
6737
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6738<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6739 declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6740 declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6741 declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6742 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]6743</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6744
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6745<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6746<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6747 the value from memory. It then stores the value in <tt>val</tt> in the memory
6748 at <tt>ptr</tt>.</p>
6749
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6750<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6751<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
6752 the <tt>val</tt> argument and the result must be integers of the same bit
6753 width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6754 integer type. The targets may only lower integer representations they
6755 support.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]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 loads the value pointed to by <tt>ptr</tt>, yields it, and
6759 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6760 equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6761
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]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*
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6766 store i32 4, %ptr
6767
6768%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6769%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6770 <i>; yields {i32}:result1 = 4</i>
6771%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6772%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6773
6774%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6775%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6776 <i>; yields {i32}:result2 = 8</i>
6777
6778%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6779%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6780</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6781
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6782</div>
6783
6784<!-- _______________________________________________________________________ -->
6785<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6786 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6787
6788</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6789
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6790<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6791
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6792<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6793<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
6794 any integer bit width. Not all targets support all bit widths however.</p>
6795
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6796<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6797 declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6798 declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6799 declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6800 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]6801</pre>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6802
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6803<h5>Overview:</h5>
6804<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
6805 at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6806
6807<h5>Arguments:</h5>
6808<p>The intrinsic takes two arguments, the first a pointer to an integer value
6809 and the second an integer value. The result is also an integer value. These
6810 integer types can have any bit width, but they must all have the same bit
6811 width. The targets may only lower integer representations they support.</p>
6812
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6813<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6814<p>This intrinsic does a series of operations atomically. It first loads the
6815 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6816 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]6817
6818<h5>Examples:</h5>
6819<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6820%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6821%ptr = bitcast i8* %mallocP to i32*
6822 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6823%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6824 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6825%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6826 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6827%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6828 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6829%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6830</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6831
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6832</div>
6833
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6834<!-- _______________________________________________________________________ -->
6835<div class="doc_subsubsection">
6836 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6837
6838</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6839
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6840<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6841
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6842<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6843<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
6844 any integer bit width and for different address spaces. Not all targets
6845 support all bit widths however.</p>
6846
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6847<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6848 declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6849 declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6850 declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6851 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]6852</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6853
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6854<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]6855<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6856 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
6857
6858<h5>Arguments:</h5>
6859<p>The intrinsic takes two arguments, the first a pointer to an integer value
6860 and the second an integer value. The result is also an integer value. These
6861 integer types can have any bit width, but they must all have the same bit
6862 width. The targets may only lower integer representations they support.</p>
6863
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6864<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6865<p>This intrinsic does a series of operations atomically. It first loads the
6866 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6867 result to <tt>ptr</tt>. It yields the original value stored
6868 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6869
6870<h5>Examples:</h5>
6871<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6872%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6873%ptr = bitcast i8* %mallocP to i32*
6874 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6875%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6876 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6877%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6878 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6879%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6880 <i>; yields {i32}:result3 = 2</i>
6881%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6882</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6883
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6884</div>
6885
6886<!-- _______________________________________________________________________ -->
6887<div class="doc_subsubsection">
6888 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6889 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6890 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6891 <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]6892</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6893
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6894<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6895
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6896<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6897<p>These are overloaded intrinsics. You can
6898 use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
6899 <tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
6900 bit width and for different address spaces. Not all targets support all bit
6901 widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6902
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6903<pre>
6904 declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6905 declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6906 declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6907 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]6908</pre>
6909
6910<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6911 declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6912 declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6913 declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6914 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]6915</pre>
6916
6917<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6918 declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6919 declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6920 declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6921 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]6922</pre>
6923
6924<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6925 declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6926 declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6927 declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6928 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]6929</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6930
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6931<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6932<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6933 the value stored in memory at <tt>ptr</tt>. It yields the original value
6934 at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6935
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6936<h5>Arguments:</h5>
6937<p>These intrinsics take two arguments, the first a pointer to an integer value
6938 and the second an integer value. The result is also an integer value. These
6939 integer types can have any bit width, but they must all have the same bit
6940 width. The targets may only lower integer representations they support.</p>
6941
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6942<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6943<p>These intrinsics does a series of operations atomically. They first load the
6944 value stored at <tt>ptr</tt>. They then do the bitwise
6945 operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
6946 original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6947
6948<h5>Examples:</h5>
6949<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]6950%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
6951%ptr = bitcast i8* %mallocP to i32*
6952 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6953%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6954 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6955%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6956 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6957%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6958 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6959%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6960 <i>; yields {i32}:result3 = FF</i>
6961%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6962</pre>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6963
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6964</div>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6965
6966<!-- _______________________________________________________________________ -->
6967<div class="doc_subsubsection">
6968 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6969 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6970 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6971 <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]6972</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6973
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6974<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6975
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6976<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6977<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6978 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
6979 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6980 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6981
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6982<pre>
6983 declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6984 declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6985 declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6986 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]6987</pre>
6988
6989<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6990 declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6991 declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6992 declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6993 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]6994</pre>
6995
6996<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]6997 declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6998 declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6999 declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7000 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]7001</pre>
7002
7003<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7004 declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7005 declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7006 declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7007 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]7008</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7009
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7010<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7011<p>These intrinsics takes the signed or unsigned minimum or maximum of
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7012 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7013 original value at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7014
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7015<h5>Arguments:</h5>
7016<p>These intrinsics take two arguments, the first a pointer to an integer value
7017 and the second an integer value. The result is also an integer value. These
7018 integer types can have any bit width, but they must all have the same bit
7019 width. The targets may only lower integer representations they support.</p>
7020
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7021<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7022<p>These intrinsics does a series of operations atomically. They first load the
7023 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
7024 max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
7025 yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7026
7027<h5>Examples:</h5>
7028<pre>
Victor Hernandez6b054092009-10-26 23:44:29 +0000[diff] [blame]7029%mallocP = tail call i8* @malloc(i32 ptrtoint (i32* getelementptr (i32* null, i32 1) to i32))
7030%ptr = bitcast i8* %mallocP to i32*
7031 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7032%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7033 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7034%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7035 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7036%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7037 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7038%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7039 <i>; yields {i32}:result3 = 8</i>
7040%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7041</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7042
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7043</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7044
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7045
7046<!-- ======================================================================= -->
7047<div class="doc_subsection">
7048 <a name="int_memorymarkers">Memory Use Markers</a>
7049</div>
7050
7051<div class="doc_text">
7052
7053<p>This class of intrinsics exists to information about the lifetime of memory
7054 objects and ranges where variables are immutable.</p>
7055
7056</div>
7057
7058<!-- _______________________________________________________________________ -->
7059<div class="doc_subsubsection">
7060 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
7061</div>
7062
7063<div class="doc_text">
7064
7065<h5>Syntax:</h5>
7066<pre>
7067 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7068</pre>
7069
7070<h5>Overview:</h5>
7071<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
7072 object's lifetime.</p>
7073
7074<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7075<p>The first argument is a constant integer representing the size of the
7076 object, or -1 if it is variable sized. The second argument is a pointer to
7077 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7078
7079<h5>Semantics:</h5>
7080<p>This intrinsic indicates that before this point in the code, the value of the
7081 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]7082 never be used and has an undefined value. A load from the pointer that
7083 precedes this intrinsic can be replaced with
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7084 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
7085
7086</div>
7087
7088<!-- _______________________________________________________________________ -->
7089<div class="doc_subsubsection">
7090 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
7091</div>
7092
7093<div class="doc_text">
7094
7095<h5>Syntax:</h5>
7096<pre>
7097 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7098</pre>
7099
7100<h5>Overview:</h5>
7101<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
7102 object's lifetime.</p>
7103
7104<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7105<p>The first argument is a constant integer representing the size of the
7106 object, or -1 if it is variable sized. The second argument is a pointer to
7107 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7108
7109<h5>Semantics:</h5>
7110<p>This intrinsic indicates that after this point in the code, the value of the
7111 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
7112 never be used and has an undefined value. Any stores into the memory object
7113 following this intrinsic may be removed as dead.
7114
7115</div>
7116
7117<!-- _______________________________________________________________________ -->
7118<div class="doc_subsubsection">
7119 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
7120</div>
7121
7122<div class="doc_text">
7123
7124<h5>Syntax:</h5>
7125<pre>
7126 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;) readonly
7127</pre>
7128
7129<h5>Overview:</h5>
7130<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
7131 a memory object will not change.</p>
7132
7133<h5>Arguments:</h5>
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7134<p>The first argument is a constant integer representing the size of the
7135 object, or -1 if it is variable sized. The second argument is a pointer to
7136 the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7137
7138<h5>Semantics:</h5>
7139<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
7140 the return value, the referenced memory location is constant and
7141 unchanging.</p>
7142
7143</div>
7144
7145<!-- _______________________________________________________________________ -->
7146<div class="doc_subsubsection">
7147 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
7148</div>
7149
7150<div class="doc_text">
7151
7152<h5>Syntax:</h5>
7153<pre>
7154 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
7155</pre>
7156
7157<h5>Overview:</h5>
7158<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
7159 a memory object are mutable.</p>
7160
7161<h5>Arguments:</h5>
7162<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky23f49982009-10-13 07:57:33 +0000[diff] [blame]7163 The second argument is a constant integer representing the size of the
7164 object, or -1 if it is variable sized and the third argument is a pointer
7165 to the object.</p>
Nick Lewyckyc888d352009-10-13 07:03:23 +0000[diff] [blame]7166
7167<h5>Semantics:</h5>
7168<p>This intrinsic indicates that the memory is mutable again.</p>
7169
7170</div>
7171
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7172<!-- ======================================================================= -->
7173<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7174 <a name="int_general">General Intrinsics</a>
7175</div>
7176
7177<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7178
7179<p>This class of intrinsics is designed to be generic and has no specific
7180 purpose.</p>
7181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7182</div>
7183
7184<!-- _______________________________________________________________________ -->
7185<div class="doc_subsubsection">
7186 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7187</div>
7188
7189<div class="doc_text">
7190
7191<h5>Syntax:</h5>
7192<pre>
7193 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7194</pre>
7195
7196<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7197<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7198
7199<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7200<p>The first argument is a pointer to a value, the second is a pointer to a
7201 global string, the third is a pointer to a global string which is the source
7202 file name, and the last argument is the line number.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7203
7204<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7205<p>This intrinsic allows annotation of local variables with arbitrary strings.
7206 This can be useful for special purpose optimizations that want to look for
7207 these annotations. These have no other defined use, they are ignored by code
7208 generation and optimization.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7210</div>
7211
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7212<!-- _______________________________________________________________________ -->
7213<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7214 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7215</div>
7216
7217<div class="doc_text">
7218
7219<h5>Syntax:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7220<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7221 any integer bit width.</p>
7222
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7223<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7224 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7225 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7226 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7227 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7228 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]7229</pre>
7230
7231<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7232<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7233
7234<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7235<p>The first argument is an integer value (result of some expression), the
7236 second is a pointer to a global string, the third is a pointer to a global
7237 string which is the source file name, and the last argument is the line
7238 number. It returns the value of the first argument.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7239
7240<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7241<p>This intrinsic allows annotations to be put on arbitrary expressions with
7242 arbitrary strings. This can be useful for special purpose optimizations that
7243 want to look for these annotations. These have no other defined use, they
7244 are ignored by code generation and optimization.</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7245
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7246</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7247
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7248<!-- _______________________________________________________________________ -->
7249<div class="doc_subsubsection">
7250 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7251</div>
7252
7253<div class="doc_text">
7254
7255<h5>Syntax:</h5>
7256<pre>
7257 declare void @llvm.trap()
7258</pre>
7259
7260<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7261<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7262
7263<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7264<p>None.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7265
7266<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7267<p>This intrinsics is lowered to the target dependent trap instruction. If the
7268 target does not have a trap instruction, this intrinsic will be lowered to
7269 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7270
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7271</div>
7272
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7273<!-- _______________________________________________________________________ -->
7274<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7275 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7276</div>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7277
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7278<div class="doc_text">
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7279
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7280<h5>Syntax:</h5>
7281<pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7282 declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7283</pre>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7284
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7285<h5>Overview:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7286<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
7287 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
7288 ensure that it is placed on the stack before local variables.</p>
7289
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7290<h5>Arguments:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7291<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
7292 arguments. The first argument is the value loaded from the stack
7293 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
7294 that has enough space to hold the value of the guard.</p>
7295
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7296<h5>Semantics:</h5>
Bill Wendlingf85859d2009-07-20 02:29:24 +0000[diff] [blame]7297<p>This intrinsic causes the prologue/epilogue inserter to force the position of
7298 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7299 stack. This is to ensure that if a local variable on the stack is
7300 overwritten, it will destroy the value of the guard. When the function exits,
7301 the guard on the stack is checked against the original guard. If they're
7302 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
7303 function.</p>
7304
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7305</div>
7306
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7307<!-- _______________________________________________________________________ -->
7308<div class="doc_subsubsection">
7309 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
7310</div>
7311
7312<div class="doc_text">
7313
7314<h5>Syntax:</h5>
7315<pre>
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7316 declare i32 @llvm.objectsize.i32( i8* &lt;object&gt;, i1 &lt;type&gt; )
7317 declare i64 @llvm.objectsize.i64( i8* &lt;object&gt;, i1 &lt;type&gt; )
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7318</pre>
7319
7320<h5>Overview:</h5>
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7321<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information
Eric Christopher184f44d2010-01-08 21:42:39 +0000[diff] [blame]7322 to the optimizers to discover at compile time either a) when an
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7323 operation like memcpy will either overflow a buffer that corresponds to
7324 an object, or b) to determine that a runtime check for overflow isn't
7325 necessary. An object in this context means an allocation of a
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7326 specific class, structure, array, or other object.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7327
7328<h5>Arguments:</h5>
7329<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher0101f9d2009-12-23 00:29:49 +0000[diff] [blame]7330 argument is a pointer to or into the <tt>object</tt>. The second argument
7331 is a boolean 0 or 1. This argument determines whether you want the
7332 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
7333 1, variables are not allowed.</p>
7334
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7335<h5>Semantics:</h5>
7336<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Eric Christophera1151bf2009-12-05 02:46:03 +0000[diff] [blame]7337 representing the size of the object concerned or <tt>i32/i64 -1 or 0</tt>
7338 (depending on the <tt>type</tt> argument if the size cannot be determined
7339 at compile time.</p>
Eric Christopher767a3722009-11-30 08:03:53 +0000[diff] [blame]7340
7341</div>
7342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7343<!-- *********************************************************************** -->
7344<hr>
7345<address>
7346 <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]7348 <a href="http://validator.w3.org/check/referer"><img
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Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7350
7351 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7352 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7353 Last modified: $Date$
7354</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7355
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7356</body>
7357</html>